The URL can be used to link to this page

Home My WebLink About; ; Environmental Impact Report, Improvement, Enlargement of the Buena Vista and Agua Hedionda Pumping Stations; 1974-10-11VISTA SANITATION DISTRICT CITY OF CARLSBAD A PROJECT AND ENVIRONMENT AL IMPACT REPORT FOR IMPROVEMENT AND ENLARGEMENT OF THE BUENA VISTA AND AGUA HEDIONDA PUMPING STATIONS OCTOBER 1974 00 BROWN AND CALDWELL CONSUL TING ENGINEERS PASADENA, CALIFORNIA GOVERNING OFFICIALS VISTA SANITATION DISTRICT BOARD Frank Meyer -Chairman Orbee V. Mihalek Gloria E. McClellan Lloyd D. Tracy Robert C. K. Foo CITY OF CARLSBAD CITY COUNCIL Robert C. Frazee -Mayor Glenn E. McComas -Vice Mayor Lewis L. Chase Claude A. Lewis Anthony J. Skotnicki PROJECT STAFF -BROWN AND CALDWELL ENGINEERING R. M. Hunter G. M. Jones T. V. Lutge J. C. Miller E. F. Mische, Ph. D. DRAFTING P. Gresko R. L. McCarthy E. Van den Boogart REPORT PRODUCTION B. E. Brannon M. Chapman E. Morzov Techni-Graphics, Inc. BROWN AND CALDWELL CONSULTING ENGINEERS October 11, 1974 Vista Sanitation District Post Office Box 188 200 West Broadway Vista, California 92083 Gentlemen: WALNUT CREE K PASADENA EUGENE D. H. CALDWELL, PE President J. T. NORGAARD, PE Vice President J.C. LUTHIN, PE Vice President L. B. DUNLAP, PE Vice President T. V. LUTGE, PE Vice President D. P. NORRIS, PE Vice President J. L. STURGEON Sec-Treas J. L. HARTFORD, PE G. M. JONES, PE T. R. LOVEJOY, PE M. L. WHITT, PE In accordance with the agreement for engineering services, dated June 25, 1973, we have completed the necessary studies and are submitting herewith a report which includes an engineering analysis and environmental impact assessment of improvements and enlargement of the Buena Vista and Agua Hedionda Pumping Stations. This report has been prepared in accordance with guidelines established by the State Water Resources Control Board and the Environment Protection Agency. The location of information and data pertinent to sections of the Environmental Im- pact Report is referenced in Appendix B. Following a review of environmental and wastewater characteristics, the existing pumping stations were evaluated with regard to both present operating efficiency and long-range capability. Based on projected development within the study' area, alternative improvement and expansion plans were developed on the basis of either (1) following the original design concept, or (2) making major modifications to the original design. Both alternative plans were formulated to provide for the projected needs of the area to the period 1995 -2000. The recommended project for the Buena Vista Pumping Station involves modification of the original design. By means of this project, the ultimate capacity of the facil- ity will be 19. 4 mgd, while the first phase expansion will provide a capacity of 13.0 mgd. The project proposed for initial construction is limited to the Phase I program and will serve the projected needs of the service area to about 1983. Phase I of the proposed modifications consists of series installation of the parallel 24-inch force main and pumping station additions. Addition of the parallel force main in Phase IA will increase the existing pumping capacity of 4.61 mgd to 6.34 mgd, while the provision of two pumps with a higher capacity than the existing pumps and pumping station modifications in Phase IB will increase the capacity to 13. 0 mgd. Adequate standby power will also be provided to convey the design flow. The cost of Phase I improvements at present price levels has been escalated to re- flect costs anticipated to prevail at the mid-point of construction. Accordingly, the project costs of the parallel 24-inch force main addition and pumping station improvements during Phase I are estimated to be $229,000 and $555,000, respec- tively. WATERWORKS ' DRAINAGE • WASTEWATER TREATMENT · RATE STUDIES · VALUATIONS · CHEMICAL AND BIOLOGICAL LABORATORIES BROWN AND CALDWELL 150 S ARROYO PARKWAY BIN 83 ARROYO ANNEX PASADENA, CA 91109 (213) 577-1020 Vista Sanitation District - 2 -October 11, 197 4 The recommended project for the Agua Hedionda Pumping Station also involves modification of the original design. By means of this project, the ultimate capacity of the facility will be 31. 0 mgd, while the first phase expansion will provide a capacity of 15. 0 mgd. The project proposed for initial construction is limited to the Phase I program and will serve the needs of the area to about 1980. During Phase I, a single pump with a capacity larger than the existing pumps, standby power and other pumping station improvements will be. provided. The cost projected to occur at the mid-point of construction in early 1977 is estimated to be $393,000. The financial responsibility for constructing the improvements to the pumping sta- tions was determined for the Phase I program. In accordance with prior agreements, Vista Sanitation District and Carlsbad will share the project costs of each pumping station improvement in direct proportion to the respective increase in capacity reservation at the completion of Phase I. The total cost to Vista Sanitation District and Carlsbad will be $651,000 and $133,000, respectively, for the Buena Vista facilities; while costs to the respective agencies for Agua Hedionda Pumping Sta- tion improvements would be $242,000 and $151,000. Furthermore, the capacity rights owned by each agency in the existing pumping stations were reallocated to correspond to the adjusted projected needs. The recommended Phase I construction program is expected to be completed by December, 1977, based on the following implementation and construction schedule. Submit and Review Design Report and EIR Prepare detailed plans and specifications: a • BV force main b. BV pumping station Construction a . BV force ma in b. BV pumping station Authorization received to prepare final plans for AH pumping station Prepare detailed plans and specifica- tions for AH pumping station Construction of AH pumping station August, 1974 to October, 1974 October, 1974 to February, 1975 October, 1974 to April, 1975 June, 1975 to December, 1975 September, 1975 to March, 1977 June, 1975 July, 1975 to January, 1976 July, 1976 to December, 19 77 - 3 -October 11, 1974 For the convenience of those interested persons who wish to acquire, as briefly as possible, a usable knowledge of the nature and scope of this study and our recommendations, we have included, as Chapter 2, a summary of this report. We will be pleased to discuss our findings and recommendations with you at your convenience. Respectfully submitted, BROWN AND CALDWELL ~~ Vice President E. F. Mische Project Engineer CONTENTS CHAPTER 1 • INTRODUCTION •.••••••••• Authorization and Scope of Project Study Planning Objectives and Goals •• Acknowledgements •••••••• CHAPTER 2. SUMMARY AND RECOMMENDATIONS Existing and Projected Planning Area Characteristics • • • • • • • • • Existing and Projected Water and Wastewater Characteristics ••••• Waste Discharge and Treatment Requirements •••••• Analysis of Existing Wastewater Facilities • • • • • ••••••• Project Alternative Analysis • • • • • • • • • • • • • • • Buena Vista Pumping Station -Plan BVl •••••••••••••••• Buena Vista Pumping Station -Plan BV2 • • • • • • Agua Hedionda Pumping Station -Plan AHl ••••••.•••• Agua Hedionda Pumping Station -Plan AH2 ••• Comparison and Evaluation of Alternative Plans ••••••••••• Buena Vista Pumping Station Alternatives • • • •• Agua Hedionda Pumping Station Alternatives • • • • Environmental Impact Statement • • • • • • • • • • • • • • • • • • • •••• Recommended Project • • • • • • • • • • • • • • • • • • • • • • • • • • • • Financial Plan . . . . . . . . . . . . . ................ . Recommendations •••• . . .. . . . . . . . . . . . . . CHAPTER 3. EXISTING AND PROJECTED PLANNING AREA CHARACTERISTICS • • • • • • • • • • • • • • Geographical Setting . . . . . . . . . . . . . . . . . . . . . . . Physical Geography and Topography . . . . . . . . Geology and Soils . . . . . . . . . . . . . . . . . Climate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Regional Air Quality . . . . . . . . . . . . . . . . . . . . . . Water Resources Environmental Setting •••••••••••• . . . Physical Features ••••••••••••••••••• Buena Vista Lagoon •• Agua Hedionda Lagoon ••••••••• Biological Systems and Inhabitants ••• . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Vegetation ••••••••••••• Animal Life • • • • • • • • • • • • . . . . . . . . . . . . . . . . . . . . . . . . . . . . Regional Plans for the Environment Local Noise Environment ••••••• . . . . . . . . . . . . . . . . . . . . . . Economic Activity ••••••••••• . . . . . . . . . . . . i . . . . . . . . . . 1 1 2 4 5 5 6 7 8 9 10 10 10 10 10 11 11 12 12 13 14 16 16 16 17 18 20 22 24 24 24 25 26 27 28 30 31 31 Land Use and Population Existing Land Use Future Land Use Population Growth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CHAPTER 4. EXISTING AND PROJECTED WATER AND WASTEWATER CHARACTERISTICS ••••• Water Supply . . . . . . . . . . . . Wastewater Characteristics •••••••••••••• Wastewater Composition ••• Wastewater Volume • • • • •••••••••• Dry Weather Flow • • • • • • Wet Weather Flow •• Design Quantities . . . . . . . . . . . . . . . . . . . . CHAPTER 5. ANALYSIS OF EXISTING WASTEWATER MANAGEMENT SYSTEM .••••.•••••••••. Institutional Arrangements •••••••••• . . . . Vista Sanitation District •••••••••• City of Carlsbad ••••••••••••••• Basic Joint Powers Agreement . . . . . . . . . . . . . . Wastewater Facilities .•••••• . . . . . . . . . . Interceptor Sewers • • • • • • • • • • • • •••••••• Vista Metering Station ••••••••••••••••••••••••• Pumping Stations •••••••••••••••••••••••••• Buena Vista Pumping Station ••••••••••••• Agua Hedionda Pumping Station •••••••••••••••••• Deficiencies in Present Operations •••••••••••• Encina Water Pollution Control Facility •••••••••••• Effluent Outfall • • • • • • • • • • • • • • • • • • • • • • • • • • • • • CHAPTER 6. WASTE DISCHARGE AND TREATMENT REQUIREMENTS. Water Quality Requirements and Goals •• Waters Affected by Wastewater Discharge Buena Vista Creek and Lagoon ••••• Agua Hedionda Lagoon • • • • • • • • • Need for Action • • • • • • • • • • • • • • • • • . . . . . . . . . . . . . . . . . . . . . . . CHAPTER 7. DESIGN CRITERIA AND BASIS OF COST ESTIMATES Preliminary Layouts Design Period ••••• Design Criteria ••• Force Mains •• . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pumping Stations Construction Costs ••• . . . . ii . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 32 33 34 36 36 37 37 39 40 41 43 46 46 46 46 47 48 48 49 49 49 50 51 53 55 56 56 57 58 58 58 60 60 60 60 61 61 61 Force Mains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pumping Stations Engineering Costs Annual Costs •••••• . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Interest and Depreciation Operation and Maintenance . . . . CHAPTER 8. PROJECT ALTERNATIVE ANALYSIS . . . . . . . . . . . . Initial Screening of Alternatives •••••••••••••••••••••••• Description of Alternatives •••••••••••••••••••••••••••• Buena Vista Pumping Station ••••••••••••••••••••• Plan BVl-Existing Design Expansion •••••••• Plan BV2-Modified Design Expansion •••••••••••••• Agua Hedionda Pumping Station ••••••••••••••••••• Plan AHl-Existing DesignExpansion •••••••••••••• Plan AH2-Modified Design Expansion •••••••••••••• Comparison and Evaluation of Alternative Plans ••••••••••••••• Economic Factors • • • • • • • • • • • • • • • • • • • • • ••••• Environmental and Socio-Economic Factors ••••••••••••• Environmental Impact ••••••••••••••••••••••• Regional Land Use •••••••••••••••••••••••••• Population Sensitivity •••••••••••••••••••••••• Flexibility and Reliability ••••••••••••••••••••• Implementation . . • .•....•....•....•...... Public Reaction . . . . . . . . . • . . • . . . . . . . . . . . • . Compatibility . . . • . . . • .•....••......•.... Selection of Recommended Plan ••••••••••••••••••••• CHAPTER 9. ENVIRONMENTAL IMPACT STATEMENT . . . . . . . . . . Probable Impacts on the Environment ••••••••••••••••• Long-term Impacts •••••••••••••••••••••••••• Short-term Impacts •••••••••••••••••••••••••• Probable Adverse Effects Upon the Environment Which Cannot be A voided . • . . . . • . . . . . . . . . • . • . . . . • . . • . • . . • . . Mitigation Measures Proposed to Minimize the Environmental Impact . . . . . . . . . • . . . . . . . • . • . • • . . . . . . . . . . . • . . Compatibility with Future Regional Management of Wastewater ••••••••••••• . . . . . . . . . . . . . . . . Water Quality Considerations ••• Air Quality Considerations ••••• Noise Considerations •••••••• . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . Construction Procedures •••••••••••••• Visual Aesthetics and Human Comfort •••••• Effects on Wildlife •••••••••••••••••• . . . . . . . . . . . . . . Earthquake and Flood Hazard Considerations iii . . . . . . . . . 63 63 65 65 65 66 68 68 69 69 69 71 72 72 74 75 75 76 78 78 78 79 79 79 79 80 81 81 81 82 83 83 84 84 84 85 85 86 86 87 Alternatives to the Proposed Action • • • • • •••••••••• Irreversible and Irretrievable Commitments of Resources •••• Possible Opposition to the Project • • • • • • • • Coordination of Public Views • • • • • • • • • • • • • • • • CHAPTER 10. RECOMMENDED PROJECT •• Buena Vista Pumping Station ••••••••• Description -Long-Range Plan •••• Initial Construction -Phase IA and IB . . . . . . . . . . . . . . . . Cost Estimate . . . . . . . . . . . . . • . . . . . . . . . . . . . . Agua Hedionda Pumping Station • • • • • • • • • • • • •••••• Description -Long-Range • • • • • • • • • • •••••• Initial Construction -Phase I • • • • • • • • • • • • • • • • • • Cost Estimate . . . . . • . . . . . . . . . . • . . • . . .. Implementation Schedule •••••••••••••••••••••••• Operating and Maintenance Program • • • • • • • • • •••• Basin Plan Analysis •••••••••••••••••••••••••••• Regional Land Use Plan Analysis • • • • • • • •••••••• Bypass Analysis . . . . . . . . . . . . .....•....•.... CHAPTER 11 . FINANCIAL PIAN . . . . . . . . . . . . . . . . . . . Methods of Financing ••••••••••••••••••••••• Sources of Revenue . • • • • • • • • • • • • • • • • • • • Ad Valorem Taxes ••••••••••••••••••• . . . . . . . Annexation and Connection Fees • • • • • • •• Sewerage Service Charges • • • • • • • • • • • • • • •• General Obligation Bonds • • • • • • • • • • •••••••••• Revenue for Administration, Operation and Maintenance •••• Assessment of Costs .............................. . Existing Agreements •••••• Determination of Cost Sharing APPENDIX A. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . APPENDIX B. Environmental Impact Report -Outline and Location· of Information iv . . . 87 88 88 88 89 89 89 90 90 90 90 92 93 95 97 98 98 98 99 99 99 100 100 100 100 101 101 101 102 CHAPTER 1 INTRODUCTION Vista Sanitation District proposes a project identified as the Enlargement and Modification of Buena Vista and Agua Hedionda Pumping Stations. The project involves design modifications to the existing pumping stations to in- crease capacity and improve reliability of the facilities. The proposed first phase of the project will provide additional capacity for peak wet weather · flows projected for about the year 1985, and will enhance the protection of the facilities from power failures and internal flooding. The pumping stations convey wastewater from Vista Sanitation District and the City of Carlsbad to the Encina Water Pollution Control Facility (WPCF) for treatment and disposal. The two agencies are part of the Encina Joint Sewerage Agency, a joint powers organization that owns and operates the Encina WPCF and Encina Ocean Out- fall and conveyance facilities on a regional basis. Authorization and Scope of Project Study By agreement dated June 2 5, 19 73, Vista Sanitation District, acting as administrator for Vista and the City of Carlsbad, engaged Brown and Caldwell, Consulting Engineers, to conduct the studies necessary to define the scope of the required project by investigating the existing pumping stations and evalu- ating the possibilities for expansion, and to proceed with a detailed pre- design report, an environmental impact report, and a financial program. This report, which is based on studies conducted under the agreement, describes existing and projected future conditions which necessitate facility modifica- tions; alternative plans and the recommended project; predicted environmental impacts of the recommended project; an implementation schedule for the pro- posed project; and the method of financing the project. The report presents information required by guidelines adopted by the State Water Resources Con- trol Board (SWRCB) as part of the Clean Water Grant Program. 1 The study area is located approximately 30 miles from San Diego and extends about 4 miles in a northwesterly direction along the coast and about 10 miles inland. Encompassing about 23,000 acres in north coastal San Diego County, the study area includes land in both the Buena Vista and Agua Hedi- onda drainage basins. The study area boundary has been established by deter- mining the area tributary to the respective pumping stations and is defined by both topographic and political boundaries. Although a part of the City of Oceanside covers a major portion of the lower half of the Buena Vista drainage basin, flows generated from this area will be handled separately by Ocean- side sewerage facilities. Conversely, however, the portion of the City of 2 Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations Oceanside which extends into the Agua Hedionda drainage basin will be con- sidered part of the study area. Small portions of the Vista Sanitation District to the north have been excluded from this investigation because they drain away from the Buena Vista basin and will be served by the City of Oceanside. The upper portion of the Agua Hedionda drainage basin is served by Buena Sanitation District. Because of topographic constraints, however, flow from Buena Sanitation District is pumped out of the basin and is therefore not tribu- tary to the downstream pumping facilities. In November, 1971 the Encina Regional Sewerage Survey I was completed and presented to the Encina Joint Advisory Committee. The Survey contains recommendations with regard to improvements and additions to the joint sewer- age system and has identified the need for enlargement of the pumping stations presented herein. A portion of this report includes some of the data developed in the Regional Sewerage Survey. Literature and other references cited by superscripts in the text of the report are listed numerically in Appendix A. Planning Objectives and Goals Wastewater must be conveyed, treated and disposed of in a manner which will protect the public health, maintain local water quality consistent with its beneficial uses, and prevent nuisance conditions. These objectives determine the planned capacity of the system and the degree and type of treatment which must be provided prior to disposal or reuse. . Improvements to the Buena Vista and Agua Hedionda pumping stations have been identified by the Comprehensive Planning Organization (CPO) in the document entitled "Water, Sewerage and Flood Control Systems Plan and Implementation Program." Construction of these improvements is recommended by CPO to be undertaken during the period of FY1974-75 to 1975-76. Specific requirements with respect to wastewater quality and to its effects on the quality of receiving waters, both surface and groundwater, are established for each discharge or water reuse by the California Regional Water Quality Con- trol Boards (RWQCB). The RWQCBs also require water quality monitoring pro- grams by dischargers, establish long-range objectives and policies, act upon applications for Federal and State grants and loans , and enforce requirements through orders and court actions. They operate under the general guidance and final authority of the State Water Resources Control Board (SWRCB). In addition to its regulatory powers, each RWQCB is charged with the responsibility of formulating and adopting long-range policy and objectives for water quality control within its region. The long-range policies of each RWQCB take the form of a Comprehensive Water Quality Control Plan. The Comprehen- sive Water Quality Control Plan for the San Diego Basin is completed and will be adopted shortly by the SWRCB. In order that waste treatment capacity can con- tinue to meet projected requirements, an Interim Basin Plan has been developed for each basin. The Interim Basin Plan for the San Diego Basin, which includes Introduction 3 the cities of Vista and Carlsbad, calls for the continued operation and enlargement of the regional wastewater transmission and treatment system which currently serves the northern San Diego County area2 . Implementation of the Buena Vista and Agua Hedionda pumping station improvements, as described in this report, will be a major step toward the planned protection and enhancement of the quality of the water resources in northern San Diego County. The following are the general objectives of the project. They include the project's socio-economic and environmental goals: Environmental Impact Protection of the Pacific Ocean. Protection of Buena Vista Lagoon. Protection of Agua Hedionda Lagoon. Protection of groundwater basins within the study area. A high "Expected Performance/Total Cost" ratio compared to other alternative plans. Regional Land Use Compatibility with existing plans for regional land use and development. Accommodation of planned population growth. Population Sensitivity Ability to adapt to population growth rate changes and to remain operable. Flexibility and Reliability Amenability to revision to accommodate changing patterns of urban development with no compromise of performance. A high degree of assurance of expected project performance. Minimum consequences from system failures due to a natural disaster or catastrophe. Minimum mechanical and process failures, minimum consequences from such occurrences • Implementation Capability of rapid implementation. Minimum legislative,financial, and logistical obstacles. Local governmental acceptance • Public Reaction Attractiveness to the public. Acceptance of the design and reports by local public groups. 4 Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations Compatibility Accomplishment of objectives of interim water quality control plan. Consistency with established regulatory agency policies. Acknowledgements For their assistance and cooperation during the course of this study, we wish to express our appreciation particularly to Mr. Charles B. Old sen, Princi- pal Sanitary Engineer, San Diego County Department of Sanitation and Flood Control; Mr. Wayne Elliott, Sanitary Engineer, Vista Sanitation District; Mr. Ronald Beckman, Director of Public Works, and Mr. Timothy C. Flanagan, City Engineer, both of the City of Carlsbad. CHAPTER 2 SUMMARY AND RECOMMENDATIONS The preparation of this report was authorized by the Board of Directors of Vista Sanitation District in July 19 73 on behalf of the District and the City 5 of Carlsbad as one of several steps necessary to develop and define a sewerage project which will meet all applicable requisites for (1) regional wastewater management, (2) local planning objectives, and (3) State and Federal require- ments for water quality control. Present wastewater loadings are approaching the nominal capacity of the jointly owned Buena Vista and Agua Hedionda pumping stations. A project for new facilities to improve operation of the stations, increase reliability, assure protection of public health, and permit normal urban growth of the area is urgently needed. A report prepared for the Encina Joint Sewerage Agency, the Encina Regional Sewerage Survey, submitted November 18, 19 71, originally identified the need for the project and serves as a basis of this report. An Environmental Impact Report on the proposed project is contained in Chapter 9 of this report, thereby serving as an integral part in the selection of the recommended project. Sup- portive information to the impact assessment is referenced in Appendix B. This summary is intended to present in brief form the more significant background information, findings, conclusions and the recommendations of the report. The reader is referred to the full report for continuity, supporting and auxiliary data and conclusions of lesser impact. This summary is organized by chapters. EXISTING AND PROJECTED PIANNING AREA CHARACTERISTICS Environmental characteristics within the defined planning area include physical aspects, socio-economic conditions and land use. These character- istics affect both present and projected population and its distribution. The study area under consideration includes primarily the portions of the Buena Vista and Agua Hedionda drainage basins which fall within the political boundaries of Vista Sanitation District and the City of Carlsbad. A portion of the City of Oceanside within the Agua Hedionda basin will also be considered in the study. The study area is located approximately 30 miles north of San Diego and extends about 4 miles in a northwesterly direction along the coast and about 6 Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations 10 miles inland, encompassing about 23,000 acres. Similar to the topography of most of San Diego County, the study area may be divided from west to east into two major sections: (1) a coastal plain section characterized by prominent marine wave cut terraces, locally interrupted by stream channels conveying water from the eastern highlands to the Pacific Ocean, and (2) a mountain- valley section. Typical of most of coastal southern California, the weather of San Diego County is profoundly influenced by the Pacific Ocean and its semi-permanent pressure systems that result in a dry, warm summer and a wet, cool winter. The moderating influence of the ocean is felt along the coastal plain and in the coastal valleys, and the temperature range increases with distance inland. Although air quality is generally good, the area is subject to drift of pollutants from the Los Angeles and San Diego metropolitan areas as well as those pro- duced locally. Implementation of the State of California's emission control strategy has resulted in a decrease in the emission of critical air contaminants and an improvement in air quality compared to 19 70 levels. Agriculture has historically been an important industry in and adjacent to the study area with flowers, eggs and tomatoes as the prime crops. Outside the metropolitan core of San Diego,industrial developments have been slow to ex- pand. In recent years, assembly plants and light manufacturing industries have started to locate in outlying parts of the County. Due to the relatively small amount of industry, much of the local working force is employed outside of the study area, commuting to either Escondido, Oceanside, Camp Pendleton or San Diego. Due to the presence of the Pacific Ocean and several quiet embay- ments and estuaries, many water-oriented recreational activities are conducted in and near the study area. Land use planning in the study area has been undertaken by the cities, as well as the County. A principal feature of the land use plans is the gradual change in land use from rural or agriculture to residential, commercial and industrial activities. Land adjacent to major transportation links in the study area has been reserved for industrial development. Present population (19 73) in the planning area is approximately 43,000, of which about 25,000 people live within the City of Vista and 18,000 within the City of Carlsbad. Utilizing population projected from data supplied by the local planning agencies, population in the study area is expected to increase to 88,000 by 1985 and 144,000 by the end of the century. Alternative sewerage plans presented herein will be based upon the projected population at the year 2000 of about 99,000 and 144,000 for Buena Vista and Agua Hedionda pumping stations, respectively. EXISTING AND PROJECTED WATER AND WASTEWATER CHARACTERISTICS The water supply for the study area is principally Colorado River water obtained from the Metropolitan Water District through the San Diego County I ' Summary and Recommendations Water Authority. Vista Irrigation District obtains a supplemental supply of water from Lake Henshaw in quantities dependent on rainfall and runoff during the winter months. Colorado River water contains moderately high concentra- tions of total dissolved solids, hardness, sodium and sulphate concentrations which reduce the usefulness of this water for domestic and industrial uses. Average dry weather flow (ADWF) in the study area generally averages about 90 gallons per capita per day (gpcd) including both domestic, and com- mercial and industrial flows. The wastewater is discharged primarily from domestic sources, with all industries contributing only about 1. 4 percent of the wastewater flow. The peak dry weather flows from Vista generally fol- low the same peak to average ratios observed for many California communities with a given contributory population. Sewerage systems in the service area admit surface and groundwater dur- ing wet weather. The capacity of both the Buena Vista and Agua Hedionda pumping stations, however, has been adequate to prevent the bypassing of raw wastewater to either Buena Vista or Agua Hedionda lagoons. During the winter of 19 6 8-19 69 , one of the wettest during recent years, peak wet weather flow (PWWF) rates of greater than three times average dry weather flow (ADWF) were recorded at the Vista metering station. During this period, inflow and infiltra- tion rates of 690 and 190 gallons per acre per day (gad) were calculated for the tributary area • 7 Unit design loadings for the project were developed on the basis of exist- ing characteristics and are as follows: Average dry weather flow Domestic, gpcd Commercial and industrial, gad Peak dry weather to average dry weather flow ratio- dependent on contributory population; e.g. 10,000 people 50,000 people 100,000 people Wet weather flow, gad Infiltration Direct storm inflow WASTE DISCHARGE AND TREATMENT REQUIREMENTS 90 2500 1.81 1.55 1.51 250 750 Wastewater management policies and requirements are established by governmental regulatory agencies. Control of wastewater disposal in San Diego County is vested in the San Diego Regional Water Quality Control Board (SD RWQCB). The SDRWQCB operates under the general guidance and final authority of the State Water Resources Control Board. Discharge requirements are established under a cooperative agreement with the U.S. Environmental Protection Agency under the National Pollutant Discharge Elimination System (NPDES). 8 Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations Discharge requirements for the Encina Water Pollution Control Facility . (WPCF) were outlined in Order No. 74-21 (NPDES No. CA 0107395) which was adopted by the SDRWQCB on May 20, 1974. Both the SDRWQCB and the EPA prohibit wastewater treatment plant and upstream sewer bypasses. In the dis- charge requirements established by the SDRWQCB for the Encina WPCF is the following provision: "Bypassing or direct discharge of treated or untreated liquid or solid wastes to any inland watercourse is prohibited." ANALYSIS OF EXISTING WASTEWATER FACILITIES Vista Sanitation District and the City of Carlsbad initiated regionaliza- tion of sewerage service in 19 61 by formulating the basic Joint Powers Agree- ment. Subsequent to that agreement, Buena Sanitation District, San Marcos County Water District, Leucadia County Water District and Encinitas Sanitary District have become joint owners in the Encina Joint Sewerage Agency. Repre- sentatives of these agencies form the Joint Advisory Committee {JAG) for the purpose of advising on the operation and administration of jointly owned waste- water transmission, treatment and disposal facilities. The existing regional sewerage system consists of pumping stations and interceptors, Encina WPCF and the ocean outfall. Conveyance facilities of the joint sewerage system serving Vista and Carlsbad include the Vista outfall, the Carlsbad interceptor, the Agua Hedionda outfall and the Buena Vista and Agua Hedionda pumping stations • The Buena Vista Pumping Station contains three pumps with a rated capacity of 3200 gpm (4. 61 mgd) with one pump serving as standby and a standby power source which would allow a pumping capacity of 2500 gpm (3. 6 mgd). Space has been provided in the station for two additional pumps. A deficiency in the con- figuration of the wet well would allow the entire station to be flooded from the inside. Although the 16-inch force main is only adequate for flows 3 to 4 years in the future, a partially completed 16-inch parallel force main has been con- structed. The Agua Hedionda Pumping Station contains three pumps with a total pumping capacity of 7200 gpm (10. 4 mgd) with any two pumps operating. A stand- by power source capable of providing a pumping capacity of 3100 gpm (4. 5 mgd) is available. Space has been provided in the dry well for one additional pump. The location of the motor control panel in the dry well, however, creates a problem of potential flooding. The 18-inch force main is adequate for projected wastewater flows but excessively high velocities in the force main at maximum flow rates dictate that relief should be provided in the future. Summary and Recommendations 9 The Encina WPCF provides primary treatment and presently has an average dry weather flow (ADWF) capacity of 6. 75 million gallons per day (mgd}. During the Phase II and IIA enlargement currently under construction, the ADWF capacity is being increased to 13. 7 5 mgd by adding a fourth and fifth primary sedimenta- tion tanks. Wastewater conveyed to the plant enters by gravity and passes through a bar screen, an aerated grit removal unit and primary sedimentation tanks. Effluent may be chlorinated prior to discharge to the ocean outfall. Putrescible solid residues from the primary sedimentation process are stabilized by anaerobic digestion. The digested sludge is dewatered by centri- fugation and the centrate is transferred to drying beds. After dewatering, the sludge and dried centrate is pulverized for use as a soil conditioner. The original effluent outfall is a 48-inch diameter reinforced concrete pipe which crosses approximately 1,100 feet of land prior to extending 5,500 feet in the ocean and terminating at a water depth of 100 feet below mean sea level. During the Phase II construction program, the ocean outfall was extended approxi- mately 2,300 feet to a maximum depth of approximately 1 70 feet. PROJECT ALTERNATIVE ANALYSIS Development of alternate plans for the pumping stations is generally limited to consideration of the location of the station, the ultimate capacity, phasing of capacity, and the necessity of the project. The alternative of no project could be justified only by providing upstream treatment and reclamation or by allowing no further growth in the area. Provision of upstream treatment facilities would be in direct contrast to the joint regional system concept which has been followed in the past and which is advocated by governmental agencies. Furthermore, con- struction of additional treatment facilities would be expensive and would have to meet stringent quality requirements for inland disposal. Alternatives for each of the two pumping stations were developed and in- vestigated with regard to ultimate and incremental capacity. Alternative projects presented herein provide increased capacity by (1) expanding the existing stations in accordance with the original designs, and adding an additional pumping sta- tion, and (2) expanding the pumping stations through major modifications of the original design. Alternative projects formulated herein have been sized to provide capacity for wastewater flows projected to occur about the year 2000. Economic analyses have been based on phased enlargement of the facilities. For plans in which expansion follows the original design, there is insufficient capacity for projected flows. In order to compare alternatives on an equitable basis, there- fore, a parallel pumping facility has been provided to increase the capacity of the systems to a level similar to the alternatives which modify the original de- sign. 10 u Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations Buena Vista Pumping Station -Plan BVl This alternative would provide an increase in pumping capacity of the existing station to 5200 gpm (7 .48 mgd) and would provide a standby power source of 400 10N. Furthermore, improvements would include isolation of the wet well and installation of a parallel 16-inch force main. The project cost of work on the existing station would be $400,100. In order to provide capacity to meet the year 2 000 demands, however, an additional 12. 0 mgd pumping station and 21-inch diameter force main would have to be provided. Provision of the additional pumping station would increase the overall project cost by $1 / 61 7 / 700 • Buena Vista Pumping Station -Plan BVZ Alternative BV2 would provide an increase in pumping capacity to 13,500 gpm (19. 5 mgd) which would be insured by a standby power supply of 900 10N by means of modifications to the original pumping station design. The wet well would be isolated from the station and modified to eliminate suction inlet vor- texing, while a new, high capacity ventilation system will be installed. To achieve the desired capacity, the partial 16-inch force main would be completed with a 24-inch pipe. The total project cost of improvements contained in BV2 would be $1,151,200. Agua Hedionda Pumping Station -Plan AHl Alternative AHl would provide an increase in pumping capacity to 11,000 gpm (15. 4 mgd) in accordance with the original design and would include a similar standby power pumping capacity by means of a supplemental power source of 225 10N. The project cost of this expansion would be $172,200. To provide capacity to meet the year 2000 demands, however, a parallel 16 mgd capacity pumping station and 24-inch force main would be constructed with an additional project cost of $1,246,000. Agua Hedionda Pumping Station -Plan AH2 Alternative AH2 would provide an increase in pumping capacity to 21,700 gpm (31. 0 mgd} which would be insured by a standby power supply of 900 10N. A parallel 18-inch diameter force main would be installed to reduce velocities in the existing force main at maximum flow. Modifications would also include relocation of the motor control center from the first level to the second level , isolation of the wet well, modification of the wet well to eliminate suction in- let vortexing and installation of a new, high capacity ventilation system. The total project cost of AH2 is $757,200. Comparison and Evaluation of Alternative Plans All four alternatives have been evaluated on the basis of meeting existing water quality criteria and the total cost effectiveness of each individual project. Summary and Recommendations The results of these evaluations are discussed below and summarized in Table 2-1. Table 2-1. Summary Comparison of Alternative Plans Buena Vista Pumping Station Agua Hedionda Pumping Station Factors Plan BV 1 Plan BV 2 Plan AH 1 Plan AH 2 Total capital cost, dollarsa 1,617,700 1,151,200 1,246,000 757,200 Total annual cost, dollarsb 169,600 129,100 130,300 86,000 Environmental impact Marginal Good Marginal Excellent Regional land use Adequate Good Adequate Good Population sensitivity Good Excellent Good Excellent Flexibility and reliability Good Excellent Good Excellent Implementation Adequate Good Adequate Good Public reaction Marginal Good Adequate Good Compatibility Excellent Excellent Excellent Excellent Overall ratingc Adequate Good Adequate Excellent a Based on ENR Construction Cost Index of 2200. Includes allowance for contingencies, engineering and project administration. b 30-year amortization at 7 percent interest. c Based on the average of ratings given to all factors with numerical equivalencies: Poor= 0, Marginal= 1, Adequate = 2, Good= 3, Excellent= 4. 11 Buena Vista Pumping Station Alternatives. Plan BV2 is less expensive and involves relatively minor construction, and it does not require the erection of an additional pumping station. Future flow projections indicate that both Plans BVl and BV2 would be adequate until the year 2000, and would maintain local water quality standards. The possibility of future damage from external flooding is minimized by flood dikes surrounding the existing station. By means of adding a second pumping station, Plan BVl creates major construction activity adjacent to Buena Vista Lagoon. Plan BV2 would require less operator attention and would be more likely to remain trouble free than the proposed two adjacent facilities. The compact nature of Plan BV2, in addition to its lower total costs, favors modi- fying the original design to achieve the required capacity. Agua Hedionda Pumping Station Alternatives. Plan AH2 is considerably less expensive and involves only a small amount of additional construction. By simply modif¥ing the existing station, .however, this alternative plan pro- vides adequate pumping capacity in the future to insure protection of local water quality. Implementation of Plan AH2 will provide sufficient pumping capacity in the existing station to meet the projected year 2000 flow rates, while future flow projections indicate that construction of the additional pumping station in Plan AHl will be necessary by 1980. Similar to Plan BVl, AHl would create major construction activity adjacent to a coastal lagoon. The station redesign as set forth in Plan AH2 will provide a more complete and workable configuration for future operation and maintenance. 12 Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations ENVIRONMENTAL IMPACT STATEMENT The pumping station modifications and enlargements will result in several impacts on the City of Carlsbad environment. Long-term impacts include contin- ued compliance with State standards for receiving water quality, increased elec- trical power requirements, creation of additional noise, odor and air pollutant sources and secondary impacts due to the population growth that the projects will support. Short-term impacts during construction include adverse effects on aes- thetics and human comfort, noise which may disturb bird populations and traffic congestion. In general, however, no significant permanent effects will be in evidence subsequent to construction. Several mitigation measures are proposed to minimize the environmental impact of the project. The project is compatible with the State Interim Water Quality Control Plan for the San Diego Basin and with the CPO Water, Sewerage and Flood Control Systems Plan and Implementation Program. It will allow com- pliance with water quality objectives and discharge requirements for the San Diego Basin, and, according to the State Air Implementation Plan, from an air basin- wide view point, the planned growth of the area will not result in a degradation of air quality below national ambient air quality standards. Construction proce- dures will be established that will insure that significant adverse short-term effects on visual aesthetics and human comfort and wildlife will not occur. Ir- retrievable adverse impacts associated with expansio e m in stations would be insignificant in view of resent se. A hearing will be held to m o m e pu ic of the nature of the potential impacts of the proposed project on the environment. RECOMMENDED PROJECT Both Buena Vista and Agua Hedionda Pumping Stations should be modified so that they may eventually be expanded to meet the projected year 2000 waste- water flows, and protect local water quality. This goal should be accomplished in the least expensive, most cost-effective manner. The results of comparison of the costs and socio-economic factors for each alternative indicate that Plans BV2 and AH2 are the optimum plans for each pumping station. The improvement for each pumping station may be divided into several phases, the first of which should be undertaken immediately. The Phase I project for Buena Vista Pumping Station is divided into two portions, identified as IA and IB, to expedite an increase in pumping capacity The Phase IA of the proposed modifications to the Buena Vista Pumping Station consists of concurrent installation of the parallel 24-inch force main and pumping station additions, Addition of the parallel force main will increase the existing pumping capacity to 4400 gpm (6 .34 mgd) with two pumps on and 6100 gpm (8. 78 mgd) capacity with all three pumps in operation. J,., Phase IB of the Buena Vista Pumping Station improvement program provides for the installation of two new 10 x 10 x 21 pumps to supplement the existing -- Summary and Recommendations 13 pumps and extensive modifications to the existing wet well, including modifica-. ,. tions to the suction nozzles of the new pumps. The capacity at this point will be 9000 gpm (13 mgd) with one new pump and all three existing pumps in oper- ation, while a capacity of 9600 gpm (13. 8 mgd) could be realized with all five pumps operating. This capacity corresponds closely with the existing capacity of the receiving interceptor sewer system in the City of Carlsbad. A single 350 J0N turbine generator will also be installed as a standby power source. The total project cost for the additional Buena Vista Pumping Station capacity provided by all construction phases is estimated to be $1,151,200, of which $669,400 is required for Phase I modifications, at present price levels. The actual cost of Phase I improvements must be escalated, however, to reflect the ENR index prevailing at the mid-point of construction. The project costs of the parallel 24-inch force main and Phase IB pumping station improvements are esti- mated to be $229,000 and $555,000, respectively, at ENR indices of 2420 and 2660. The estimate is based on a 10 percent annual escalation and includes an allowance for contingencies, contractor's overhead and profit, and engineering. During Phase I modification of the Agua Hedionda Pumping Station, a single 12 x 12 x 21 pump will be installed with its motor exposed at ground level. The standby engine will be removed and replaced with a 225 r:N' turbine generator, located outside the station, while new pump, motor and standby controls will be located inside the existing structure at the upper level. The capacity after completion of Phase I will be 10,400 gpm (15. 0 mgd) with all three of the existing pumps in operation and the new pump serving as standby. The total project cost for the additional Agua Hedionda pumping station cap- acity provided by all construction phases is estimated to be $752,200, of which $295,000 is required for Phase I modifications at present price levels. The actual cost of Phase I improvements must be escalated, however, to reflect the ENR index prevailing at the mid-point of construction. The project cost of Phase I is estimated to be $393,000 at an ENR index of 2930 occurring in 1977. FINANCIAL PIAN Although originally included in the 1973-74 fiscal year statewide list, chances of Federal and State rant funding for the um i statio eliminate w en t e SWRCB adopted a priority list for grant eligibility subsequent "'to initiation of engineering studies. The cost of the pumping station improve- ments must, therefore, be borne by the local participating agencies. One of the problems common to public works projects of the magnitude considered herein is that of developing an adequate and economical procedure to finance construction and provide funds for operation and maintenance. In this section of the report, the projected financial requirements of both Vista Sanitation District and the City of Carlsbad to construct the proposed project are presented and possible sources of revenue are discussed. Two basic methods available to a governmental body for funding the con- struction of sewerage projects are: (1) payment from current revenue or reserves C 14 Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations created from such revenues, and (2) payment with borrowed funds. In the first instance, current revenues and contributions are accumulated until construction can be financed on a pay-as-you-go basis. The financial resources of a City or Sanitation District stem from its ability to levy taxes and to obtain revenue from other sources such as annexation fees, connection fees and service charges. Generally an agency will obtain revenue from a combination of these sources. Borrowed funds, on the other hand, are obtained from the sale of either general obligation bonds, for which the full faith and credit of the issuing agency are pledged, or limited obligation bonds, which comprise special assessment and revenue bonds. Determination of the financial responsibility for constructing the improve- ments to the pumping stations is limited to the Phase I program. The cost sharing basis for engineering services as set forth on June 7, 1973 in a supplement to the Basic Agreement of the Encina Joint Powers is followed in allocating total project costs to each agency. Vista Sanitation District and Gar] sbad will share the costs in direct proportion ra 1be i;grpectjve increase io PW¥ff capacity reservation in each of the joint facilities at the end of the Phase I enlargement. The total cost of Phase Lconstruction to Vista Sanitation District and City of Carlsbad will be $651 , 000 and $133,000, respectively, for the Buena Vista facilities while costs to the respective agencies for Agua Hedionda Pumping Station improvements would be $242,000 and $2:,_51, OOQ.~ Furthermore, the original investment in the existing permanent structural facilities must be re-allocated to reflect revised distribution of capacity. Carls--bad re uires an add· · al capacity in the Bu v· umping Station. while Vista Sanitation District requires a 2. 0 percent increase in the capacity rights at the Agua Hedionda pumping station subsequent to Phase I enlargement. The difference between the present value of the actual investment by each agency and the present value of the required ownership rights must be transferred from one agency to the other in exchange for additional capacity rights. On this basis, therefore, Carlsbad roust ;pay; $35,000 to Vista Saoit.tigR. Dietrk.t for Buena Vista facilities, while Vista Sanitation District must pay $3,000 to Carlsbad for ownership rights in the Agua Hedionda facilities. RECOMMENDATIONS Based upon the findings of this report and considering the need for timely action on implementing the modification and enlargement of the Buena Vista and Agua Hedionda pumping stations, it is recommended that: 1. The recommended long-range plans for pumping station improvements, designated in this project report as Plans BV2 and AH2 be adopted by Vista Sanitation District and the City of Carlsbad to meet the projected needs of the study area. Summary And Recommendations 15 2. Steps be taken to provide local funds for the construction of Phase IA and IB modifications and enlargement of the Buena Vista Pumping Station. 3. Improvement costs be allocated on the projected capacity requirements of each agency at the end of Phase I and ownership rights be equitably adjusted to reflect any changes in capacity. 4. Implementation of the recommended plans proceed based on the follow- ing schedule: Submit and Review Design Report and EIR Prepare detailed plans and speci- fications: a • BV force ma in b. BV pumping station EIR review and approval Permit from San Diego Coast Regional Commission Advertise for bids and selection of contractors a. BV force main b. BV pumping station Construction a. BV force main b. BV pumping station Authorization received to prepare final plans for AH pumping station Prepare detailed plans and specifications for AH pumping station Advertise for bids and selection of contractors for AH pumping station Construction of AH pumping station August, 1974 to October, 1974 October, 19 7 4 to February, 19 7 5 October, 1974 to April, 1975 October, 19 7 4 to November, 19 7 4 November, 19 7 4 to December, 1 9 7 4 March, 1975 :May, 1975 June, 19 75 to December, 19 75 September, 19 7 5 to March, 19 77 June, 1975 July, 1975 to January, 1976 February, 19 7 5 to March, 19 76 July, 19 76 to December, 19 77 16 CHAPTER 3 EXISTING AND PROJECTED PLANNING AREA CHARACTERISTICS Planning and development of wastewater management systems requires an adequate knowledge of the existing and projected characteristics of the area to be served and protected. In this chapter, a description of study area charac- teristics is set forth in terms of geographical setting, the environmental setting and urban development. GEOGRAPHICAL SETTING The physical characteristics of the study area exert a major influence on the location and design of facilities to convey, treat and dispose of wastewater. Characteristics of the geographical setting important to a study of this nature include physical geography and topography, geology and soils, climate, regional air quality and hydrologic features. Physical Geography and Topography Physical geography is concerned with the physical features of the earth and their influences on design, construction, cost, and operation of wastewater transmission facilities. Watershed areas are of particular significance in defin- ing tributary areas and developing the corresponding dry and wet weather flows. Topography, as related to ground slope and natural drainage features, will deter- mine the size and location of future sewer additions, while the area tributary to a common collection point will determine the necessity for, and location of, wastewater pumping stations. Furthermore, topography has a direct relation on the growth and distribution of future population. As shown in Figure 3-1, the principal physical features of the study area include Buena Vista and Agua Hedionda Lagoons, Buena Vista and Agua Hedionda Creeks, Marron Canyon and the San Marcos Mountains. Topography of land in and adjacent to the study area is similar to most of San Diego County, and can be divided from west to east into two major sections. The coastal plain region is characterized by prominent marine wave-cut terraces which are interrupted by the two creek channels conveying water from the eastern hills to the Pacific Ocean. The coastal plain consists of a strip about 8 to 10 miles wide with topography which appears as flat-topped mesas or terraces, averaging about 500 feet in elevation. The inland region is primarily rolling ' .. t ... I ,,., / "·• " ~,· ,. w .;-" :i. ;#. " ~.. ~~ .. ' J' ~\ ~~ ~';::'»\ ,.,"~ 1 < I I, I .~ ! L /:. no'., -:-,. A .. • .;/'·" --~:::. --.---.... -:-~ .,," .. ,_____ ~~--~ ..... -:.:z-i,1 I \ ~t(~~-~i~4~-:; .. ~' ~ i.?,.:,, "·•, ' " I• ,,.,✓· t. \ -J'~ . ''(e_' \ ·\. -.,,. ,t;'t:~ ~-:~ .~·~ t ~-.... t; -~ --~.) ,, "--·,y,' I t. ,, : ,.',t ., '>, . .,. , , ~ .. • • t_ .~ .. .s:·1 l, \:, .,' II,-,, ,-'·' . • £ ' ,,,-,\;_ ,., __ . <o' ' , ''fy: I .,,:e:, \ ~~cL~, . r'O!:?J./!I; ,, .... _ ..,';J .. _·:~• r. -~-'"--··'],, ..... 'J/l /.~~ .... .. \t~·e'"" .4' ' , -~m ,-,;, ' . t,,, -C ~,._ ;./ .'flt' I • ·":'-1 • •.., " -\ ,/, / -f'.. ! , .., "' --~ ,,, .• , "\ l:;,'j, \_ . • .,,. ( . -/,•--•~ •" ' . I ! .:~-\ • • • "t '• . •. :0:' -•·~ I ) • ' ·'' , ,...,.,. ' "'l .. ~~' ; .. ,. 1;• 1 :, -, \ ';' •t,,"> _____ ,,;.;k: __ .. ., ..... .• -r-':" /~-+.r-i?•'. I "' C• p "' .. _ 0 "-~ 7 2000 •• .:111. -..,. ,,• ).(' .,. •' ,, ?:\ '.... . ~ .;;_--, ~.,.. ......_,. . .,,. ..,..,,. .. ;f _...,-.... -' ~ ..... . . .~••if ~ + • ~ \ ::~!-'f'.':? . \ ,-~\ •'. Bu EN A •P .. ' ..\ .,. .,. ~' ~--~-,. .. ~ ;K t :',' ·/, f~:-, •' ,/_. ·-'i~~:. l.''-'-i"· '{.,,., . ,,. 1/, ~ \ " .. ... . . . ~17.'c.-.. 4--~ 1~ ~ '":~:.~-;;::: ... , t .. <"f ~:.· .. ~' f1 .J' ...-(,\;:;. .. ' \ .f.. G~-~~, A ' HElulONDA •-...1 fl ' f) A .. ... -:,_ -v•-" SCALE IN FEET 2000 4000 .('f~ ------....,,,, -,--:~ '"•-..,,, .. • ·I ~€!TY OF_ . 1t,l· ' ... D -~-;,.. ~~ /.•~· CARLSM, ~""-~•~/'.. ; \ ~,\. ~---'-" ,_ ' ' \ -s--..... ,..,., ,. ' .,;y. '""i, ·~ ' -'IA"/ ~ ' ·-;,~ ':> --.. ' -.• ~ . .....· /# ti:_..----~ -' " rl. l A t1 /E lJ \i ~ •,1 -------· ,...-·•· ' . . ,, ·" ~" ... ' --· ,( ENCINAS <-.----+ 1A ~00 .., ':" ~. ' . '\ .,,,_ I,. ·, ) I r, 'l-b \' ~,: "-~.', ' ........ ~,~:~~ ,,, ... fif~ :'-, ... I •~1 "} ,',,t·~ ~ i J!l\ ... ~ \_ ~ .. ~~) ..... ---\ \ \ ,. I '!i.. ., i~ ....... ,, ..,,_. /, , ...... ·,,;r,-, l , .. ,,_ ' "''f ... , ... ..... ~ ... <~~ ,.,. '""" •·1~' ~ . 4 \ '4.. r ,.. VISTA SANITATION DISTRICT .,,._.r '( 'I '-l :-:.~~ .. ~, .... -.I ~· ~--,., '\;, '!.}_,~,-•. . \. , /;" --ll1. I I \ \ , ( I I I J .;";>,•, ' ' J I I , '1.(:1'' 1J ... ... ··-.t·, .. -:., ,.,, BUENA SANJTA TION DISTRICT "t .af.l ,.,~ ► •J-,: .. -~!r -.• . --i-LEGEND STUDY AREA BOUNDARY ... 1 ~ f ,. '·. ,, I i'" ... l I 'i-,. r...., _1 , .. , ~ .... ~ .. ~ .. --:· f,-: J· "\ .• \"j~;··•-,i,\:: SERVICE AGENCY BOUNDARY DRAINAGE BASIN BOUNDARY <!', .L '· ·--~', .. ,_, ' "r Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations foothills and mountain-valley terrain. In this area, elevations range from 500 17 to 1500 feet, with the highest points located on the western side of the San Marcos mountains, northeast of the City of Vista. These mountains form the eastern boundary of the drainage basin which is tributary to Buena Vista Creek. The re- mainder of the study area includes the western half of the basin drained by Agua Hedionda Creek. The upstream portion of Agua Hedionda drainage ba.sin is gravity connected to the downstream portion only by a narrow constriction in the creek. Sewerage service in the upstream portion of the basin is presently provided by the Buena Sanitation District which pumps wastewater to a regional gravity sewer located in the adjacent Encinas basin. Geology and Soils Geologic formations and groundwater levels encountered in the construc- tion of pipelines and other structures affect design and construction requirements and have a direct bearing on the cost of such facilities. Geologic conditions and soil characteristics influence infiltration into sewer lines as well as ground water percolation. Geological uplift along the shoreline has resulted in the formation of steep bluffs up to a hundred feet in height. The bluffs in the study area are interrupted by the two coastal lagoons, which have been formed through erosion by waters of the tributary creeks. Moving eastward from the coast, a coastal plain about 10 miles in width slowly rises to an elevation of about 500 feet at the easterly edge of the plain. The coastal plain consists of Pleistocene and Eocene (La Jolla Formation) sedimentary deposits of marine origin, which have been exposed through land uplift .1 These deposits are covered in places by a thin layer of quaternary deposits. Soils are derived from shale, sandstone, limestone and other similar semi-consolidated materials. The valleys incised in these sedi- mentary deposits have been subsequently backfilled with Recent Alluvium. Soils in the coastal plain area show wide variations in character and demonstrate no well-developed geological pattern. Alluvium and the La Jolla Formation are the major water-bearing sediments in the coastal plain section, in which alluvium probably attains a maximum thickness of 100 feet. The beach cliffs and terraces are the result of wave erosion and deposition by shore currents, together with changes in the elevation of the land with respect to sea level. Some of these coastal features show that definite changes in ele- vation have taken place in the history of this area. The present estuaries and coastal lagoons were formed when the coastal lands sank and the water-carved valleys were filled by sediments transported down by streams, while waves and shore currents built up beach ridges across the mouth of the lagoons. These ridges, in most cases, completely cut off the lagoons from the ocean except in times of flood and have thus caused a damming effect, which accelerates the deposition of sediments transported by the upstream waters. Buena Vista Lagoon is presently cut off from the ocean, while the mouth 18 Existing and Projected Planning Area Characteristics of Agua Hedionda Lagoon is kept clear of sediment buildup, thereby permitting tidal exchange. The mountain-valley area is characterized by mountains and intermontane basins and constitutes approximately one-fifth of the study area. Alternating broad, narrow valleys generally paralleling the coast are cut by canyons that run diagonally through the valleys in a southwesterly direction. The alluvium filled valleys are probably the result of multiple erosion cycles in addition to faulting and folding. Anticlines are predominant with only minor synclines present. Foothill-valley soils are principally alluvial deposits while the sur- rounding hills are granitic, showing various degrees of decomposition. The changes in surface slope and elevation have caused run-off water to carve deep canyons in many spots. San Diego and vicinity in the southern Peninsular Ranges is one of the most stable, least seismic, areas in the State. In contrast, the northern and eastern Peninsular Ranges constitute an area of extremely high earthquake frequency. The study area lies just south and west of the Elsinore Fault Zone, one of California's most active geological regions. The San Jacinto Fault lies about 45 miles to the northeast. None of the many recorded earthquakes which have been centered along this fault line has been much above a magnitude of 5-7 on the Richter Scale. A fault transverse to.the Elsinore Fault passes across Lake Wohlford and forms a southeasterly boundary of Escondido Valley. This region is located about 8 miles to the east of the study area. No epicenters of major earthquakes are known to have been located within or near the study area. Climate The weather of San Diego County, as in most of Southern California, is profoundly influenced by the Pacific Ocean and its semi-permanent pressure systems that result in a dry, warm summer and a wet, cool winter. The moder- ating influence of the ocean is felt along the coastal plain and coastal valleys, and the temperature range increases with distance inland. The coastal area receives 3,200 hours of sunshine per year, or about 73 percent of the maximum possible total, with amounts increasing inland. 2 Winter storms are infrequent within the County, with the result that sunshine percentages are about the same during the winter as they are during the summer. Along the immediate coast, sunshine percentages actually decrease slightly during the summer due to night- time and early morning cloudiness, typical of most of the California coast. Winds are generally light, and near the coast they reflect the large scale circulation of the nearby ocean area. Inland, however, local terrain is often the dominant.factor, and wind directions are likely to conform to the direction of the valleys and ridges. As in most mountainous areas, there is a tendency for the wind to move up the valleys during the day and down the hills anci valleys Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations 19 at night. Wind records are limited to those along the coast. Presented in Table 3-1 is a five-year record of wind taken at Oceanside, located directly north and Table 3-1. Wind Velocity and Direction° Directionb Speed (mph)b 4-15 16-31 32-47 Total Percent number of hourly observations N 690 35 5 730 1.7 NE 9,058 804 2 9,864 23. 1 E 4,246 170 0 4,416 10. 3 SE 1,433 74 1 1,508 3.5 s 1, 860 215 11 2,086 4.9 fNI 3,439 182 2 3,623 8.5 w 8,104 570 6 8,680 20.3 NW 5,279 867 18 6, 164 14. 4 Calm 5,690 13.3 Total 34, 109 2,917 45 42,761 Percent 79.8 6.8 0. 1 100.0 a Source: Climates of San Diego County, University of California Agricultural Extension Service, November 1970 b Recorded at Oceanside, California, from hourly observations during a 5-year period (1934-1938). adjacent to the study area. These data indicate predominately westerly and northeasterly winds. In general, wind speeds are light to moderate as almost eighty percent of these wind speeds fall in the range of four to fifteen mph. Climatic data for the mountain-valley region is presented in Table 3-2 Table 3-2. Climatic Data for the Mountain-Valley Region° b Temperature, 0 r Precipitation, in. b Mean Extremes Month Monthly Daily max. Daily min. High Low Mean January 54.5 67.0 41. 9 84 27 2.45 February 54. 1 66.0 42.3 89 27 3.83 March 56.7 68.8 44.6 92 29 2.33 April 60.0 71.2 48.8 90 32 1. 57 May 63.3 74.4 52. 1 95 38 o. 13 June 66.2 76.7 55. 6 88 41 o. 15 July 70.6 81.8 59.4 99 49 o. 01 August 71. 3 82.0 60.5 99 49 o. 19 September 69.2 81.0 57.4 107 39 0.32 October 65.0 76.8 53. 1 101 40 o. 92 November 59.6 73.4 45.8 96 30 1.09 December 56. 1 69.2 42.9 89 30 3. 53 Annual 62.2 74.0 50.4 107 27 16. 52 a Source: Climates of San Diego County, University of California Agricultural Extension Service, November, 1970. b Recorded at Escondido, California. Maximum 7.82 9.37 8.09 5.32 1. 58 0.60 o. 12 2.20 3.57 6. 18 5. 18 9. 17 32.64 20 Existing and Projected Planning Area Characteristics for a station in Escondido, which is located about 7 miles southeast of the study area. Monthly mean temperatures range from 54. 2°F in February to 71. 30F in August, and the annual mean temperature is 62. 2°F. Recorded extremes are 10 7°F in September and 2 7°F in January and February. Precipitation, occurring mostly during the winter months from December to March, has an annual mean of 16. 52 inches, while the greatest recorded monthly and annual precipitation values have been 9. 3 7 and 32. 64 inches, respectively. Climatic data for the coastal region are presented in Table 3-3 for a sta- tion in Oceanside. Monthly mean temperatures are slightly less extreme than the inland values, and range from 51 .9°F in January to 67 .2°F in August. Table 3-3. Climatic Data for the Coastal Region° o b b Temperature, F Precipitation, in. Mean Extremes Month Monthly Daily max. Daily min. High Low Mean Max. January 51. 9 61.2 42.6 85 25 1.96 5.74 February 52.7 61. 3 44.0 88 30 2.52 4.81 March 54.2 62.6 45.6 88 33 l. 60 3.73 April 56.9 63.9 49.9 93 37 0.96 2.87 May 59. 8 66.0 53.6 89 40 0.18 1.30 June 62.6 68. l 57.l 93 44 0.06 0.21 July 66.5 71.8 61. 2 82 48 0.02 0.22 August 67.2 72.9 61. 5 86 so 0. 10 l. 14 September 65.5 72.2 58.8 102 44 0. 13 0.62 October 61. 7 69.6 53.8 103 36 0.47 2.01 November 57.4 67.3 47.4 97 29 0.90 4.15 December 54.l 64.0 44.l 88 29 1.80 4.19 Annual 59.2 66.7 51. 6 103 25 10.70 13.69 a Source: Climates of San Diego County, University of California b ~:~:~~~~n ;t~~:=~s~::~~~~:fo:~i:o The annual mean temperature is 59. 2°F and recorded extremes are 102°F in October and 25°F in January. The relative stability of the coastal climate is reflected by the small difference between the mean and largest annual precipi- tation, 10.70 and 13.69, respectively. Monthly evaporation data are shown in Table 3-4 for a station at Lake Wohlford, which is located about ten miles east of the study area. Total annual evaporation is 59 .15 inches. Regional Air Quality Climatic conditions and topographic characteristics of an area to a large extent determine the susceptibility of that area to air quality degradation. Of critical importance is the presence of temperature inversions. Temperature inversions form an effective barrier against the vertical interchange of air and the upward dispersion of air pollutants. Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations 21 Table 3-4. Evaporation Data0 Month January February March April May June July August September October November December Total Evaporation (inches) 2. 19 2.41 3.36 3.97 5.88 6. 84 8.79 8. 18 6.85 4.65 3,45 2,58 59.15 a Source: Escondido Mutual Water Company for a 15-year period (1940-1954) of record at Lake Wohlford. Inversions in California are due to three major causes: chilling of air in con- tact with the ground due to the radiation of ground heat into space at night, which produces radiation inversions; the intru- sion of cold marine air beneath the war- mer air over the land along the coast; and, the general tendency for air along the entire coast and several hundred miles inland to sink toward the earth from higher altitudes. This latter inversion, a subsi- dence inversion, is present over almost all of California during most of the spring, summer a~d fall 3 • This subsidence inversion is per- sistent over the study area at an eleva- tion of about 2,000 feet, somewhat higher on the average than in the Los Angeles area. The persistent inversion condition, light winds and a high percentage of available sunlight combine to create a potential for the production of photochemi- cal air pollution in the area. Careful planning will be necessary to insure that this potential for adverse air quality is not realized. The State Air Resources Board has initially contributed toward the prevention of an air pollution problem by formulating the State of California Implementation Plan for Achieving and Maintaining the National Ambient Air Quality Standards. 3 In this plan, the State has discussed existing air quality, probable population growth, and the probable effects of the State's control strategy on ambient air quality. Although increases in pollutant emissions would be expected due to the Table 3-5. San Diego Air Basin Ambient and Projected Air Quality0 Projected National 1970 1980 Contaminant standard Level level Carbon monoxide, gb ppm 16 < 9 Nitrogen dioxide, ppm 0.05c 0.026 < 0.05 Oxidants, ppm 0.00d o. 50 < 0. 08 Particulate matter, ,ug/m3 60e 57 < 60 Sulfur dioxide, ppm <o.02C 0.01 < o. 02 a Source: The State of California Implementation Plan for Achieving and Maintaining the National Ambient Air Quality Standards, Air b Resources Board, 1972. 8-hour average c Annual average d 1-hour average e Annual geometric mean planned population growth in the air basin that includes the study area, the State Air Resources Board has concluded that nat- ional ambient air quality standards will be maintained by implementation of the State's emission control strategy. A summary of the present and projected am- bient air quality for the San Diego Air Basin is presented in Table 3-5. In order for ambient air quality to be maintained, the State Air Resources Board has stipulated that many significant measures to control contaminant emis- sions must be implemented. The State's strategy includes such actions as contin- uation of the State's current motor vehicle emission control program, elimination of carbon monoxide emissions from aircraft and ships, periodic vehicle emission 22 Existing and Projected Planning Area Characteristics inspections, conversion of one-third of the ga saline powered motor vehicles to gaseous non-polluting fuel, a reduction of motor vehicle use through use of public transportation, car pooling and changes in work schedules, control of the evapora- tion emission of organic hydrocarbons, regulation of the use and disposal of or- ganic hydrocarbons, regulation of the use and disposal of organic solvents, and the retrofit control of the fuel evaporative emissions from 1966 through 1969 model motor vehicles. The present air contaminant emissions in the San Diego Basin and those ex- pected to occur as a result of the planned growth of the area subject to the above mentioned emission controls are shown in Table 3-6. It is significant that imple- mentation of the State's emission control strategy will result in a decrease in the Table 3-6. San Diego Air Basin Air Contaminant Emissions0 Carbon monoxide Nitrogen dioxide Oxidants Particulate matter Sulfur dioxide Actual Projected Actual Projected Actual Projected Actual Projected Actual Projected Source 1970 1980 1970 1980 19 70 1980 1970 1980 1970 1980 Stationary 10 13 52 C 18 5 170 C 18.5 C Mobile 1530 160 160 C 219 19 26 C 16.2 C Total 1540 173 212 C 237 24 196 C 34.6 C Allowable 866 866 C C 47 47 C C C C a Source: The State of California Implementation Plan for Achieving and Maintaining the National Ambient Air Quality Standards, Air Resources Board, 1972. All units in ppm, except for particulate material ( µg/m3). b Projections valid only if the State's control strategy is fully implemented. c Estimate not included. Ambient air quality standards for these contaminants were not exceeded in 1970 and levels are expected to remain below those standards through 1980. emission of critical air contaminants and an improvement in air quality compared to 1970 levels. It follows that a wastewater management system designed to ac- commodate the planned growth of the area would not contribute to secondary ad- verse impacts on the area's air quality. Water Resources The principal sources of water in the study area are precipitation runoff, groundwater and imported water. The annual amounts contributed by each source vary and future quantities will depend upon population density, geography and climatological conditions. Irrespective of the above factors, imported water is the largest single source of water for the study area. Natural runoff in the study area results mainly from rainfall. Since the mid-\ 1940's, there has been a long-term reduction in the amount of precipitation, and therefore runoff, available for use in San Diego County. As a result, runoff, which once was a major portion of the area's water resources, now has been re- legated to a minor role in the overall water supply of the area. Historically, groundwater has also been an important source of water in the area. The utilization of groundwater supplies depends on its availability, which Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations 23 is a function of pumping costs and quality, the demand for water and the cost and availability of other sources. In recent years, the demand for water has progres- sively increased, while the availability of groundwater has decreased. Due to the impairment of groundwater quality in many areas and the ready availability of imported Colorado River water, groundwater has been relegated to a minor position as a source of water supply for the County. There are two well fields located within the study area. The first is located along the length of Buena Vista Creek, from the lagoon to the City of Vista. The second field is concentrated around Agua Hedionda Creek just east of the lagoon. The water table is relatively high in both well fields, with water levels in the wells never deeper than 25 feet from the surface. Water quality in these well fields is generally quite poor. Vvells along Buena Vista Creek produce water with a total dissolved solids (TDS) content of 1000-1500 mg/1, while the concentration of TDS in water from wells along Agua Hedionda Creek averages 1500 mg/1 and individual samples have been reported to contain as much as 2000 mg/1 of TDS. 1 The TDS consists primarily of chlorides of magnesium and sodium, indicative of sea water intrusion resulting from overpumping the groundwater basin. Water is imported to coastal San Diego County through the facilities of the Colorado River Aqueduct of the Metropolitan Water District of Southern California (MWD) and the First and Second San Diego Aqueducts of the San Diego County Water Authority (SDCWA). Since use of Colorado River water was initiated in 194 7, San Diego County has become increasingly dependent on this_ water source. The extent to which water requirements of the County have surpassed local avail- able supplies can be seen from the statistics of the San Diego County Water Authority, which supplies more than 80 percent of the water to users in the County. In the 1971-72 fiscal year, the total water use in all member agencies of the Authority amounted to 372,081 acre feet, of which all but 43,480 acre feet was Colorado River provided by the Authority. 4 In addition to present water imports to the County, MWD has contracted for over 2 million acre-feet of Northern California water from the State Water Project. MWD, serving the Los Angeles area as well as most of coastal San Diego County, will be the largest consumer of water provided through the California Water Project, using about 4 7 percent of the project's capacity. Approximately 5 percent of MWD' s entitlement will be used in San Diego County. 4 The problems of reduced runoff, groundwater mineralization, and increa sect environmental and financial costs of importing water supplies have resulted in several attempts to reclaim and reuse community wastewater in San Diego County. The Santee Project, where reclaimed water is being employed in a recreational lake program, is a notable example. Since conservation of water by water reclama- tion may result in savings of both financial and natural resources, a review of the alternative programs presently being studied and their future potential is of im- portance. The potential for water reuse within the study area was investigated in de- tail previously in the Encina Sewerage Survey. 5 As summarized in the above 24 Existing and Projected Planning Area Characteristics report, the greatest potential for water reclamation within the study area is agri- cultural use and land beautification. The potential of water reclamation for agri- culture, however, depends upon the rate of population growth within the study area, since the gradual transition from agricultural to urban land use dictates a decline in future irrigation requirements. It has recently been announced that a major oil refinery is tentatively plan- ned for a site overlooking Agpa Hedionda Lagoon. Developers of the refinery intend to explore the potential use of about 2 to 3 mgd of reclaimed water for cooling purposes. Other than the above use, the outlook does not appear favor- able for industrial use of reclaimed water in the study area. There is only limited potential for its use in recreation, and recharge of the groundwater with waste- water effluent is not practical. The potential of water reuse for domestic water supply is dependent solely upon the development of future water supply programs and possible technological advances, and hence has no present-day value. ENVIRONMENTAL SETTING An important aspect of alternative project evaluation concerns the assess- ment of potential environmental impacts. Such assessments should be made on the basis of a clear understanding of the existing environmental setting, including the immediate area of the projects and the regional aspects of the environment surrounding the project sites. Physical Features Most local streams which carry runoff from the various drainage basins flow into brackish water lagoons before flowing to the ocean. In the past, the effluent from wastewater treatment plants has been discharged directly into Buena Vista Lagoon. Wastewater discharged to lagoons would be modified by the natural bio- logical processes taking place within the lagoons, which act as natural oxidation ponds for the effluent. Nitrogen and phosphorus contained in wastewater are uti- lized in the growth of plant organisms such as algae. This process promotes algal blooms and eutrophication causing the formation of unsightly floating mats. In shallower areas, wastewater would fertilize a lush vegetative growth which pro- vides a rich food source for birds and a habitat for mosquito and midge larvae. In deeper waters, organic matter undergoes anaerobic decomposition with the produc- tion of hydrogen sulfide, a typical source of unpleasant odors. Buena Vista Lagoon. This lagoon is situated between the cities of Ocean- side and Carlsbad and has an area of approximately 350 acres of which 220 acres are water. It is divided into five sections by the Santa Fe Railroad, Hill Street, Interstate 5 and Jefferson Street. The main bodies of the lagoon contain open brackish water (4,000 ppm TDS) and are from a few inches to five feet deep. The portion of the lagoon which is located east of Jefferson Street is a marshland over- grown with tall reeds and bullrushes which serve as nesting areas for birds. The ea stern end of the lagoon has been filled for the May Company Shopping Center. Existing stores and parking areas of the Center do not cover the western portion of the fill and no construction is occurring in that area. Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations 25 South and east of the lagoon is Hosp Grove, a large stand of Eucalyptus trees set around a small valley. This grove is currently being developed into a single and multiple dwelling unit residential area by a Carlsbad construction company and is not included in the proposed Buena Vista Wildlife Preserve. The lagoon is surrounded by bluff-top residential areas of Carlsbad and Oceanside. Buena Vista Creek, which empties into the lagoon, drains an area of approximately 22 square miles and flows nearly year round due to rising ground- water and irrigation runoff. The lagoon has been closed to the sea for some time and has no tidal fluctuations, thereby causing a relatively low salt content. Prior to September 1965, the Vista Sanitation District and the City of Carls- bad discharged more than two million gallons per day of secondary wastewater treatment plant effluent into the lagoon. This heavy input of nutrients led to pro- lific algal blooms and accompanying problems of eutrophication, odors and un- sightliness. Floating mats of filamentous algae appeared and formed rotting scum on the shores and bottom. Insect control measures of the San Diego County De- partment of Public Health were almost nullified by these conditions. After September, 1965, wastewater was conveyed to the Encina WPCF which was jointly constructed by Vista Sanitation District and the City of Carlsbad. Since that time, the only wastewater to enter the lagoon has been a small quantity of secondary effluent discharged from the City of Oceanside's Buena Vista Treat- ment Plant during emergencies. Natural elimination of the nutrient load has been very slow due to the essentially static conditions of the water, but definite pro- gress has been made. The lagoon has not been opened to the sea , so that the brackish water environment and bird feeding ground would not be disturbed. The natural cleansing process has probably been slowed by the input of waste nutrients from the thousands of birds that live in the lagoon. The lagoon is a favorite rest- ing station on the Pacific Flyway as it is one of the few remaining fresh water lagoons in southern California. 6 Until recently, much of the lagoon and surrounding lands were in private hands. Critical portions on either side of Interstate 5 were owned by the Nature Conservancy and by the Buena Vista Lagoon Association. These groups recently turned the area over to the State of California as part of the Buena Vista Wildlife Sanctuary. A portion of the land in the eastern end is owned by a developer who wants to fill it and establish a shopping center. Approval of the development by Oceanside, however, has been blocked by the Audobon Society and other conser- vationists. Buena Vista Lagoon will be preserved as a bird sanctuary under the State Park System as recommended in the Buena Vista Lagoon Study of 1966 and will therefore remain a fresh water lagoon and bird habitat. Careful study should occur prior to any construction on the shores surrounding the lagoon. Agua Hedionda Lagoon. Agua Hedionda is a relatively deep, salt water la- goon located south of the developed portion of the City of Carlsbad. San Diego 26 Existing and Projected Planning Area Characteristics Gas and Electric Company (SDG&E) owns the lagoon and uses it primarily as a cooling water intake and settling basin for the Encina Power Plants. The lagoon covers about 500 acres,of which 230 acres are water,and is divided into three sec- tions by the Santa Fe Railroad and Interstate 5 embankments. The mouth of the lagoon is maintained at a depth of 12 to 13 feet and kept open to the sea. Two short jetties about 250 feet apart protect the deep opening, while the entire lagoon has been dredged to a depth of at least six feet by SDG&E in order to provide a sufficient tidal prism to keep it open. During the dredging operation, four million cubic yards of sediment were removed and placed on the nearby beach. The lagoon is currently undergoing moderate recreational usage. Although SDG&E does not allow swimming or boating in the seaward portion of the lagoon, facilities for fishing have been provided. The two inner sections of the lagoon are used for swimming and boating, while the YMCA Day Camp is located on the north shore of the center portion of the lagoon directly across from the Agua Hed- ionda pumping station. A residential area of the City of Carlsbad is located north of the lagoon, while agricultural land devoted primarily to tomatoes borders much of the southern portion of the lagoon. Marshlands which extend east of the dredged portion of the lagoon have been the subject of studies which have investigated the possibi- lities of turning this area into a residential community and small boat harbor. Agua Hedionda Creek which empties into the lagoon drains an area of slight- ly over 2 8 square miles. Since the watershed area is quite small, the sand on the bottom of the lagoon is exceptionally fine. Soil samples indicate a range from beach sand to fine clays with larger rocks and cobbles found in the outer portions of the lagoon. Agua Hedionda Lagoon is a good example of the benefits which can be ac- crued in a lagoon by maintaining an opening to the sea and preventing wastewater input. The large tidal prism created by dredging and thorough tidal flushing, provides a good water quality and a rich marine ecology. Studies indicate that there are many varied species of mollusks in the lagoon. Beds of eelgrass, an important source of duck food, have colonized some areas of the lagoon. Due to the extremely stable ecology of the lagoon, no ecological problems are foreseen with any future development of the area. There may be some pollution from motor boat traffic but a study of this problem in San Diego Bay indicates that it will probably not be significant. 6 Biological Systems and Inhabitants Bays, estuaries, lagoons and marshes are rich spawning grounds for aquatic life. Cultivated by tides and fertilized by their own decaying vegetation, tide- lands can produce exceptional quantities of plant growth and can support a great variety of estaurine organisms. Wetland productivity is enhanced by the extremely short life cycles of most of the smaller inhabitants. Some species of bacteria live only ten minutes before dividing, and some insects, crustaceans, and fish may live only a few weeks before becoming prey. In the lagoon or marsh habitat, there Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations are fei trees or large animals to take nutrient supplies out of circulation for years. 27 The construction of the AT&SF Railroad was the first man-made project to interfere with the natural lagoon ecology, by altering the tidal-current patterns. The normal mixing of waters of different salinities creates a "nutrient trap" of food substances which, along with oxygen, are carried by the tides to the plants and animals of the estuary. Waste products from decaying or oxygen-using or- ganisms are either assimilated or removed by the flushing action of the two daily tides. For this reason, a flowing lagoon is generally more productive than a blocked system. If the flushing action of the tides is destroyed or altered, water quality can be degraded easily and wildlife and vegetation can be threatened. Vegetation. Salt marsh plants are generally low-growing and lacking in brightly colored flowers and are an example of ecological adaptation. These plants exist midway between the marine environment of seaweeds and the land environment of the upland scrub. This halophytic vegetation has evolved the ability to cope with both salt-water submergence and exposure to the sun. The success of the salt-marsh plants lies in their ability to thrive in highly saline soil. Lagoon plants tend to establish themselves into groups or communities with- in contoured zones or belts of vegetation that correspond with average tide levels. Marshes have three major zones: submerged, littoral and maritime. The sub- merged zone is continuously underwater, while the littoral zone includes all areas which are covered by tidal waters at any time. The maritime zone is the area where vegetation is influenced by the salt air and spray. Submerged Zone. The plants of the submerged zone are extremely impor- tant as food and shelter for vertebrates and invertebrates. Some common species are absent from the two lagoons under consideration, probably as a result of the changes in concentrations of dissolved oxygen and salt. Several species can over-produce, die and cause odors, but this is avoided in Agua Hedionda Lagoon due to the tidal flushing action. Four kinds of plants are usually found in this zone: The eel grass or Zostera, the ditch grass or Ruppia and algae such as Enteromorpha and Ulva 6 • The eel grass now forms dense stands along the bottom of Agua Hedionda Lagoon. Zostera and Ruppia are absent from Buena Vista Lagoon due to the low and fluctuating salinity content of the closed lagoon, while various algae species are prevalent in Buena Vista Lagoon due to the nutrient content of the waters. Littoral Zone. The littoral zone is that area covered and uncovered by tides. Due to the relatively steep slopes of Agua Hedionda Lagoon, there is little intertidal salt marsh area around the lagoon. Only on the eastern end of the lagoon is there a significant littoral area. Stands of pickleweed or Salicornia exist in this area. There is no littoral zone in the Buena Vista Lagoon due to the lack of tidal action, but the low salinity supports small stands of bullrushes or Scirpus robustus and cattails or Typha latifolia near the creek outlet. These areas are used as nesting and feeding areas by ducks. 28 Existing and Projected Planning Area Characteristics Maritime Zone. The maritime zone is not inundated by tides, but the vegetation must have the ability to grow in soil made saline by salt spray. This zone supports a diverse flora and is used extensively as a habitat by birds and animals. However, neither Agua Hedionda nor Buena Vista Lagoon exhibits a true maritime zone and surrounding vegetation is more typical of the coastal sagebrush maritime zone. 7 Bordering Buena Vista Lagoon along Jefferson Street are sparse stands of deciduous trees interspaced with conifers. Animal Life. All three vegetation zones support some forms of animal life in a coordinated, symbiotic ecological system. Animals in one zone feed off of plants and animals in another zone, while plants thrive in the nutrient deposits left by animals in all three zones. The plant growth further encourages animal growth which in turn means more nutrient material for the ecosystem. In the salt marsh, as in few other ecological systems, nature has interrelated all plants and animals in a rapid, extremely adaptable and interesting dependency. Although the animals of the salt marsh can be classified according to the general vegetation areas in which they reside, there are significant overlapping characteristics, particularly in feeding habits. For this reason, the animals will be discussed according to biological types, with emphasis on interrelationships and dependency on physical factors of the surrounding environment. Invertebrates. Invertebrates are important in the ecology of the lagoon. They feed on the waste nutrient substrate and keep the bottom waters clean. They also act as an important food source for larger vertebrates such as shore birds, ducks, and fish. Based on past studies of species abundance, stomach contents of birds and fish, and literature studies, it has been determined that the inverte- brates are the most important fauna in the lagoons. Only the major invertebrates such as mollusks, worms and larger crustaceans will be considered here. The discussion is limited to the above animals due to the variety of microinvertebrates, as well as to the lack of concrete data available on these species relative to the specific lagoons in the study area. Past studies have determined that mollusc distributions are limited by five factors: salinity, oxygen content, temperature, available substrate, and velocity of tidal flow. Salinity is the single most important factor because mollusks need to live at or around sea water salinities, alone precluding any significant mollusc population in Buena Vista Lagoon. However, mollusks are numerous in Agua Hedionda Lagoon and many species have been identified. When SDG&E opened this lagoon to the sea, the number of mollusc species increased from zero to 74. Mollusks have protective mechanisms which allow them to endure brief periods of exposure to low salinities, such as fresh water flooding during winter periods. Temperature and oxygen content do not appear to be the limiting factors for the mollusc population in Agua Hedionda Lagoon, but, since the lagoon is open, the substrate availability and flow velocities determine the location of molluscs. Each mollusc species is adapted to feed off of a different type of substrate in a Improvement and Enlargement of tlle Buena V 1sta and Agua Hedionda Pumping Stations 29 different area of the lagoon. No two mollusc species compete for the same food source. Mollusks thrive on sandy bottoms and avoid muddy bottoms because the silt interferes with their filter feeding apparatus. For these reasons more types of mollusks, clams, scallops, and shellfish live in Agua Hedionda Lagoon than in other lagoons of San Diego County. Insects. Insects are common in the lagoon and marsh environments. Kelp flies, mosquitos, dragonflies and midges can be found among the vegetation while their larvae inhabit the more quiet shallows. The San Diego Health Department uses pesticides to control mosquitos in some coastal lagoons but is not currently conducting regular operations in either lagoon in the study area. Buena Vista Lagoon has been left in its natural state as a bird habitat and Agua Hedionda has enough flow from tidal fluctuations to minimize the mosquito problem. Dragonflies and beetles inhabit the fresh and brackish waters of Buena Vista Lagoon, while bees, spiders, wasps and butterflies can be found in the transition and upland marsh regions. Due to the lack of solid ground, most land based insects such as ants and termites appear to be absent from the salt marsh and lagoon environments. Fish. Agua Hedionda Lagoon supports many species and is a natural nursery- sanctuary for young fish. Halibut, Stripped Bass and Yellowtail are common oceanic varieties found in the lagoon, and Killifish are also quite abundant. Pipe- fish, Topsmelts and Mud suckers also inhabit the lagoon, along with Gobys, Grunion and Sculpin. Buena Vista Lagoon is not similar, since it is closed to the ocean. Its brackish, oxygen deficient waters do not support as much aquatic animal life, although birds and some small brackish-water fish such as sunfish and catfish, and amphibians such as frogs, salamanders, and newts are present. Reptiles and amphibians do not predominate except near the discharge point of Buena Vista Creek, however, due to the lack of fresh water wetlands, ponds and streams. Birds. Birds presently form a most attractive biological feature of the coast- al lagoons. The majority of the birds that are seen along the coast of San Diego County migrate southward along the Pacific Flyway during the fall and return during the spring to northern breeding grounds. Many of these birds depend upon the lagoons and marshes for food and resting areas. Shore birds can frequently be observed probing the mudflats for worms, clams and insects at low tide, or resting on the salt pan areas at high tide. Some common shore birds are plovers, turn- stones, snipes, sandpipers, willets, and dowitchers. Wading birds seek fish, mollusks and amphibians in shallow waters. Diving birds, such as cormorants, grebes, terns and gulls are commonly seen in deeper tidal channels and near lagoon entrances. Herons and egrets are relatively common in all coastal lagoons along with several species of ducks, and a few geese. Although all of the above mentioned birds are commonly found in both lagoons, they commonly nest only in the sanctuary of Buena Vista Lagoon. Mammals. Most of the terrestialmammals that frequent the lagoons and marsh areas are nocturnal in their activities. Although they live in or adjacent to this habitat which includes the grasslands, brush and dry land areas, they venture 30 Existing and Projected Planning Area Characteristics out only to forage during periods of low tide. The small mammals include three species of rabbits, and various rodents including mice, ground squirrels, wood rats, gophers, moles, and shrews. Larger mammals include stripped and spotted skunks, possums, coyotes and foxes. Raccoons are especially prevalent around the borders of urban communities and thrive on solid waste products of civilization. Only the smaller mammals are found at Agua Hedionda Lagoon, while all of the above mammals are usually seen in the upper reaches of Buena Vista Lagoon 6 , particularly around Buena Vista Creek. Endangered and Rare Animal Species. Changes in available habitat, over- harvesting, and the impact of chemicals released to the environment by man, have reduced the populations of some animals in southern California to levels that are dangerously near extinction. Regulatory agencies and informed laymen who realize that each generation is a trustee of the environment for succeeding generations rightfully show concern when the human use of the environment endangers the existence of other animals. Southern California species that are considered en- dangered by the State Department of Fish and Game include the migrant Blue, Humpback and Pacific Right Whales and the resident Southern Bald Eagle, American Peregrine Falcon, Light-footed Clapper Rail and the California Clapper Rail. Summer-visiting species that are considered endangered include the California Least Tern (less than 30 pair in existence) and the Brown Pelican. Rare species include the Guadalupe Fur Seal, the Gray Whale and the California Black Rail. Buena Vista Lagoon is a nesting area for Rails and Terns, certain species of which, as mentioned above, are considered to be endangered. According to data accumulated by San Diego County, there are no endangered species which nest in Agua Hedionda Lagoon7 • Regional Plans for the Environment Environmental quality is the subject of many Federal, State, Regional and County policies and plans; some of which are described here for general reference. Federal policies of concern to North San Diego County include funding for facility construction and environmental quality enforcement measures. Funding programs of particular interest include the EPA construction grant program which presently can support up to 7 5 percent of the capital cost of wastewater treatment and dis- posal facilities and certain wastewater transmission facilities. SWRCB Clean Water Bond Issue matching funds can bring the grant total to 87. 5 percent. Cer- tain other wastewater transmission facilities, not eligible for State-EPA grants, are eligible for grant support from the Department of Housing and Urban Develop- ment. HUD grants can support up to 50 percent of the construction costs of these facilities. State policies are contained in the Interim Water Quality Control Plan for the San Diego Basin8 published by the California Regional Water Quality Control Board in June, 19 71 • This document serves as the Basin Plan for the San Diego Basin which extends along the Pacific Ocean from Laguna Beach to the Mexican Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations 31 Border and includes most of San Diego County. State plans for maintaining air quality have also been developed and serve as a general basis for any regional planning decisions • Local Noise Environment A direct environmental impact of waste disposal and treatment is the impact of pumping station operation on the local noise environment. Past environmental impact noise studies of similar sites indicate that the presence of a major fr~eway, such as Interstate 5, is the dominant factor in the local noise environment. Mean or average noise levels monitored along Interstate 5 in November, 19 71 dur- ing daylight hours varied between 55 and 61 dBA, depending upon the percentage of heavy trucks in traffic. These noise levels were high enough to completely mask any noise produced by wastewater pumping stations during normal operation. Currently both pumping stations produce noise levels which are barely discernable outside of the existing structures when all exterior doors are closed. This con- dition will not change noticeably after the proposed modifications are completed. ECONOMIC ACTIVITY Agriculture, tourism and the military have an impact on economic activity in the study area. Agriculture is San Diego County's fourth largest industry, in addition to being the oldest. Areas of tillable agricultural land in the County are located principally on the western coastal plain. The amount of irrigated agricul- ture in terms of crops for each drainage basin encompassing the study area are listed in Table 3-7. About 17 percent of the land is devoted to irrigated agricul- Table 3-7. Agricultural Land Use0 Drainac e basins, acres Buena Agua Classification Vista Hediondif Total Irrigation agriculture Alfalfa 0 0 0 Pasture 80 140 220 Citrus and sub-tropical 1,220 1,370 2,590 Truck crops 340 720 1,060 Field crops b 10 10 Deciduous fruits and nuts 10 90 100 Small grains 0 0 0 Vineyards 30 0 30 Subtotals 1,680 2,330 4,010 Fallow 100 330 430 Included non-water service area 130 190 320 Gross irrigated agri- culture 1,910 2,850 4,760 Non-irrigated agricultrue 370 840 1,210 Total agriculture 2,280 3,690 5,970 a Source: San Diego County Land and Water Use Survey ,Department of Water Resources ,1967 b Less than 5 acres c Includes area upstream of study area ture, accounting for approximately 5 per- cent of the irrigated agricultural lands in San Diego County. There are many diverse leisure time activities for residents and tourists within the study area, many of which are water-oriented due to the presence of the Pacific Ocean and the quiet embay- ments and estuaries. Both of the lagoons within the study area provide recreational benefits, and only development of the lagoons for purposes other than recrea- tional would prevent continued use for that activity. At present, Buena Vista Lagoon is used for fishing and wildlife refuge, while Agua Hedionda is used for boating, fishing and water-skiing. Camp Pendleton, immediatAly north of Oceanside, is the largest Marine Corps traininq establishment in the nation: the shoreline affords opportunity for 32 Existing and Projected Planning Area Characteristics training in landing procedures from ocean vessels, while the inland topography is suitable for training in the use of land vehicles. The recent increase in the assessed valuation of the two agencies in the study area emphasizes the rapid growth which this area has experienced. The total assessed valuation of the Vista Sanitation District and the City of Carlsbad has increasE:-d about twofold relative to the 1965-66 total assessed valuation of $106,531,960. The principal commercial centers in the study area are located in the down- town sections of the cities and at the May Company Center located in the Buena Vista drainage basin in the City of Carlsbad. Serving the Tri-Cities of Carlsbad, Oceanside and Vista, the center contains department stores and many related developments. Outside the metropolitan core of San Diego, industrial developments have been slow to expand. In recent years, however, assembly plants and light manu- facturing industries have started to locate in outlying parts of the County. Land adjacent to major transportation links has been reserved for industrial development by the planning department of each community. Due to the relatively small amount of industry at present, however, much of the local working force is employed out- side of the study area, commuting to either Escondido, Oceanside, Camp Pendleton or San Diego. It is expected, however, that future development of the presently vacant industrial lands will shift the working orientation of the labor force, at least to some extent, to the study area. LAND USE AND POPULATION In the growth of any urban area, the gradual change in land use from rural or agricultural to residential, commercial or industrial activities inevitably pro- duces a demand for adequate municipal services. Because of the long useful life Table 3-8. Existing Land Use0 of sewerage facilities, estimates of Draina e basin, t ercent Buena Agua Classification Vista HediondJ: Total Urban and suburban Residential 26.3 10.4 18.4 Commercial 1.9 0.2 1.0 Industrial 0 0 .1 • I Unsegregated urban and suburban area 1.7 0.7 1.2 Non-water service area 12.2 4.5 8.4 Irrigated agriculture 13.7 14.4 14.0 Non-Irrigated agriculture 2.7 4.2 3.5 Native vegetation 12.0 6.5 9.2 Unclassified 29.5 59 .o 44.2 Total 100.0 100.0 100 .o a Source: San Diego County Land and Water Use Survey, Department of Water Resources, 1967 b Includes area upstream of study area future population in terms of both total numbers and areal distribution are essen- tial to proper planning of those facilities. Future land use and population projections presented herein are based on work under- taken for the Encina Sewerage Surveys and on discussions with planning personnel in both Carlsbad and Vista. Existing Land Use As previously mentioned, lands within the study area have historically been devoted to agriculture. Various or- chard, field and dry farmed crops are now grown on approximately 6,000 acres representing 1 7 percent of the two basins which encompass the study area. The crop distribution on these agricultural lands for each drainage basin has been ~· ~ I 11~ •. ·,,.,.. u,,,,. VJ ".,, ,-(-'-, j, ::.-.. ~ C• 0 r, 2000 ,· -,. n .,. ~ .,. <' SCALE IN FEET 2000 4000 . .( -l• ' 0000 .. --'fr, r ~- ... ~ ' \ ' .., , ,.. ( I w ' ,, _;..,.. .,. , i I ~ ' ... •· I I i' ,I ' I ,;t ·I -"'<---•, 1 ~ ')I:;_- ,, ~ c::J -~ rzm ~ ~ CJ Fig. 3-2. LEGE N D STUDY AREA BOUNDARY LOW DENSITY RESIDENTIAL MEDIUM DENSITY RESIDENTIAL HIGH DENSITY RESIDENTIAL COMMERCIAL ~ INDUSTRIAL -,, PARK NEGLIGIBLE DEVELOPMENT land Use at Planne .. 'f ~ < l (t Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations presented previously in Table 3-7. 33 Presently, approximately 29 .1 percent of the land in the basins is developed, as shown in Table 3-8. This development is primarily centered around the estab- lished communities of south Oceanside, Vista and Carlsbad. The remaining portion of the study area is undeveloped. Future Land Use The study area portion of the figure in the Regional Survey which indicated planned maximum development is presented here as Fig. 3-2. The San Diego County General Plan for 1990 was used as a guide for future land use data in this report. Deviations from the General Plan were made by referring to: (1) more detailed land-use plans of Vista and Carlsbad and (2) topography. It must be emphasized that the saturated land use plan has been developed only for use in estimating future population and represents the use of land when all the desirable areas have been developed. In order to conserve much of the open space, it is advocated that good planning procedures be followed in pre- venting mass development of the area. Subsequent to formulation of the data contained herein, a new detailed land use plan has been developed for Carlsbad and is near adoption. The new plan, however, generally conforms to the pattern of development shown in Fig. 3-2. Changes in population which resulted from the new plan have been incorporated into the projections discussed in a latter section. Categories of land use presented in the figure may be described as follows: Low density residential consists of single family dwelling areas; this land use classification provides for single family estate developments of a spacious semi-rural character, under hillside conditions, where provision is made for limited agricultural uses. Medium density residential provides for conventional detached single family dwelling units on small lots combined with some attached single family dwellings. High density residential provides for higher density cluster housing and apartments, concentrated primarily in the urban centers. Commercial provides for all classes of commercial use including regional and local shopping centers, and central commercial districts. Industrial provides for all classes of industrial use including light to medium manufacturing, processing, and warehousing. Parks provides for parks, golf courses. 34 Existing and Projected Planning Area Characteristics Population Growth No exact methods are available for predicting future changes in population. In fact, it is more realistic to regard the results of population studies as simply projections rather than predictions. Several techniques are available for guides in the making of population projections, all of which must be used with dis- cretion. Plotted curves of population versus time may often be extended by visual observation with some degree of accuracy. Another common procedure is com- parison with forecasts for similarly situated areas or with predictions for larger areas which include the study area. As stated in the Regional Survey, review of the environmental characteris- tics of the study area indicate that its population growth within the next 30 years will be influenced primarily by the same factors which have been responsible for its present and past growth. Under these circumstances a mathematical pro- jection basecl won past trends and future possibilities, such as the logistic curve method 1 , was believed appropriate for the study area. Since 19 71 , following the publication of the Regional Survey, north San Diego County has experienced a rapid rate of growth. Based on recent rates of growth and forecasts of immediate construction, additional projections have been made for population growth in Vista and Carlsbad. Recent discussions with representatives of the agencies pertaining to treatment plant capacity indicate that Vista and Carlsbad anticipate 48,000 and 40,000 people within their res- 98 97 96 95 .. 92 90 I I I I I I I I . BUENA VISTA V DRAINAGE BASIN , / y / ~ =~ / ,, I / pective service areas by 1984. Based on these estimates by the agencies, popu- lation projections for Vista Sanitation District presented in the Regional Survey are considered appropriate for purposes of this report. Previous projections for Carlsbad, however, have been updated proportionally to reflect new population growth rates anticipated for the City in ,, ~ ,o ~ 4.5 ~ ;~ ~ ,o 2, ~ 20 ,._ "' ,, s ~ 10 8 7 6 , • , 2 I 1940 I ,, ,, ,, / I/ / / / ,, ,, ,, I,'" / / L '-AGUA HEDIONDA ,, the recently adopted master land use plan. Most of the service area population of Vista Sanitation District is served /' DRAINAGE BASIN - by the Buena Vista and Agua Hedionda pumping stations, whereas only a portion of the future population in the overall Carlsbad service area will be served by the two pumping stations • I , I _.,. 1..,...- I I I I I I 19$0 l!l60 l!ITO 1980 1990 2000 20/0 YEAR fig. 3-3. Logistic Curve Analysis I The results of the logistic curve 2020 analysis are presented in Fig. 3-3 and the corresponding population projections are shown in Fig. 3-4 • Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations 35 110,000~-~--~--~--~---,------, The percent of saturation population taken from the logistic curve for any given year is assumed to be the percent of saturated land use as well. The projected popula- tion to be served by Buena Vista and Agua Hedionda pumping stations in the year 2000 is about 99,000 and 144,000, res- pectively. It should be recognized, how- ever, that urban development may occur /00,000 1950 ---I BUENA VISTA DRAINAGE BASIN ---2 CITY OF VISTA -•• -3 CITY OF CARLSBAD ---4AGUA HEDIONDA DRAINAGE BASIN 1960 1970 1980 rEAR I 1990 2000 Fig. 3-4. Projected Population 2010 at a faster or slower rate than anticipated. These data, therefore, are not presented as a prediction, but rather as a basis for various alternatives. 36 CHAPTER 4 EXISTING AND PROJECTED WATER AND WASTEWATER CHARACTERISTICS A major task in the development of a wastewater management study is the evaluation of existing water supply and wastewater characteristics to determine their present and future interrelationships. Accordingly, available information pertaining to water supply and wastewater have been analyzed in this chapter. WATER SUPPLY The characteristics of natural waters and water supply systems, the quanti- ties of water involved in consumption, and the physical and chemical quality of these waters are presented in this section. The mineral character of the water supply in any area has an important effect on wastewater characteristics and establishes background concentrations of inorganic constituents in wastewater. During use, a mineral increment and other constituents are added to the water. The resulting quality of the wastewater determines the types of wastewater treatment that are necessary and can significantly affect the feasibility of various disposal and reuse methods. Table 4-1. Chemical Characteristics of Colorado River Watera Constituentb 1971-72 1972-73 Mean Mean Calcium (Ca} 88 85 Magnesium (Mg) 33 31 Sodium (Na) 111 109 Potassium ( k) s.o s.o Bicarbonate (HCO3) 148 149 Carbonate (CO3) l .0 1.0 Sulfate (SO4) 327 310 Nitrate (NO3) 1.3 0.7 Chloride (Cl) 97 94 Fluoride (F) 0.4 0.4 Silica (SiO2) 8.0 7.5 Hydrogen ion, pH 8.3 8.3 Specific conductance, micromhos per cm 1,180 1,140 Percent Sodium 40 41 Total hardness as CaCO3 355 340 The water sup ply for the study area is principally Colorado River water ob- tained from the Metropolitan Water Dis- trict (MWD) through the San Diego County Water Authority (SDCWA). The only supplemental supply of water to the study area is obtained by Vista Irrigation Dis- trict from Lake Henshaw in quantities de- pendent on rain fall and runoff during the winter months. As is common with most river systems the quality deteriorates as it moves downstream because of evapora- tion and return flows from irrigated lands and urban areas. This degradation of quality is particularly pronounced in the Colorado River because of high evapo- transp iration losses and very low tribu- tary inflows in the lower reaches. As a result, Colorado River water is high in -------------'----~---total dissolved solids (TDS), hardness, Total dissolved solids 746 718 a Source: San Diego County Water Authority b Concentrations are expressed in milligrams per liter unless noted otherwise sodium and sulphate concentrations as shown in Table 4-1. High concentrations of these minerals make this water of Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations 37 marginal quality for domestic and industrial purposes. Moreover, after additional contributions of solids from domestic, commercial and industrial use the water has 1 ittle value for reclamation without demineralization. No softening facilities are now planned by water supply agencies within the study area. Consequently, future changes in concentration of minerals in wastewater will be in approximately the same proportion as changes in TDS concentration of the water source. Northern California water is expected to reach San Diego County in 1975 and is anticipated to be of significantly better mineral quality than Colorado River water. Chemical concentration estimates and objectives of the California Department of Water Resources indicate that the water will be of excellent quality for irrigation, general urban, most industrial uses, and for re- clamation and reuse. Water supplied to the consumer in 19 7 5 and thereafter, will no doubt be a blend of Colorado River water and northern California water. Since precise quality of water from the latter source is unknown and since the policy on blending ratios has not been established, precise chemical values of dissolved solids in domestic wastewater after 1974 are presently undeterminable. WASTEWATER CHARACTERISTICS Design of facilities for the collection, treatment and disposal of wastewater is dictated primarily by the loadings estimated to be imposed upon them at some future time. In developing such estimates, it is necessary to determine unit quantities for the components affecting both the volume of wastewater and its strength and composition. Because characteristics may vary from one community to another depending on the physical and economic environment, unit quantities for design purposes should be based on the evaluation of the characteristics in the particular area under study. For the most part, therefore, the criteria pre- sented have been developed by evaluating existing records of wastewater quality and quantity. Wastewater Composition Wastewaters from Vista Sanitation District and Carlsbad, as well as waste- water from the other Encina Joint Power agencies receive primary treatment at the Encina Water Pollution Control Facility (WPCF). Average annual influent concen- trations of five-day biochemica 1 oxygen demand (BOD 5) and suspended solids shown in Table 4-2 are in the range expected from residential communities with little industrial activity. The BOD5 and suspended solids of raw wastewater influent to the Encina WPCF averaged 144 mg/1 and 188 mg/1, respectively, in 1973. Industries which are presently discharging wastewater, other than domestic, to systems in the study area are listed in Table 4-3. Quantities of wastewater and the primary pollutants contained therein are also denoted for each establishment. It is anticipated that industrial development in the study area will keep pace with the expected increase in population. At present, the three largest industrial dis- chargers, con tribute only about 1. 4 percent of the tota 1 wastewater flow in the study area. 38 Existing and Projected Water and Wastewater Characteristics Table 4-2. Influent and Effluent Concentrations of BOD, and Suspended Solids at Encino WPCF, mg/1 Biochemical oxygen demand Suspended solids Year Influent Effluent % Removal Influent Effluent % Removal 1968 254 131 48.2 255 87 65.9 1969 215 113 47.4 212 81 61. 8 1970 156 96 38.5 178 79 55.6 1971 150 93 38.0 188 87 53.7 1972 156 95 39. 1 166 80 51. 8 1973 144 77 46.5 188 67 64 .4 1974a 155 75 50.0 205 68 68.0 a Includes data through July, 1974. Table 4-3. Industrial Waste Dischargers to Encino WPCF Average Major groupb Industry Location flowa (gpd) Wastewater characteristics Number Name Culligan Soft Carlsbad 27,000 Rinse water; pH = 7 • 8, suspended 39 Miscellaneous Water, Inc. solids -68 mg/1 c Vista Meat Vista 4,100 Rinse water from meat slaughtering 20 Food products Packers process; BOD = 1, 580 mg/1, sus- pended solids =1, 260 mg/1, grease = 192 mg/1 C Rayne Soft Vista 27,000 Rinse water; pH = 7 • 6, suspended 39 Miscellaneous Water, Inc. solids = 29 mg/1 c ~stimated average flow rates converted from cubic feet per month to gallons per day by assuming a 2 2-day work month. ~ajor group of Division D, Manufacturing Industries of the Standard Industrial Classification Manual, Federal Bureau of the Budget, 196 7. 93ased on 8-hour composite samples. At the Encina WPCF removal of BOD5 averaged 46. 5 percent and removal of suspended solids averaged 64. 4 percent in 1973.. The results of the monitoring program required of the Encina WPCF discharge to the ocean by the RWQCB are shown in Table 4-4. As the table indicates, the waste discharge was consistently in compliance with the discharge requirements outlined previously in RWQCB Resolution 63-Rl. New waste discharge requirements were adopted by the RWQCB in May, 1974, serving also as the National Pollutant Discharge Elimination System (NPDES) permit. These requirements embody recent Federal and State laws which necessitate secondary treatment by July, 1977. The Encina WPCF will have to be modified to meet the required effluent quality. Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations 39 Wastewater Volume Table 4-4. Comparison of Encino WPCF Effluent In the design of facilities for the Quality with Wastewater Discharge Requirements ==========.======;:====== collection, treatment and disposal of Average effluent Discharge quality requirements concentr1ion Effluent constituents mg/le mg/1 Biochemical oxygen de- mand, 5 day at 20°c Annual mean none 144 Maximum none 189 Total suspended solids Annual mean 125 188 Maximum 150 237 Grease Annual mean 40 36 Maximum 50 113 Gross heavy metals (total concentration of cadmium, hexa- valent chromium, copper, lead, nickel and zinc) Annual mean 2 1.36 Maximum 5 1.61 Bioassay, 24hr.TLm, percent d Annual test 9 Coliform bacteria MPN/ml Annual mean none d Synthetic detergents as MBAS Annual mean none d pH, units Annual mean none 7,3 a As per RWQCB Resolution 63-Rl b During the year January 1972 through December 1972 c Except where noted d Not available Table 4-5. Average Daily Wastewater Flow Rates to Encino WPCF0 , mgd Vista Sanitation City of Encina Year District Carlsbad WPCF 1968 1. 354 0.989 2,417 1969 1. 695 1. 109 3.494 1970 1. 777 1. 283 3.823 1971 1. 869 1. 505 4.632 1972 2.087 1.417 5.082 1973 2.467 1. 545 6. 131 a Flows are based on monthly averages for June of each year. wastewater, dry weather and wet weather flows are equally important. The former, to a large degree, determines the size and capacity of major plant units necessary to provide a given degree of treatment, while the latter determines the hydraulic capa- city of pipelines and plant units such as pumps, channels, and inlet and outlet structures. Future waste flows can be projected directly from information on population growth and per capita contribution of flow. Since the proposed project cons is ts of two wastewater pumping stations and a force main, development of peak wet weather flow (PWWF) is of principa 1 consideration. Many diverse methods are available for developing the projected flow rates. Development of flow rates is based on a historica 1 evaluation of a 11 compo- nents of flow including domestic, commer- cial and industrial wastewater flows, as well as infiltration and storm water inflow. Criteria are developed for average dry weather flow (ADWF), peak dry weather flow (PDWF) , and wet weather flows. The sum of the PDWF and wet weather flow represent the PWWF. As indicated by the present opera- ting records of the agencies in Table 4-5, Vista Sanitation District discharges about 2. 5 mgd or about 36 percent of the waste- water to the Encina WPCF and about 55-60 percent from the study area of this report. A small, but undetermined percentage of wastewater generated from Carlsbad occurs outside of the Agua Hedionda drainage basin. All present flows from Vista Sani- tation District are tributary to the Buena Vista pumping station, while the tota 1 flow within the study area from Vista Sanitation District and Carlsbad is tributary to the Agua Hedionda pumping station. 40 Existing and Projected Water and Wastewater Characteristics Dry Weather Flow, Dry weather wastewater flows generated within the study area include domestic, commercial, and industrial wastewater. For the most part, sewers within the study area are constructed above the groundwater table and infiltration during dry weather periods has been assumed to be negligible. Unit design loadings representing the average contributions of wastewater flow from residential areas within the study area were developed from a review of operating records, as well as from reported trends in unit domestic water con- sumption and wastewater flow. Wastewater flows are influenced by such factors as availability and relative cost of water, standard of living, and the general affluence of the economy. Unit loadings in recent years have risen because of the known trend toward increased household uses of water. For example, labor saving appliances such as garbage grinders, automatic home clothes washers and dishwashers require considerably greater volumes of water than did former equipment or methods 1• While published literature contains information relative to rates of water use when these appliances are in operation and on the volume used per operation, little recent data are available to indicate the frequency of use or the resulting increase in total unit water use. However, information based on studies prior to 1959 2 indicated total water use for garbage grinders, automatic home clothes washers and dishwashers ranging from 15 .5 to 19 gallons per capita per day (gcd). These values are partially offset by the water volume which would otherwise be used for clothes and dish washing. They do serve, however, to illustrate the magnitude of the effect of modern appliances on total water use. Characteristic of modern residential construction, it will be assumed that homes in the study area feature the labor saving appliances mentioned above. On this bas is, it is estimated that an average per capita domestic wastewater contribution of 9 0 gallons per day is appropriate for design purposes. Based upon an analysis of various California communities, an average contribution of 2,500 gallons per acre per day (gad) is considered representative of flow from commercial areas. Although the waste contribution from an individual industrial source is dependent upon the nature of the operation involved and will vary considerably, the above flow allowance is also considered applicable to "dry" industries. It is anticipated that in the future this type of industrial activity will predominate in the study area. Although knowledge of projected average dry weather flow (ADWF) is important in the sizing and_ planning of treatment plant units, it is also necessary to establish values for the peak rate of dry weather flow (PDWF). PDWF is always higher than ADWF by a ratio which varies with the contributory population. Typically, the ratio is large for small contributory areas and decreases as connected population increases. Fig. 4-1 shows the relationship between con- tributory population and the estimated ratio of peak to average dry weather domestic wastewater flow. Past and existing ratios for PDWF from Vista were determined from operating records at the Vista metering station and found to con- form to the curve. Since the flow is predominately domestic, the peak ratios are applied to commercial and industrial flows, as well as domestic. 2.6 2.S !It 2.4 () ... ... 2., ~22 It: ~ 2.1 .. e z.o le UI ~ 11. I.II ~ 1.1' .. It: 1.6 ~ /.4 I \ ' ' \ ' ' 2 I \, .. ' I I i I ! improvement and Eniargement of lne Buena Vista and Agua Hedionda Pumping Stations 41 ,_ I I 11 I ii i •I ,, ' II '-.!. ,: :"""-~ ~~ i ii . -----,_ ·-· -- I I I I I i I l ! ii Wet Weather Flow. Storm water inflow, the combined effect of wet weather infiltration and direct storm inflow, must be added to the PDWF to establish the PWWF. This parameter determines the maximum hydraulic capacity of pipelines, pumping stations and various treatment plant units. 10 20 /00 200 !SOO JOO() P0l'IJLATI0N, TH0IISAN0S In the study area, the increase in wet weather flow over dry weather flow is readily observed by referring to past records. During the month of February, 19 69 , severe local flooding took place Fig. 4-1. Ratio of Peak to Average Dry Weather Flow in the vicinity of the Buena Vista pumping station. Encina WPCF operating personnel report that all areas near the intersection of El Camino Real and Highway 78, near the May Company Shopping Center, were flooded on February 2, 1969. Due to the overloaded conditions of the transmission facilities and limited capacity of the pumping station, a temporary overflow of wastewater occurred as flow backed up in the Vista outfall. Capacity for storm- water inflow and infiltration must be provided in sewerage facilities to comply with Federal and State requirements which prohibit the discharge of wastewaters to areas other than formally approved disposal sites. Furthermore, emergency stand- by pumping capacity must be provided for to insure continuous operation during periods of electrical failures. The existing pumping stations presently do not have sufficient standby capacity and must be improved. 4.0 () .. -i &O AVERAGE DAILY FLOW M. G. 0.-7 it 2.0 Fig. 4-2. Hourly Flow Variation at Vista Metering Station During Typical Dry Weather Week -1969 42 Existing and Projected Water and Wastewater Characteristics The magnitude of infiltration into the sewerage system was estimated from the daily variation in rate of wastewater flow recorded at the Vista metering station. The daily minimum rates of flow in a period prior to wet weather as shown on Fig. 4-1 are consistently the same value up to actual rainfall. A comparison of the minimum rates of flow during dry weather with the largest minimum rate of flow following precipitation, shown on Fig. 4-3, indicates a difference of O. 8 mgd. Assuming negligible infiltration during the dry weather period, this differ- ence which may be attributed to infiltration amounts to about 190 gad for the tributary area. For purposes of this study, the rate of infiltration will be assumed to be 250 gad. This relatively low rate indicates that the extreme flows during wet weather are almost entirely due to storm inflow and that infiltration is a minor consideration in the present system. The hourly rates of flow at the Vista metering station during the wet weather week of January 23 through 29, 1969, have been shown on Fig. 4-3. The rate of storm inflow on a rainy day is represented by the difference between the rate at a given time on that day and the rate on comparable dry days. For example, a peak rate of 5.0 mgd was recorded at 1:00 P.M. on January 25, while the rate averaged 2 .1 mgd at the same time during the period January 2 through 9 when there had been no rainfall. The excess is for the most part attributable to storm inflow. With approximately 4,200 acres tributary to the metering station, the rate of inflow in this case is equivalent to 690 gad. A stormwater inflow rate of 750 gad will be utilized in the study. 6.0 .-------.-------.------r-------.--------r----....-----, 5.0 1-------+-----+---r---+------+------+----+------i AVERAGE DAILY FLOW MG.~ 4Dl-------+-----+----l~-+------+------+-----'--+------! rNURS.-JANIS FRI.-JAN.H SAr-JAN.15 SUN.-.IAN.16 --✓AN.17 WEJJ.-JAN..ttl Fig. 4-3. Effect of Heavy Rainfall on Hourly Flow Variations at Vista Metering Station -1969 Improvement and Enlargement of che Buena Vista and Agua Hedionda Pumping Stations 43 While the method of determining stormwater inflow and infiltration is approximate, it is indicative of the storm flow contributions to the systems in the study area. Wastewater systems may be expected to have an economic life of 50-100 years or more. During this period it can be anticipated that the water tightness of sewers will progressively deteriorate from the combined effects of settlement, root penetration, faulty service connections, and the 1 ike. However, because most modern sewers are water tight when constructed, it is reasonable to assume that deterioration will be gradual. For these reasons a value of 1,000 gad for infiltration and direct storm inflow is generally considered an appropriate bas is for computing peak flows. Table 4-6. Summary of Unit Design Criteria Item Wastewater volume Domestic Average flow, gcd Peak flow Commercial Average flow, gad Peak flow, gad Storm water inflow, gad Infiltration Direct storm inflow gcd = gallons per capita per day gad = gallons per acre per day Factor 90 a 2, 500 a 1,000 250 750 a Dependent upon magnitude of contributory population. Design Quantities A summary of the unit design factors previously discussed is given in Table 4-6. By applying these factors to the forecasts of future land use and population, quantities were projected for wastewater volume at various phases of development of the study area. It was assumed that sewerage service would be provided to a 11 of the developed areas. Table 4-7 and Table 4-8 present the projected flows to each of the pumpina stations considered herein, while Fig. 4-4 presents both the PWWF and ADWF projections. Although design of pumping stations is based on PWWF, the ADWF have been included so that a determination may readily be made of the equivalent PWWF. It should be recognized, however, that the projected flows may occur at a faster or slower rate than anticipated due to many factors which are difficult to predict. Factors which may affect the PWWF projections include rate of urban development, rate of domes tic use of water, number and type of ind us tria 1 develop men ts, quality of future pipeline construction and the effectiveness of future programs prohibit- ing illicit drainage connections to the sewerage system. 44 Existing and Projected Water and Wastewater Characteristics Table 4-7. Projected Wastewater Flows -Bueno Vista Pumping Station De script ion 1970 1980 1990 2000 2010 Average dry weather Domestic 1.91 4. 12 6.05 7.66 8.90 Commercial and industrial 0.53 0.84 1. 22 1. 56 1. 80 Total ADWF 2.44 4.96 7.27 9.22 10. 70 Peak dry weather Domestic 3. 32 ---- Commercial and industrial 1. 59 ---- Total PDWFa 4.05 7. 7 5 11. 05 13. 91 16.05 Peak wet weather PDWF 4.05 7.75 11. 05 13. 91 16.05 Inflow and infiltration 2.35 3. 77 5.46 7.01 8.04 Total PWWF 6.40 11. 52 16. 51 20.92 24.09 aPDWF computed by applying peaking factor to total ADWF alone. Table 4-8. Projected Wastewater Flows -Agua Hedionda Pumping Station De script ion 1970 1980 1990 2000 2010 Average dry weather Domestic 2.57 6,40 9.57 13.02 16.59 Commercial and industrial o. 64 1. 03 1.53 2.01 2.41 Total ADWF 3.21 7,43 11, 10 15.03 19.00 Peak dry weather Domestic 4.38 ---- Commercial and industrial 1. 92 ---- Total PDWFa 5.20 11.37 16.65 22.60 28.50 Peak wet weather PDWF 5.20 11.37 16.65 22.60 28.50 Inflow and infiltration 2. 93 4.80 7,26 9.80 12.23 Total PWWF 8. 13 16.17 23.91 32.40 40.73 a PDWF computed by applying peaking factor to total ADWF alone. Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations 40.0~----~----~-----~---~ Fig. 4-4. Projected Wastewater Flows 45 46 CHAPTER 5 ANALYSIS OF EXISTING WASTEWATER MANAGEMENT SYSTEM The Buena Vista and Agua Hedionda wastewater pumping stations are part of the Encina Joint Sewerage Agency system which consists of facilities to consoli- date wastewater from individual communities at the Encina WPCF for treatment and disposal. There are currently six agencies within the regional service area responsible for providing sewerage service: Vista Sanitation District, the City of Carlsbad, Buena Sanitation District, San Marcos County Water District, Leucadia County Water District, and Encinitas Sanitary District. Boundaries of the agencies, treatment plant location, major outfall and interceptor sewers, and pumping stations are shown on Fig. 5-1. The facilities under consideration in this study are limited to those which serve Vista Sanitation District and the City of Carlsbad. INSTITUTIONAL ARRANGEMENTS The alternatives proposed later in this report concern Vista Sanitation Dis- trict and the City of Carlsbad relative to the Encina Joint Powers Agreement which defines the institutional arrangements among the participants in the regional sewerage agency. Each of these entities is discussed below. Vista Sanitation District The Vista Sanitation District was formed on February 24, 1947, under the County Sanitation District Act of California and is presently serving an area of about 5,000 acres. The City of Vista is located in the eastern end of the Buena Vista drainage area at a distance of approximately 7 miles from the ocean and has a population of about 25,000. Elevations within the District range from 300 to 1,000 feet above sea level. Vista was incorporated as a city in January, 1963, after which the City Council of Vista became the governing board of the Vista Sanitation District. Prior to connecting to the Encina WPCF in September, 19 65, treatment facilities for Vista included a O. 2 0 mgd trickling filter plant and a second treatment facility with a capacity of O. 70 mgd which employed oxidation ponds. The plant effluent was discharged into Buena Vista Creek and while some of the effluent was withdrawn from the creek to irrigate the El Camino County Club Golf Course, the majority flowed approximately 4 miles to Buena Vista Lagoon. City of Carlsbad In July, 1952, the City of Carlsbad was incorporated as a general law city of the sixth class with an area totally encompassing the existing Carlsbad .,. .,_ 2000 •L ~AGUA PU,MPING SCALE IN FEET 2000 4000 ' •f "' . .,, OCEANSIDE ,, . ., 0000 ., BUEN A ... ... . . . \" I /' I \ ' I \ I< VISTA SANITATION DISTRICT ' ' ' BUENA SANJT,A.TION DISTRICT r 14iJFM-L2 ....... ' "' • ,- I I I I I .. .• LEGEND STUDY AREA BOUNDARY SERVICE AGENCY BOUNDARY DRA,INAGE BASIN BOUNDARY EXISTING GRAVITY SEWER ( SIZE , CAPACITY--MGD) EXISTING FORCE MAIN (S'ZE ,'CAPACITY-MGD) ~~ ·I • Fig. 5-1. Exis t j, )· .. --:- "f' Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations 47 Sanitary District. Subsequently, the City assumed the responsibility for the wastewater treatment works and collection system, and the superceded Sanitary District was dissolved in June, 1953. Presently, Carlsbad has a population of about 18,000 and a service area of about 4,800 acres. Carlsbad is a coastal community and its landward boundary rises to an elevation of some 300 feet above sea level. Under the ownership of the City of Carlsbad, the sewerage works, comprising a septic tank, effluent pumping station and ocean outfall continued until 19 55. At that time a secondary treatment plant was constructed and placed into operation in July, 1956. Wastewater effluent was discharged to the ocean and Buena Vista Lagoon. As a result of effluent discharges from the communities of Vista and Carlsbad, Buena Vista Lagoon became seriously polluted and was a source of nuisances such as obnoxious odors and heavy algae growths. A "cease and desist" order was issued by the San Diego Water Pollution Control Board to stop the discharge of these waters into the Lagoon. It was then that the need for regional planning was realized. The existing plant is now the site of a pumping station which trans- ports wastes into the Carlsbad interceptor sewer. Carlsbad connected to the Encina WPCF in September, 19 65. Basic Joint Powers Agreement Vista Sanitation District, the City of Carlsbad, Buena Sanitation District, San Marcos County Water District, Leucadia County Water District and Encinitas Sanitary District are presently joined together as described in the Basic Joint Powers Agreement and subsequent supplements to form the Joint Advisory Committee (JAC) for the purposes of advising on the operation and administration of jointly owned wastewater transmission, treatment and disposal facilities. The first formal action taken by the governing bodies to implement engineer- ing findings was the execution of a Basic Agreement, pursuant to the State of California Government Code, between the City of Carlsbad and the Vista Sanitation District. Signed in July, 19 61, the Joint Powers Agreement provided for the acquisition, construction, ownership, maintenance, operation and use of a system of major sewers, pumping stations, force mains, metering stations, treatment works and ocean outfall. The Agreement also established sewer service areas, capacity rights in each portion of the joint system and an overall method of cost sharing. Recognizing the benefits of a system defined by drainage 1 im its, the following two restrictions were placed on the service between drainage basins and service areas: ( 1) pumping of wastewater from one basin to another is limited to 50 acres or 50,000 gpd; (2) permanent pumping of wastewater from one basin to another is not permitted. In addition, each agency was given sole control over their service area. As evidence of the intention to "regional ize" the area, a statement was included which indicated the intent of Vista and Carlsbad to perm it the plant and outfall to be enlarged to serve other agencies, such as Leucadia and Encinitas. 48 Analysis of Existing Wastewater Management System In January, 19 64, the Buena Sanitation District became the third cooperating agency by agreeing in the "Second Supplement" to participate in the cost of owner- ship and operation of the treatment plant and ocean outfall portion of the system. The "Third Supplement", signed in March, 1965, allowed San Marcos to become a party to the basic agreement, and became effective in June, 19 68. The two agencies on the southern boundary of the regional service area, Leucadia County Water District and Encinitas Sanitary District, have formally agreed with the four owners to become participants in the jointly owned Encina Water Pollution Control Facility and Ocean Outfall. In May, 1974, the 6th Supplement to the Basic Agreement was signed which defines the conditions for the participation of Leucadia and Encinitas. A significant portion of the City of Oceanside is within the Buena Vista Drainage Bas in. It would be feasible, both from an engineering standpoint and on the bas is of economics, for Oceanside to join the Enc in a Joint Powers and have wastewater flows from this area transported to the Encina WPCF. However, Oceanside decided several years ago to construct their own treatment facilities and pump the wastewater out of the Buena Vista drainage basin to the north for treatment and disposal. In August, 19 65, an agreement for operation of the joint system by the County Department of Sanitation and Flood Control was made on behalf of the owners. The initial operation of the 4. 5 mgd capacity system began in September, 19 65. WASTEWATER FACILITIES The following paragraphs present a description of the wastewater facilities investigated during the preparation of this report. Interceptor Sewers The interceptor sewer system serving Vista and Carlsbad commences at the abandoned Vista wastewater treatment plant and generally follows Buena Vista Creek and State Highway 78. Wastewater from the Vista service area is metered at the Carlsbad city limits by the Vista metering station. The Vista outfall sewer continues westerly to the Buena Vista pumping station located at the head of the Buena Vista Lagoon. Wastewater collected at the pumping station must be lifted through a 16-inch force main located in Jefferson Street. After crossing Interstate 5, the flow continues by gravity through the City of Carlsbad to the Agua Hedionda pumping station. Wastewater from the Carlsbad and Vista service areas is again lifted through a short force ma in to the coastal interceptor, east of and parallel to the Santa Fe railroad tracks. The 42-inch coastal interceptor conveys these wastewaters to the headworks of the Encina WPCF. Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations Vista Metering Station 49 The Vista metering station is located approximately 14,000 feet to the east of the Buena Vista pumping station on the 27-inch diameter section of the gravity interceptor sewer as shown in Fig. 5-1. The equipment located in the metering station includes a 27-inch diameter Palmer-Bowlus metering flume and an indica- ting, recording, and totalizing, float-actuated flowmeter, with a capacity of 10 mgd. A by-pass channel is also installed along with a backflow preventer, and a sump pump. An air blower and injector is incorporated to minimize effects of hydrogen sulfide (H2S) action on pipe crown corrosion. This metering station is utilized for measuring all of the raw wastewater flow from the Vista Sanitation District. The flow data from this station provides the only means of establishing the District's share of the operation and maintenance cost of the joint sewerage system. Pumping Stations The pumping stations incorporate, wherever applicable, such modern design features as: variable speed devices, standby power, air injection, adequate ventilation, hoisting mechanisms and adequate work space. Buena Vista Pumping Station. The Buena Vista Pumping Station, located on Jefferson Street at the head of Buena Vista Lagoon, con ta ins three wastewater pumps. Two pumps are variable speed, each with a capacity of 2,400 gpm (3. 46 mgd) at 90 feet of head. The third pump is a constant speed type, with a capacity of 2,550 gpm (3. 67 mgd) at 84 feet of head. All three pumps are powered by 7 5 Hp electric motors and the constant speed pump is connected to a standby engine fueled with LPG, which is designed to provide standby pumping capability in case of a power failure. The capacity of the pumping station with the two smaller pumps in operation and the larger unit serving as standby is rated at 3200 gpm (4. 61 mgd). Since the pump interlock has been removed, however, a flow rate of 4,000 gpm (5. 76 mgd) could be achieved with all three pumps in operation. A 1,900 pound LPG storage tank is located adjacent to the pumping station. A bubbler tube type liquid level sensor is utilized for determination of the water level in the wet well and consequent sequential pump motor operations. To reduce hydrogen sulfide problems inherent to stale or septic wastewater, a rotary air compressor supplies air at variable pressures for injection into the force main. The pumping station itself is a circular design, as shown in Fig. 5-2, with a diameter of approximately 42 feet. The station has two levels with the motor and control room located at ground level and the pump room (dry well) and wet well located 20 feet below. Access to the wet well is by a central stairway and grating, while access to the pumps is by a circular stairway located along the inside of the exterior wall. The wet well is located in the center of the building and has a 30-inch wastewater inlet through a manually cleaned trash rack. A slide gate is provided on the sewer inlet and is manually operated from the upper level. The wet well is 8 feet by 15 feet by 7. 5 feet with an approximate capacity of 674 cubic feet or 5,040 gallons at the high water alarm level of 6 feet. There is also additional storage volume in the inlet channel and gravity sewer. 50 Analysis of Existing Wastewater Management System The mechanical equipment configuration within the pumping station consists of vertical shaft pumps mounted on the lower level with the corresponding motors and controls located on the upper floor. A drainage system is provided in the dry well with a sump pump discharging directly into the wet well. A toilet is provided on the upper level which drains directly into the wet well, as does the roof drain pipe. The air compressor for hydrogen sulfide (H2S) suppression is located on the lower level, adjacent to the inlet sewer. The wastewater pumps are vertical non-clog centrifugal type and are arranged with gate valves on both the suction and discharge sides. Furthermore, a swing check valve is located vertically, on the discharge side to prevent backflow through the pump. The 10-inch and 12-inch discharge pipes join in a common 16- inch wye header at the entrance to the force main. At maximum flow rates, there is almost 6 feet of head loss associated with the suction and discharge piping. There are two positions available for mounting additional pumps within the existing pumping station. The sequencing operation on the pumps is based upon both total pump capa- cities and corresponding 1 iquid levels in the wet well. Furthermore, an alternator has been provided to alternate the sequencing of the variable speed pumps, thereby insuring their standby availability at all times, evenly distributing motor and drive mechanism wear, and prolonging component life. The standby engine on the constant speed pump can either be started automatically or can be started manually, depending upon the appropriate selector switch positioning 1• An automatic 3-step sequencer is also installeq and used to "exercise" the constant speed pump. This sequence starts the constant speed pump every third starting cycle, on a pre-set high level signal, and the pump runs until a pre-set low level is indicated. A sophisticated and comprehensive alarm system covers the entire pumping station operation. High water levels in either the wet well or in the dry well will cause alarm lights and bells to be activated. Alarms are also included for com- pressor failure and heater overload at the pump motor starters. There is a silencer button to shut off the alarm bell but the light remains on until the alarm condition is corrected. Local alarms are also provided for over-cranking of the engine of the constant speed pump, low lubrication oil level, high cooling water temperature, low cooling water level and engine overspeed conditions .• Agua Hedionda Pumping Station. The Agua Hedionda Pumping Station is located on the side of a small hill, just south of Agua Hedionda Lagoon and east of the Santa Fe railroad tracks. The station is of a rectangular type construction, as shown in Fig. 5-3, 41 feet by 21. 5 feet by 24. 5 feet with about 10 feet exposed above ground. The raw wastewater enters at the north end by means of a 42-inch diameter reinforced concrete pipe which is 1 ined with polyvinylchloride (PVC), and passes through an externally operated slide gate and a manually cleaned trash rack. The wet well is 22.5 feet by 6 feet by 7 feet with a capacity of 765 cubic feet or 5,725 gallons at the high water level of 6. 2 feet. There is additional storage capacity in the inlet structure and influent sewer. Access to the influent sewer is provided by a manhole located about 30 feet north of the pumping station. An overflow culvert is located in the manhole which would divert wastewater into the southern portion of Agua Hedionda Lagoon during periods of high flow when the existing pumping capacity is exceeded. Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations There are three non-clog wastewater pumps of the vertical, centrifugal 51 type located in 1 ine, adjacent to the wet well. The first two pumps are direct- coupled to variable speed, 40 Hp motors, and are each capable of discharging 3,850 (5.55 mgd) gallons per minute at 1150 rpm against 26 feet of head. When both pumps operate in parallel the capacity is 7 350 gpm ( 10. 6 mgd) at 1150 rpm against 28 feet of head. The third pump is a constant speed, non-clog, vertical, centrifugal type wastewater pump which is currently fitted with a vertical shaft and a remotely driven 40 Hp motor mounted on the first level of the pumping station. Similar to Buena Vista Pumping Station, recent removal of a pump inter- lock will allow the three pumps to operate simultaneously, if necessary, to achieve a capacity of 10,850 gpm (14,9 mgd). The outout of the third pump was originally 3050 gpm (4. 4 mgd) at 1150 rpm against 24 feet of head, but a change in impeller size has enabled the pump to discharge 3850 gpm (5. 55 mgd) at 1150 rpm against 26 feet of head, with no increase in the existing motor size. The constant speed pump is also connected to a standby LPG fueled engine through a right angle gear drive. This engine is designed to provide standby pumping capability in case of a power failure. A 280 cubic foot, 100 psig, LPG storage tank is located adjacent to the pumping station. The wastewater pumps are installed with gate valves on both the suction and discharge sides, and have swing check valves on the discharge side to prevent wastewater back-flow. The 12-inch discharge pipes of the pumps join in a common 18-inch wye header at the entrance to the force main. At maximum flow rates there is almost 7 feet of head loss associated with the suction and discharge piping. There is one position available in the pumping station for mounting an additional variable speed pump of the same configuration as the existing pumps 2 . Deficiencies in Present Operations. There are several problems associated with the layout and operation of the existing facil iti.es. These are discussed in detail for each pumping station. Buena Vista Pumping Station Deficiencies. Potential for expansion of the Buena Vista Pumping Station is hampered by the small size of the existing force main, the length of the force main, and the static lift involved. As the peak pumping capacity is approached, the. dynamic losses in the force main first become quite high and then excessive as shown by system curves discussed in Chapter 8. The existing pumps cannot discharge against static and dynamic heads greater than 70 feet and 35-37 feet, respectively, at a flow rate of 4000 gpm (5. 7 6 mgd}. Since 5. 76 mgd is the maximum flow with all three existing pumps in operation, however, there is no back-up capability in case of equipment failure. In order to pump 8 mgd or 5200 gpm, the pumps must function against a head loss of 135 feet, while the head would be reduced to 105 feet at 8 mgd upon the addition of a parallel 16-inch force main. The three existing pumps , however, could not meet this demand. The addition of two similar pumps would not be warranted due to the high head requirements imposed by the relatively small exist- ing force main. The existing pumps are all undersized and should be phased out in favor of larger capacity pumps in conjunction with a parallel force main. 52 Analysis of Existing Wastewater Management System Difficulty in providing additional capacity is further compounded by deficien- cies in the wet well and pump suction inlets. The pump suction lines are piped directly into the wet well with no increase in pipe diameter, thereby causing the velocity at the suction pipe inlet for a given flow rate to be the same as the veloci- ty to the pump. The relatively high velocity at the inlet causes a vortex to be formed at each inlet in the wet well. Vortexing causes air to be sucked into the pump, further reducing the total pumping capacity. The problem of vortexing can be minimized by maintaining a water level five to ten feet above the level of the suction inlets or possibly by installing baffles. In the Buena Vista Pumping Station, low water level in the wet well is only 2. 5 feet above the suction inlets. Modifications and improvements to the existing pumping station are also needed to insure efficient operation during failures and other emergency conditions. As stated previously, standby power for pumping is currently inadequate, and will become increasingly deficient as wastewater flow rates increase. For example, if a loss of electrical power presently took place during a period of PWWF, internal flooding would occur. Furthermore, there is no isolation of the wet well from the remainder of the pumping station, thereby causing the entire pumping station to flood if the wet well becomes flooded. As long as the possibility of flooding exists, the wet well should be isolated to minimize the danger of damage to the fac i1 ity. Agua Hedionda Pumping Station Deficiencies. Agua Hedionda Pumping Station has inadequacies similar to Buena Vista pumping station relative to the capacity of the wet well, and standby power protection. The major problem with the existing facility is the relatively low capacity of the existing pumps. The low static lift and short force main with medium diameter, combine to produce a workable system curve which exhibits low dynamic head loss at moderate to high flows. The maximum capacity of the pumps is so low, however, that the PWWF at year 1985 could not be attained by adding similar pumps. Furthermore, velocities in the single force main become excessive at peak flow rates. At current rates of population growth, simply adding additional pumps to the pumping station would only provide capacity to the year 1985. Even with the addi- tion of a new impeller to the constant speed pump and installation of another 10 x 8 x 13 pump, the maximum flow would only be 16 mgd, or only a little more than half of the estimated PWWF at the year 2000. The problem of vortexing which exists in the wet well would continue to occur due to the small suction nozzles, thereby lowering the projected pump capacities. The motor control center is presently located on the lower level adjacent to the wet well, a location subject to potential flooding from a pump or line failure. Future construction should include either repositioning the motor control center or major building modifications. The pumping station is currently vulnerable to dry well flooding and shorting out of all the motors and control circuitry. Leaving the motor control panel in the dry well could prove dangerous, since a single pump, valve or piping failure could cause the station to cease pumping operations. Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations Encina Water Pollution Control Facility 53 The Encina WPCF provides primary treatment and was constructed with an ADWF capacity of 4.50 mgd. During Phase 1 enlargement in 1971, the ADWF design capacity was increased to 6. 75 mgd by adding a third primary sedimenta- tion tank. Phase II and IIA enlargements to the treatment plant which have recently been designed and are presently under construction, will increase the ADWF capacity to 13. 7 5 mgd by the end of 197 4. Rapid development in the ser- vice area of the joint power agencies prompted the latter expansion which adds a fifth sedimentation tank to the facility and 4. 0 mgd in capacity. Design data for the existing plant, including Phases II and IIA, are listed in Table 5-1. A sche- matic flow diagram of the treatment facility is shown in Fig. 5-4. Wastewater Table 5-1. Encino WPCF Design Data Present Phase 2 Present Phase 2 Item plant and 2Aa Item plant and 2Aa Design loadings Sludge treatment Population equivalent, Sludge digester thousands 63 128 Number 2 3 Flow, mgd Inside diameter, feet so so Average dry weather 6.75 13.75 Side water depth, feet Peak dry weather 11. 25 21.l Fixed cover (number) 23 23 (1) Peak wet weather 16.25 34.8 Floating cover (number) 18-24 18-24 (2) BOD5, 1,000 lbs/day 13.75 29.S Total volume per tank, Suspended solids, 1000 lbs/ 1000 cu.ft. 48.8 48. 8 day 17.0 33.7 Loading, lbs volatile Wastewater metering solids per cu.ft/day o. 16 0 .11 Palmer-Bowlus Flume Dewatering centrifuge Number 1 0 Number 1 1 Throat width, inches 12 -Bowl dimensions, inches 24x60 24x60 Maximum capacity, mgd 35 -Solids content in digested Cutthroat Flume sludge, percent 4' 4 Number 0 1 Digester sludge feed rate, Throat width, inches -12 gpm 75 75 Maximum capacity, mgd -30 Motor horsepower 75 75 Preliminary treatment Sludge drying beds Mechanical bar screens Number 20 20 Number 1 2 Dimensions Width, feet 3 3 Width, feet 35 35 Channel depth, feet s.s s.s Length, feet 60 60 Screenings grinder Total area, sq.ft. 42,000 42,000 Number 1 1 Grit treatment Capacity, cu. ft. /hr. 60 60 Grit washer Preaeration grit removal Number 1 1 tanks Capacity, gpm 300 300 Number 1 1 Surface area, sq. ft. 21 21 Width x length x water Surface settling rate, depth; 20x30xl5 20x30xl5 gallons/sq. ft/min. 14 14 Detention time, min. 15.8 7.8 Chlorine treatment Primary treatment Chlorinators Sedimentation tanks Number 2 2 Number 3 5 Capacity, lbs/day /unit 1,000 1,000 Width, length, water depth, each, ft. 20xl60x9 20xl60x9 Effluent weir length per a Currently under construction. tank, feet 160 160 b When operating 3 primary digesters at ADWF and Design flow per tank, mgd 2.25 2.76 assuming 60 percent removal in the primary Detention time, hours 2.3 1.9 sedimentation tank and 70 percent volatile solids. Surface overflow rate at ADWF gal/sq. ft/day 700 860 54 Analysis of Existing Wastewater Management System conveyed to the plant enters by gravity and passes through a bar screen, an aerated grit removal unit and primary sedimentation tanks. Effluent may be chlorinated prior to discharge to the ocean outfall, while chlorination facilities are also provided for odor control at two points prior to primary sedimentation. A small portion of the effluent is used for irrigation of the grounds, to prevent an excessive buildup of foam in the aerated grit removal tank and channels, and to flush solids through the screenings grinder. In order to meet recently adopted waste discharge re- quirements discussed in Chapter 6, the existing WPCF will be upgraded by providing secondary treatment. The SWRCB has placed the project on the FY 197 4-7 5 priority list for the receipt of Federal and State grants. I I I I RAW SEWAGE FLOW METER CHLORINE BAR SCREEN GRINDER AIR AERATED GRIT REMOVAL GRIT WASHER GRIT BURIAL SLUDGE DRYING BED DRAINAGE NORMAL OPERATION ALTERNATIVE OPERATION CHLORINE INFLUENT SAMPLE PRIMARY SEDIMENTATION RAW SLUDGE SCUM CHLORINE EFFLUENT TO OCEAN EFFLUENT SAMPLE RAW SLUDGE PUMPS STEAM ,__..._INJECTION SLUDGE DRYING BEDS CENTRATE CENTRIFUGE DIGESTED SLUDGE SOLIDS DISPOSAL FERTILIZER Fig. 5-4. Schematic Flow Diagram -Encino WPCF Grit removed from the wastewater is comprised of heavier particulate matter, principally sand, gravel, egg shells, coffee grounds and some organic matter. Because the grit contains a small amount of putrescible matter it is disposed of by on-and off-site burial for control of odor and fly nuisance. Putrescible solid residues from the primary sedimentation process are stabilized by anaerobic digestion. The existing digestion system consists of two SO-foot diameter primary digesters with fixed concrete roofs, while an identically sized digester with floating steel cover is being provided during Phase II. For higher efficiency, the digesters are heated to temperatures of 90-9S°F by injecting steam into the sludge and are mixed by gas circulation. The digested sludge is dewatered by centrifugation and the centrate is transferred to drying beds which are provided with graded sand and aggregate material. After dewatering, the sludge and dried centrate is pulverized for use as a soil conditioner. At present,disposal of the dried digested sludge has not been a problem, since the demand for the dried sludge has been greater than its supply. 0 z 0 1--u w (/) ....J w > w ....J 0::: w 3: 0 ....J I 3: w > z <{ ....J 0.. r---------- 1 I I I I I I I I I I I I I I I I I I I ft _'¥ __ _ ---<- I I I I I I ----=--=-===- C 0 :;: 2 II) Cl .!: CL E :::, 11. 2 Ill > 0 C GI :::, CCI -0 C .!:! 11. Cl .!: .. • !!! >< w c--i ,J, -~ IL ....J w > w ....J PUMP (OPEN) PUMP NO. PLAN VIEW -LOWER LEVEL r--------------------------- 1 :®• I I L----------~lt=~~~=======~~~~~~~~ PLAN VIEW -UPPER LEVEL NO. 3 NO. 2 SECTION 0 SECTION 0 Fig. 5-3. Existing Plan of Agua Hedionda Pumping Station Effluent Outfall Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations 55 The land portion of the effluent outfall system consists of about l, 100 feet of 48-inch diameter reinforced concrete pipe. The pipeline commences at the WPCF effluent sampling station and joins the ocean portion of the outfall at the west edge of old Highway 101, now S2 l. The original ocean portion of the dis- posal system consists of 5,500 feet of 48-inch diameter reinforced concrete pipe. During the Phase II construction program, the ocean outfall was extended from a depth of approximately 100 feet to 170 feet. The original outfall was extended by laying approximately 2,300 feet of 72-inch pipe terminating in a 700 foot multiport diffuser. Although the outfall design was based on the discharge of unchlorinated effluent, post chlorination facilities are available at the treatment plant for use during periods of continuous onshore currents, unexpected peak wastewater flows or to meet emergency conditions. 56 CHAPTER 6 WASTE DISCHARGE AND TREATMENT REQUIREMENTS Waters that are adversely affected by wastewaters in the study area, quality requirements and goals for the wastewater and waters affected, and the need for action to assure that those requirements and goals will be met, are dis- cussed below. Water Quality Requirements and Goals Presented in Appendix Bis Order No. 74-21 of the California Regional Water Quality Control Board, San Diego Region, (RWQCB) which specifies waste dis- charge requirements for the wastewater discharge to the ocean waters offshore of Canyon de Las Encinas. The above document describes the beneficial uses of receiving waters that might be affected by wastewater discharge and stipulates water quality conditions not to be caused and water quality criteria not to be violated by the discharge. Quality requirements are stipulated for receiving waters and for the wastewater. These requirements were promulgated subsequent to both the adoption of the State Water Quality Control Plan for Ocean Waters of California (Ocean Plan)l and to recent Federal legislation, thereby incorporating both of the most recent effluent quality requirements. Furthermore, it is now standard governmental policy to prohibit bypassing of wet weather wastewater flows to local receiving waters. The waste discharge requirements adopted by the RWQCB as Order No. 74-21 also serve as the NPDES permit which is required for all municipal dischargers pursuant to the Federal Water Pollution Control Act. Effluent discharge requirements of the Ocean Plan are shown in Table 6-1. The discharge must also meet several receiving water quality objectives which define acceptable levels of bacteriological, physical, chemical, biological, toxicity, and radioactivity characteristics. A provision of the Ocean Plan allows a request for less restrictive effluent quality requirements if analyses demonstrate that the water quality objectives can be achieved with effluent quality character- istics other than those required by the Ocean Plan. Ferleral legislation embodied in an act termed the "Federal Water Pollution Control Act Amendments of 19 72" passed by Congress on October 4, 1972, and approved over presidential veto on October 18, 1972, however, requires all wastewater dischargers to provide a minimum of secondary treatment. Secondary treatment has been defined in part as providing a minimum of 85 percent BOD 5 removal or maintaining an average monthly BOD5 and suspended solids concentration of 30 mg/1, whichever is more restrictive. Provis ion of secondary treatment would generally meet all requirements of the Ocean Plan. Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations Tobie 6-1. Effluent Quality Requirements of Ocean Plon° Concentration not to be exceeded more than: Unit of Effluent constituent measurement 50% of time 10% of time Grease and oil (hexane extractables) mg/1 10.0d 15.0d Floating particulates (dry weight) mg/I 1.od 2 .ad Suspended solids mg/1 50 .od 75 .od Settleable solids ml/I 0. 1d 0.2d Turbidity JTU so.ad 75 .od Arsenic mg/I 0.01 0.02 Cadmium mg/1 0.02 0.03 Total chromium mg/I o.oos 0.01 Copper mg/I 0.2 ~.3 Lead mg/I 0.1 0.2 Mercury mg/I 0.001 0.002 Nickel mg/1 0.1 0.2 Silver mg/1 0.02 0.04 Zinc mg/1 0.3 o.s Cyanide mg/I 0.1 0.2 Phenolic compounds mg/I o.s 1.0 Total chlorine residual mg/I 1.0 2.0 Ammonia (expressed as nitrogen) mg/I 40.0 60.0 Total identifiable chlorinated hydrocarbonsb mg/1 0.002 0.004 Toxicity concentratlonc tu 1.5 2.0 pH units within limits of 6. 0 to 9. 0 at all time,;. Radioactivity -not to exceed the limits specified in the California Administrative Code. a Source: Water Quality Control Plan for Ocean Waters of California, SWRCB, July 1972 b Includes DDT, DDD, DDE, Aldrin, BHC, chlordane, endrin, heptachlor, lindane, dieldrin, polychlorin- ated biphenyls, and other identifiable chlorinated hydrocarbons. c Equals 10~ 96-hr.Lm,% d The State Ocean Water Quality Plan allows less restrictive effluent quality requirements if it can be demonstrated that the water quality objectives can be achieved with effluent quality characteristics other than those required by the Ocean Plan. Waters Affected by Wastewater Discharge 57 Agua Hedionda Lagoon is presently being utilized for water contact re- creation and it is the intention of the RWQCB to also attain such quality for Buena Vista Lagoon. Present water quality requirements for coastal lagoons prohibit any discharges which would raise the natural nutrient levels and thereby promote algal blooms and accelerate growths of other aquatic plants. No portion of any wastewater flow is currently being discharged to any natural watercourse within the study area under normal conditions. However, a pump failure, in combination with high flow conditions can result in spillage into either of the lagoons which adjoin the pumping stations. Existing drainage 58 Waste Discharge and Treatment Requirements conduits from either the Buena Vista or Agua Hedionda pumping stations will dis- charge excess wastewater during flood conditions into the neighboring lagoons. Buena Vista Creek and Lagoon. The eastern portion of Buena Vista lagoon is used extensively by waterfowl as a feeding area, and is currently classified as a wildlife bird refuge. The shallow water levels, caused by sedimentation, create natural levees and marshes which breed insects, lizards and small fish on which birds may feed. Excessive nutrient inflow to this area could easily upset the delicate natural balance which is currently in effect. Since there are so few natural havens for birds and wildlife along the California coast, the loss of another refuge could have quite a significant effect upon the bird population in Southern California. Buena Vista Creek flows by the south side of the Buena Vista Pumping Sta- tion, under the Jefferson Street Bridge and into the head of Buena Vista Lagoon. There is an earthwork bunker surrounding the pumping station on all four sides to protect the station from exterior flooding, such as occurred in 1969. However, drainage from the pumping station area is directed through a 12-inch corrugated steel culvert into the creek and the lagoon. Interior flooding of the pumping station would cause wastewater overflows to the parking lot with subsequent drainage through the culvert into the lagoon. Agua Hedionda Lagoon. The Agua Hedionda Pumping Station is located on a small rise on the south side of the ocean inlet to Agua Hedionda Lagoon. On the north side of the inlet is a YMCA day camp which utilizes the lagoon for boating and swimming. Private boat moorings are located along the north shore of the lagoon and water skiing is a popular recreational activity during the warmer months. Due to the low bridges across the inlet mouth, however, no ocean going sailboats are currently docked in the lagoon. Most recreational activities take place in the western end of the lagoon where the water is considerably deeper, while the eastern end of the lagoon supports insects and wildlife and is a resting place for migrating waterfowl. Need for Action Population projections, inflow and infiltration rates and present flow varia- tions indicate that the PWWF in the Buena Vista basin will reach 20 mgd between the years 1995 and 2000. If the Buena Vista pumping station cannot handle this flow, it will overflow manholes, eventually draining into Buena Vista Lagoon. Although capacity for the year 2000 is not required immediately, initial construct- ion phases should be designed to adequately convey PWWF projected for the per- iod under consideration. Projections indicate the need for a capacity of about 14. O mgd by 1985, greatly exceeding the present capacity of 4. 6 mgd. Besides the need to protect the adjacent lagoon from wastewater overflows, it is necessary to make minor modifications to the existing Buena Vista Pumping Station to prevent physical damage to the station. Flooding due to excessive wastewater flows could occur inside the station, since the wet well is not sufficiently isolated from the dry well and motor control center. Flooding of the Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations 59 pumping station could result in the loss of over$ 100,000 worth of mechanical and electrical equipment inside the building. Associated with the need to main- tain sufficient flow capacity at all times, provision of an adequate standby power source is also a necessity. Existing standby power for the Buena Vista Pumping Station is inadequate to handle current peak flow requirements, and would not provide additional power for lighting, ventilation and motor control circuits. The Agua Hedionda Pumping Station also faces similar but less immediate problems of inadequate pumping capacity and standby power. Furthermore, the existing overflow pipe will prevent the station from flooding out in the event of a power failure. Wastewater overflows, however, would be discharged directly to Agua Hedionda Lagoon and could create serious aesthetic and public health problems. 60 CHAPTER 7 DESIGN CRITERIA AND BASIS OF COST ESTIMATES One of the purposes of this report is to lay out the various construction phases in sufficient detail to permit comparisons of performance, and cost of both construction and operation. To make such layouts it is necessary, first, to develop criteria applicable to the preliminary design of all pumping facilities, and second, to develop basic cost data for elements of the several alternative projects. Preliminary Layouts Design criteria and basic cost data presented herein apply to preliminary design or layout of wastewater pumping station modifications. In layouts of this type, detailed construction drawings and specifications are not required. It is necessary that a reasonably close approximation of the size, location, type of construction, and cost of the various facilities be developed, and that this informa- tion be given in sufficient detail to permit design evaluations. It is expected that a small amount of relocation and resizing of some of the facilities will be required at a later date as a result of detailed engineering analysis during the preparation of construction drawings and specifications. Design Period The various components of the wastewater pumping facilities considered in this report have been laid out to serve development of the study area to the year 2000. It does not follow, however, that all improvements need to be made in the immediate future; in most cases improvements can be effectively phased to meet Table 7-1. Summary of Unit Design Criteria Item Wastewater volume Domestic Average flow, gcd Peak flow Commercial and Industrial Average flow, gad Peak flow, gad Storm water inflow, gad Infiltration Direct storm inflow gcd = gallons per capita per day gad = gallons per acre per day Factor 90 a 2,500 a 1, 000 250 750 a Dependent upon magnitude of contributory population. demands as they develop. In the case of pumping stations, economy dictates that they be constructed so as to be readily enlarged. Influent structures, buildings and principal conduits should be designed for long-term requirements, whereas mechanical equipment, such as pumps and motors, may be installed at various phases of development. Design Criteria General design loadings and unit quantities, developed in Chapter 4, are summarized in Table 7-1. Reference should be made to that chapter for informa- tion on the assumtions and conditions Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations upon which the design loadings are based. As a reference datum, the United States Geological Survey (USGS) mean 61 sea level datum has been used for all layout work and design computations. Preliminary force main routes, lengths and ground elevations were determined from topographic maps, the principal source being those of the USGS at a scale of 1:24,000 (l" = 2000'). Force Mains. Force mains, unlike gravity sewers, always flow full and must be designed with proper velocities to prevent the deposition of sol ids. To insure an adequate minimum velocity it is necessary in many cases to resort to the use of multiple lines. Inlet and outlet structures provide for the use of one line until the flow increases to the point where the capacity of an additional line is needed. Since the design flow is divided between two or more lines operating under pressure, force mains and inverted siphons are commonly of smaller size than the adj a cent gravity sewer. Force ma ins are normally constructed of concrete cylinder pipe, concrete- lined and coated welded steel pipe, cast iron pipe or asbestos-cement pipe. The most suitable material for a specific installation is usually determined during final design. Diameters of force mains were calculated by determining the most economical combination of pipe diameter and pump size which would maintain velocities greater than 2 fps and less than 8 fps. Pumping Stations. Pumping stations are designed to handle PWWF from their tributary areas. Although pumping units may be installed incrementally as required by increases in flow, structures will be designed for the estimated population at about the year 2000. Pumping units for major stations are centrifugal wastewater pumps with variable speed drives to minimize wet well size and minimize corrosion and odor problems. The number of pumping units installed should be sufficient to pump the design flow with one unit out of service. Standby power units are provided where bypassing cannot be allowed or where 1 ine storage cannot accommodate flow during temporary power outages. Design of pumping stations must provide for complete separation of wet and dry wells with easy access to both. This avoids flooding and the subsequent damage to mechanical and electrical equipment in the event of a major power failure. Design also includes automatic control equipment, metering devices, adequate ventilation to prevent condensation on walls and equipment, and all other necessary appurtenances. Construction Costs For estimating purposes, prices of comparable work were obtained from available sources of current information. Manufacturers and suppliers of material and equipment were consulted on specific questions. Costs of pumping stations and force mains, derived from actual projects designed by Brown and Caldwell, were relied upon heavily but were adjusted to local conditions. 62 Design Criteria and Basis of Cost Estimates 4400 4000 800 ~ 400 l!J!JO - LOS ANGELES ,/ / 'r I AREA-,.... " I \ \ { UNITED STATES ~ AVERAGE- .J ~ ~ :l,--.,,... ,.,,,. ~ ~ 1913 lfl>EX • IOO /970 YEAR I I ! . I ! I . i Fig. 7-1. EM R Construction Cost Index I , I if l9IIO In considering the estimates, it is important to realize that changes during final design will alter the totals to some degree, and that future changes in the cost of material, labor and equipment may cause comparable changes in costs pre- sented herein. On the other hand, since the relative economy of successive con- struction stages can be expected to change only slightly with an increase or decrease in general construction costs, decisions based on present comparisons should rem a in val id. Construction costs can be ex- pected to undergo long term changes in keeping with corresponding changes in the national economy. The best avail- able barometer of these changes is the Engineering News-Record (ENR) con- struction cost index. It is computed from prices of structural steel, portland cement, lumber, and common labor, and is based on a value of 100 in the year 1913. As indicated by the curve in Fig. 7-1, which portrays the trend of the ENR index since 1950, construction costs have been steadily increasing for many years. This figure shows the rate of increase of the Los Angeles area ENR index, which is considered to be representative of construction cost increases in San Diego County. For purposes of comparison, estimated costs of alternative plans are based on the current ENR index of 2200. In any event, costs used herein may be related to those at any time in the past or future by applying the ratio of the then prevailing EN R index to the index used herein. For example, the costs of the ini- tial phases of construction presented in Chapter 10 will be based upon the ENR index estimated to prevail during the mid-point of construction. Unit prices given in this chapter include contractor's overhead and profit, but do not include engineering, construction contingencies, rights-of-way, land acquisition or legal costs. Separate allowances are made to cover these items. It should be noted that the unit prices used in preparing preliminary estimates represent average bidding conditions for many projects. For this reason, it is entirely possible that actual construction bids for a given project may be lower or higher than the unit prices used herein. Although additive or deductive items are applied where believed necessary to cover special conditions, the preliminary estimates are not presumed to be as accurate as estimates prepared during final design. Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations 63 Force Ma ins. Unit costs for force mains are based upon the use of cast iron, lined and coated steel, asbestos-cement or concrete cylinder pipe. Costs include pipe, excavation, laying fittings, select bedding and initial backfill, testing, cleanup and contractor's overhead and profit as shown in Table 7-2. Additive costs for pavement replacement, interference with utilities and traffic control are 1 isted separately and must be added where applicable. Costs are based upon dry or moderately wet conditions and a minimum four foot depth of cover. Estimates for unusually wet or difficult construction conditions have been developed specifically for each case. Table 7-2. Unit Costs of Force Mains Interference with Basic construction Pavement replacement, utilities and traffic Pipe size, cost, dollars per add dollars control,add dollars inches lineal foot per lineal foot per lineal foot 6 13.60 2.50 2.25 8 16.80 2.50 2.25 10 20. 40 2.50 2.25 12 22.30 3.00 2.25 14 24.60 3.00 2.25 16 27. 20 3. 00 2. 50 18 28.50 3.25 2. 50 21 32.00 3. 25 2. 50 24 35.60 4.00 2.50 27 39.50 4.00 3.00 30 43.00 4.25 3.00 33 49. 20 4.50 3.00 36 55.70 5.00 3.00 39 62.80 5.50 3.00 42 69.60 6. 00 3.00 a Costs are based on an ENR Construction Cost Index of 2200 and provide for the use of class 150 cast iron, cement lined and coated steel, or asbestos-cement pressure pipe up to 12 inches in diameter, and concrete cylinder pipe for larger sizes. For pressures requiring pipe rated above class 150, add $ 0.15 per inch of diameter per lineal foot. Costs include pipe, excavation, laying and jointing, fittings, backfill, testing, cleanup and contractor's overhead and profit. Bedding and initial backfill is select imported granular material and subsequent backfill is native material. Costs are based on pipe laid with a minimum cover of four feet in a dry or moderately wet trench. Costs do not include allowance for construction contingencies, engineering or right-of-way acquisition. Pumping Stations. Of all the components of a sewerage system, major pumping stations are likely to exhibit the greatest variation in construction cost. Factors such as foundation conditions, groundwater, and location relative to other structures cannot always be accurately assessed in preparation of pre- liminary layouts. The costs for major pumping stations as presented in Fig. 7-2 are representative of the higher range of costs likely to be encountered. Under favorable construction conditions, bid prices may be substantially lower than shown. Costs for pumping stations are based on peak rates of flow with sufficient pumping capacity to handle peak flows with one pumping unit out of service. Unit costs also reflect structural, mechanical, electrical and architectural design criteria previously established. In addition, allowances are made for fully automatic control of pumping functions, and for suitable landscaping and fencing. 64 /0.0 7.0 5.0 3.0 2.0 1.0 !Q 7.0 "'t ....J ~ ~ 5.0 ~ ~ ....J 3.0 ;;:! i ..... (IJ 2.0 ~ 1.0 07 0.5 0.3 0.2 0./ Design Criteria and Basis of Cost Estimates / V V / ~v V ./ I/ ,.V I/ "-RAW WASTEWATER PUMPING STATIONS / V V 2 3 .,V V 5 7 /0 20 30 50 70 100 PUMPING CAPACITY, mgd-PEAK WET WEATHER FLOW 200 300 Costs are based on an ENR Construction Cost Index of 2200. Pumping station enlargements to twice the initial capacity costs are 20 percent less than those shown. Costs do not include special foundation condi- tions, construction contingencies, engineering or site acquisition. Fig. 7-2. Construction Cost of Wastewater Pumping Stations 500 Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations It should also be noted that modifications to existing facilities can be as expensive as the basic construction cost of an entirely new facility. This is primarily due to the need to construct the modifications while maintaining an operating facility. 65 Engineering Costs. The cost of engineering services for major construction projects may include special investigations, predesign reports, surveys, founda- tion exploration, location of interferring utilities, detailed design preparation of contract drawings and specifications, construction inspection, material testing, and final inspection of the completed work. Depending on the size and type of the,project, total engineering costs may range from 7 to 15 percent of the contract cost. The lower percentage applies to large projects and those which do not require a large amount of preliminary investigation. The higher percentage applies to smaller projects or to those which require a large amount of prelimin- ary investigation. For the purpose of this report, engineering costs are based on 12 percent of the contract costs. When applied in sequence, construction contingencies and engineering amount to nearly 30 percent of the basic contract cost. An allowance of 30 percent is included in the preliminary cost estimates developed in this report. Annual Costs To permit a true economic evaluation, alternative projects are compared on an annual cost basis as well as on a first cost basis. Annual costs take into account operation, maintenance, administration, depreciation, and interest on borrowed capital. When factors other than annual costs are involved, they also must be evaluated before reaching the final decision on which alternative is best. Interest and Depreciation. Interest rate for municipal bonds is taken at 7 percent. If the current trend continues there may be a period of higher interest rates; however, it is expected that the average interest rate over the amortization period of the major structures will not exceed 7 percent. Depreciation was com- puted by the sinking fund method using 7 percent interest. Annual interest and depreciation is commonly referred to as "fixed cost" and may be computed by using the capital recovery factor found in most interest tables. The economic life of force mains is generally assumed to be 50 years, while pumping stations are assigned a life of 30 years to take into account the replacement of mechanical equipment prior to the full depreciation of structures. Replacement of mechanical equipment is assumed to be due only to obsolescence, inadequacy or major deterioration. The cost of repair and minor replacements is included under operation and maintenance. The economic life assigned to the various units is only to facilitate the cost comparisons and does not necessarily reflect the true useful life. There are many sanitary sewers in service which are over 50 years old and some have been in service more than 100 years, while pumping station structures can be expected to have a useful life in excess of 30 years. 66 Design Criteria and Basis of Cost Estimates Operation and Maintenance. Operation and maintenance costs include all costs for labor, power, supplies, laboratory control and monitoring, administra- tion, and incidental cost chargeable to the various components of the sewerage system. As with costs for construction, operation and maintenance costs are based on current price and wage levels. Pipelines. The annual operation and maintenance cost for sewers, force mains and inverted siphons is taken at$ 250 per mile. This cost represents the average for relatively extensive trunk systems and may not be applicable to small individual segments. Also, the cost is assumed to be the average for many years of operation and variations from year to year may be expected. Pumping Stations. Total operation and maintenance costs for pumping sta- tions, shown on Fig. 7-3, are the sum of ( 1) power costs for the ADWF and pumping head, and (2) other operation and maintenance costs which are related to the peak flow which the station is designed to accommodate. The curve for other operation and maintenance cost is based on normally unattended stations and includes allowances for labor, supplies, administration, replacement parts and repairs necessary to keep pumping and other mechanical units in effective operational condition. 10,000 7,000 5,000 3,000 2,000 1,000 700 500 300 IQ 200 ~ -.J ~ ~ /00 ~ § 70 1-: 1-,.• 50 (I) 8 -.J 30 ;§ ~ ~ 20 /0 7 5 2 I / / / / /~ -1/ / / / Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations / / V / / TOTAL DYNAMIC HEAD--, / \ ✓ / / / / V V / 7 jY V /" / ~v 1,1" 'kV V V V / ,/ / / /v J/ / / 7 V vy , ,V v // / / l>"_/ // / / / / / /! / / ~7 / ,/ / / / , / V ~1' / ~ /.. / / 17 V / ::,' / / // / ~7 //, ~ / ~ V: ~ I/ /' ./ 1// ~v 7 POWER COSTS(AVERAGE FLOW) / ----OPERATION AND MAINTENANCE COSTS EXCLUSIVE OF POWER-V (PEAK FLOW) I 2 3 5 7 /0 20 30 50 70 /00 200 300 500 WASTEWATER FLOW, mgd Fig. 7-3. Operating Costs of Wastewater Pumping Stations 67 68 CHAPTER 8 PROJECT ALTERNATIVE ANALYSIS Presented below is a description, comparison and evaluation of alternatives, leading to a selection of the recommended plan of action. An effort was made to consider all reasonable alternatives in the development of a solution to the prob- lems facing the study area. As indicated in the previous sections, Vista Sanita- tion District and Carlsbad have inadequate pumping facilities to convey future wastewater flows to the Encina WPCF. Action must be taken to insure that Buena Vista Lagoon and Agua Hedionda Lagoon are protected from wastewater discharges due to overflows. INITIAL SCREENING OF ALTERNATIVES In considering alternative pumping station projects, development of alterna- tive plans is generally limited to (1) the location of the sta1.:ion, (2) the ultimate capacity, ( 3) staging of capacity, and (4) the necessity of the project. The location of both the Buena Vista and Agua Hedionda pumping stations has already been established and cannot be altered without considerable re vis ion of the existing sewerage system. Furthermore, locations of the pumping stations are at optimum points of the system to accommodate oravity flow. There is, therefore, no justification in considering alternative locations and abandoning existing fac- ilities. The ultimate flow capacity and phasing of capacity has been considered in the initial design phase of the pumping stations. Physically, the structures which house the mechanical equipment limit the ultimate capacity to a range dependent upon internal modifications. Original plans for phasirg of the facilities, however, can be altered by modifications or replacement of pumps. Due to physical con- straints in the structure, each phase is 1 imited to a given range of capacity. Aspects of ultimate capacity and incremental expansion will be considered in evaluating alternative projects for both pumping stations. The alternative of no project could only be justified by upstream treatment and reclamation or by allowing no further growth in the area. Not undertaking the enlargement is a costly, and unacceptable alternative in view of the existing regional sewerage system and is not compatible with recently adopted water quality management plans for San Diego County. Reclamation and reuse of all or portions of the wastewater from the study area cannot be considered as an alterna- tive to increasing the capacity of the stations since there is no demand for re- claimed water. Furthermore, regulatory agencies and informed laymen alike are aware of the need for a fail-safe system for disposing the entire wastewater flow from an area during emergency conditions, when treatment facilities are unable Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations 69 to produce an effluent of the required quality for reuse, or during periods of low or no demand for reclaimed water. Thus, a means of disposing wastewater flows in a safe and ecologically sound manner is a necessary part of any reclamation scheme. Modifications of the stations enable peak flows of wastewater to be transported from two separate sewerage agencies to a regional facility for treat- ment and disposal. Pumping station enlargements and improvements therefore, are compatible with any future plans for upstream reclamation and reuse of waste- water. The alternative of no modification to either pumping station would assume that -the existing stations will be utilized as they are for 3 to 5 years into the future. The selection of this alternative would mean that immediate capital expenditures for renovation would not be required, but would probably cause additional costs in the future if growth were to continue. The cost of flooding out a pumping station in a low lying area during PWWF periods is expensive. A conservative estimate of this cost might be equivalent to the cost of a new pumping facility. Conse- quently, a no project alternative would probably be the most expensive in the long- term and would not present a solution to the existing problem. Furthermore, the lagoons and adjacent areas would not be adequately protected against wastewater overflows without additional pumping capacity. Overflows would cause adverse aesthetic and public health impacts and the alternative of no project is considered unacceptable for those reasons. DESCRIPTION OF ALTERNATIVES Based on the preceding discussion, alternatives for each of the two pumping stations were developed and investigated with regard to ultimate and incremental capacity. Alternative projects presented herein provide increased capacity by expansion based on ( 1) the existing design, and (2) a modified design. Alternatives formulated herein have been sized to provide capacity for wastewater flows projected to about the year 2000. For plans in which expansion follows the existing pumping station design, there is insufficient capacity for projected flows. In order to compare alternatives on an equitable basis, there- fore, parallel pumping facilities will be provided to increase the capacity of the systems to a level similar to the modified design alternatives. Buena Vista Pumping Station The following discussion describes alternatives considered in detail for the Buena Vista Pumping Station. Plan BVl -Existing Design Expansion. As shown previously in Fig. 5-2, there are two available positions in the pumping station for the installation of additional pumps. There are 8-inch suction nozzles and 12-inch headers already installed with blind flanges covering them. Two more 8-inch suction, 8-inch discharge pumps can be installed if the pumping station and force main are shut down and drained for a period long enough to install four shut-off valves. The pumping station must be inoperative while piping connections are accomplished 70 Project Alternative Analysis in order to prevent the dry well from being flooded, Assuming that no force main addition is made at this time, the addition of two pumps will increase the plant capacity from the present 3200 gpm (4.61 mgd) to 4400 gpm (6.34 mgd) with one standby pump, for a total flow increase of 1200 gprn. The system curve for this alternative is shown in Fia. 8-1 in which the capacity of the system may be com- pared relative to the present PWWF and that anticipated in 2000. Static head and dynamic head losses in the existing 16-inch diameter force main and in two parallel 16-inch diameter lines are shown in the system curve. The two parallel curves indicate differences between the high and low levels in the wet well. Pump characteristics following modifications for suction-discharge losses in the associated piping are also shown in the figure. The maximum pumping capacity under the given conditions is indicated at the point where the system and modified characteristic curves cross. The dashed line indicates the pump characteristic curve prior to the addition of suction-discharge piping losses. The above pre- sentation will be used in developing and evaluating the system curves of each alternative presented in this chapter. If an immediate program is undertaken to complete the partially constructed parallel 16-inch force main, the flow capacity could be increased again. With five pumps, all operating with no back-up in case of failure, and two parallel 16- inch force mains, the maximum flow would be 5600 gpm (8.06 mgd). With four 180..----r---r-------.---.----r---T""------.---.----r---r------r--r-----r----r--,---, 160 140 1-.. 120 ~ ~ ~ 100 ~ l: -.J ~ 80 ~ 60 LL 3: C er I- 40 z LLJ CJ) LLJ er Q. 200 I 2 3 4 5 LL 3: 3: Q. I-z LLJ CJ) LLJ er Q. SINGLE 1611 FORCE MAIN PARALLEL 1611 MAINS SYSTEM-HEAD CURVES BUENA VISTA FORCE MAIN AND PUMPING STATION NOTE: C = 120 6 7 8 g DISCHARGE IN GPMx/O00 10 II 12 fig. 8-1. System -Head Curves -.Alternative BVl 14 LL 3:· 3:. a.., c. LLJ I-• u LLJ' -,, 0 er· a... Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations 71 pumps in operation, the normal maximum rated capacity, the capacity would be 5200 gpm (7. 48 mgd), representing an increase of 2000 gpm (2. 88 mgd) over the existing pumping capacity. A standby power supply would be provided by a 400 I& generator set mounted next to the station in a weatherproof enclosure. The project cost to this point is$ 400,100 corresponding to an incremental unit cost of$ 200.05/gpm ($ 138,900/mgd). Based on projected PWWF to the Buena Vista Pumping Station, modification of the existing facilities by means of this alternative would not provide sufficient capacity for PWWF anticipated at the time of construction. A parallel 12. 3 mgd cap- acity station and 21-inch force main, therefore, would also be required for capacity equivalent to Alternative BV2. The project cost of these additional facilities would be$1,217,600 resulting in a total project cost of$ 1,617,700 or a total incremen- tal unit cost of$ l66.03per gpm ($ 115,500/mgd). Plan BV2 -Modified Design Expansion. Alternative BV2 would provide for extensive modifications to the existing facility in order to accommodate the pro- jected wastewater flows to the year 1995. Plan BV2 would be constructed in three increments to minimize initial expenditures and it is recommended that Phases I, II and III be performed as required in order to provide adequate capacity for pro- jected wastewater flows. Sufficient standby power will also be provided incre- mentally during appropriate construction phases to completely run the pumping station for three days with no outside assistance. Phase I of the proposed modifications consists of series installation of the parallel 24-inch force main and pumping station additions. Addition of the parallel force main will increase the existing pumping capacity to 4400 gpm (6.34 mgd) with two pumps on and 6100 gpm (8. 78 mgd) capacity with all three pumps in operation. Two new 10 x 10 x 21 pumps will be installed to supplement the existing pumps and extensive modifications will be made to the existing wet well, including modifications to the suction nozzles of the new pumps. The capacity at this point will be 9000 gpm (13 mgd) with one new pump and all three existing pumps in operation, while a capacity of 9600 gpm (13.8 mgd) could be realized with all five pumps operating. This capacity corresponds closely with the existing capacity of the receiving interceptor sewer system in the City of Carlsbad. A single 225 KV/ turbine generator will also be installed as a standby power source. Phase II will include installation of another 10 x 10 x 21 pump in place of an existing pump and the corresponding suction nozzle modification in the wet well. The capacity will thereby be increased to (1) 10,500 gpm (15 .1 mgd) with two new 10 x 10 x 21 pumps and two existing pumps in operation, and (2) 11,500 gpm (16. 6) with the three new 10 x 10 x 21 pumps operating with the two existing pumps serving as standby. The existing header will be replaced on the side with the two newer pumps. Phase III will complete the sequencing of the project with the installation of two additional 10 x 10 x 21 pumps to replace the remaining two original pumps ,a new piping header, and another 225 KV/ turbine generator for additional standby power. Maximum flow capacity at this time would be 13,500 gpm (19.4 mgd). 72 160 140 1-.. 120 ~ ~ ~ 100 ~ l: -.J ~ 80 ~ 60 u. 3: a <I I- 40 z IJ.J CJ) IJ.J a: a.. 2 3 4 Project Alternative Analysis 5 u. 3: 3: a.. I-z IJ.J (J) IJ.J a: a.. SYSTEM-HEAD CURVES BUENA VISTA FORCE MAIN AND PUMPING STATION NOTE: C = 120 6 7 8 g DISCHARGE IN GPMx/000 10 II 12 Fig. 8-2. System -Head Curves -Alternative BV2 14 CL. <I. IJ.J >-. u. 3:• 3:. a... a. IJ.J I-· u w· ""), 0 a:· a... 15 The system curve is shown in Fig. 8-2. This would be a total increase of 10,300 gpm (14. 8 mgd) and the total project cost would be $ 1,151,200 corresponding to an incremental cost of$ 111. 66/gpm, ($ 77, 500/mgd). The construction is phased in such a way that the pumping station would be in operation at all times, except for brief -periods of low flow while barrier installations are made in the wet well. Agua Hedionda Pumping Station The following alternatives were considered for the Agua Hedionda Pumping Station. Plan AHl -Existing Design Expansion. As mentioned previously in Chapter 5, the impeller in the existing constant speed pump 3 has recently been changed from an 11 !11 to a 11G 11 type. Modification of the impeller type increased the total pumping capacity from 6,500 gpm (9. 4 mgd) to 7,200 gpm (10. 4 mgd) with one pump serving as standby. Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations 73 An additional modification would provide for the ins ta lla tion of an identical fourth 10 x 8 x 13 pump in the position provided. Installation of the pump requires draining the wet well and blocking the inlet pipe to install a plug valve on the wet well suction nozzle. This can be accomplished during a period of low flow. This modification would increase the pumping capacity of the station with one pump as standby from the existing 7200 gpm (10. 4 mgd} to 10,400 gpm (15. O mgd}. The system curve is shown as fig. 8-3. With a 225 KVJ gas turbine generator included to provide standby power, the project cost to this point would be $ 172,200 cor- responding to an incremental cost of$ 53. 93/gpm ($ 37, 500/mgd). 80 70 I,.. ~ I( ~ ~ ~ ~ ..... 40 ~ ~ 30 20 10 SYSTEM -HEAD CURVES AGUA HEDIONDA FORCE MAIN AND PUMPING STATION NOTE: C = 120 a L&.J' ...... u l.&.J• ..., o· a:. Cl. 2 3 4 5 6 7 8 9 I II 12 /3 14 15 /6 17 /8 19 20 21 22 23 DISCHARGE IN GPM x 1000 Fig. 8-3. System -Head Curves -Alternative AH 1 Based on projected PWWF to the Agua Hedionda pumping station, modification of the existing facilities by means of this alternative would not provide sufficient capacity for PWWF beyond the year 1980. A parallel 16 mgd capacity station and 24-inch force main would be required to provide capacity equivalent to Alternative AH2 near the year 2000. The project cost of these additional facilities would be $ 1,073,800 resulting in a total project cost of$ 1,246,000 or an incremental cost of $ 87. 09/gpm ($ 60, 500/mgd}. 74 Project Alternative Analysis Plan AH2 -Modified Design Expansion. This alternative would provide for extensive modifications to the existing facility in order to accommodate the pro- jected wastewater flow to the year 2000. Plan AH2 is to be constructed in phases to minimize initial expenditures with Phase I to be completed as soon as possible. Furthermore, enough standby power will be provided at each phase to completely run the pumping station for three days minimum, with no exterior power sources. During Phase I, a single 12 x 12 x 21 pump will be installed with its motor exposed at ground level. The standby engine will be removed and replaced with a 225 K:,/11 turbine generator, located outside the station, while new motor controls will be located inside the existing structure above ground level. A new expanded ventilation system will also be installed. The capacity after the completion of Phase I will be 10,400 gpm (15.0 mgd) with three existing pumps in operation. Phase II would commence shortly after the completion of Phase I in order to provide adequate backup pumping capability. Another 12 x 12 x 21 pump will be added along with the corresponding wet well modifications. This phase also in- cludes 150 feet of parallel 18-inch force main to lower pipeline velocities at high flow conditions. At this point the pumping capacity will have increased to 16,200 gpm (23. 3 mgd) with two existing pumps serving as backup. Flexibility in the operation of the pumping station is available due to the matched design capa- cities of all the pumps. Construction of Phases I and II would provide adequate capacity for PWWF to the year 1989. Phase III involves replacement of the two smaller original pumps with two more 12 x 12 x 21 pumps and construction of the remaining suction nozzle improve- ments .All connections will be made into the existing 18-inch diameter header. The maximum pumping capability at this time will be 21,500 gpm (31.0 mgd) with only three pumps in operation at any single time and would be adequate to about the year 1998. An additional 350 K:-N generator would also be installed. The system curve associated with these improvements is shown in Fig. 8-4. The total project cost will be$ 757,200 resulting in a unit cost of$ 52.87/gpm ($ 36, 716/mgd). ..... ~ I( ~ ~ ~ :t: ...... ~ ~ Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations 90 ,------,----,----,----r---.---,---,,----r--r----,---,-----,---,---,----,------,---.--.------..--r--~--,--......, 80 70 60 50 40 30 20 10 2 I-z LL.ILL ~3 cro Cl.<l 3 4 I-z LL.ILL Ul3 ~3 Cl.Cl. 5 6 7 8 9 I II 12 SYSTEM -HEAD CURVES AGUA HEDIONDA FORCE MAIN AND PUMPING STATION NOTE: C = 120 /3 /4 15 /6 17 /8 DISCHARGE IN GPM x 1000 Fig. 8-4. System -Head Curves -Alternative AH2 /9 COMPARISON AND EVALUATION OF ALTERNATIVE PLANS 20 21 0 LL.I' 1-, (.) LL.I• -:, o· er. Cl. 22 23 75 In general, the principal factor to be considered in the comparison of several alternatives to perform a given function is that of cost, both the initial project cost and the total annual cost. Cost comparisons are made on the bas is of total costs for the design capacity of 20 mgd for the Buena Vista Pumping Station and 31 mgd for the Agua Hedionda Pumping Station. These are the ultimate capacities of the alternatives under consideration. Consideration must also be given, however, to the degree which each alternative plan meets the specified objectives of the water quality management plan for the study area. Careful evaluation must be made of environmental and socio-economic factors which cannot be measured by cost alone. Economic Factors In general, the alternative wastewater projects are evaluated economically from the standpoint of both project and annual costs. Annual costs of the 76 Project Alternative Analysis alternative plans for each pumping station include similar components of opera- tion and maintenance costs as well as power costs. The similarity in cost occurs since both alternative plans provide the same capacity and have the same static lift for the particular pumping station. The contributions to annual costs which result from capital recovery for individual alternatives, however, are different due to the different total capital cost of each alternative. All operating and maintenance costs are based on the ADWF which corresponds to the PWWF capacity for each alternative, and were obtained from Fig. 7-3 of this report. As is noted in Table 8-1, Plan BV2 is 29 percent less costly than Plan BVl and'Plan AH2 is 39 percent less costly than Plan AH 1, based upon total capital costs. Although power and operating costs are proportional to capacity, the total annual costs of Plans BV2 and Plan AH2 are also lower than for the corres- ponding alternatives due to higher amortized costs and additional maintenance costs for the two pumping stations. Table 8-1. Economic Comparison of Alternatives, dol I ors Pumping station alternatives Cost factor Plan BV 1 Plan BV 2 Plan AH 1 Plan AH 2 Capital costsa Pumping stations 1,238,900 941,300 1,234,400 749,800 Force mains 378,800 209,900 11,600 7,400 Total capital cost 1,617,700 1,151,200 1,246,000 757,200 Annual cost Capital recoveryb 133,600 95,100 102,900 62,500 Maintenance 13,000 11,000 17,900 14, 000 Operation (power)c 23,000 23,000 9,500 9,500 Tota 1 annual cost 169,600 129,100 130,300 86,000 Total capacity mgd, (year) (1996) 19.4 (1996) 19.4 (1998) 31.0 (1998) 31.0 a Based on ENR Construction Cost Index of 2200. Includes allowance for contingencies, engineering and project administration. b 30-year amortization at 7 percent interest. c Based upon ADWF and Fig. 7-3. Environmental and Socio-Economic Factors The capability of each of the alternatives to achieve the following environ- mental and socio-economic objectives was also evaluated: Environmental Impact Protection of the Pacific Ocean Protection of Buena Vista Lagoon Protection of Agua Hed ionda Lagoon Protection of groundwater basins within the study area A high "Expected Performance/Total Cost" ratio compared to other alternative plans Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations Regional Land Use 77 Compatibility with existing plans for regional land use and development Accomodation of planned population growth Population Sensitivity Ability to adapt to population growth rate changes and remain operable Flexibility and Reliability Amenability to revision to accommodate changing patterns of urban development with no compromise of performance A high degree of assurance of expected project performance Minimum consequences from system failures due to a natural disaster or catastrophe Minimum mechanical and process failures, minimum consequences from such occurrences Implementation Capability of rapid implementation Minimum legislative, financial, and logistical obstacles Local governmental acceptance Public Reaction Attractiveness to the public Acceptance of the design and reports by local public groups Compatibility Accomplishment of objectives of interim water quality control plan Consistency with established regulatory agency policies Each of these factors was evaluated individually with respect to the alterna- tive plans, and a matrix developed as shown in. Table 8-2. Numerical values ranging from zero to four were assigned. A rating of zero or poor indicates a project which meets minimum program criteria but is clearly inferior to alternative projects or is of doubtful long-term suitability. Increasing numbers are used to indicate increasing relative value for performance and suitability. A rating of four or excellent indicates a project which will provide superior performance with the capability of meeting or exceeding all anticipated program criteria including long-term suitability. The plan which has the highest total is therefore ranked first with regard to socio-economic and environmental considerations. Ranking alternative projects in this manner is clearly a subjective process. It is used here as a simple means of summarizing our judgement regarding the intangible merits of each plan. 78 Project Alternative Analysis Table 8-2. Evaluation of Environmental and Socio-Economic Factors Buena Vista Pumping Station Agua Hedionda Pumping Station Factor Plan BV 1 Plan BV 2 Plan AH 1 Plan AH 2 Environmental impact Marginal Good Marginal Excellent Regional land use Adequate Good Adequate Good Population sensitivity Good Excellent Good Excellent Flexibility and reliability Good Excellent Good Excellent Implementation Adequate Good Adequate Good Public reaction Marginal Good Adequate Good Compatibility Excellent Excellent Excellent Excellent Overall ratinga Adequate Good Adequate Excellent a Based on the average of ratings given to all factors with numerical equivalencies: Poor= 0, Marginal= 1, Adequate= 2, Good= 3, Excellent= 4. Rationale used in developing the relative ranking of the alternative plans for each of the environmental factors is discussed in the following paragraphs. Environmental Impact. The basic nature of the alternatives indicates that the construction of additional pumping stations will have significantly greater environmental impact than modification of existing facilities. A detailed evalua- tion on the environment is presented in Chapter 9. The additional necessity of a site and pipeline route for Plans BVl and AHl will inevitably create an environ- mental problem. Since both sets of alternatives offer adequate pumping capacity, no significant danger of internal flooding is incurred by any alternative. Due to the higher initial capital costs of Plans BVl and AHl, however, these plans will have a lower "expected performance/total cost" ratio. Regional Land Use. All of the plans will provide additional wastewater pumping capacity and allow future population expansion in the service areas. Since the additional capacity is being provided to accomoda te planned expansion in the area, all plans are compatible with planned regional land usage. Through the issuance of building permits, the local cities can regulate construction and defer the promotion of unwanted population growth. For the above reasons, all four plans are rated equal relative to land use development. An adverse factor, however, occurs when Plans BVl and AHl necessitate acquisition of land that might possibly have better uses to the community, for additional parallel pumping stations. ) Population Sensitivity. The ability to adapt to changes in the rate of population growth is related primarily to pumping capacity. All plans include variable speed pumps which can have lower outputs and provide for phasing of future construction as dictated by increases in population. Therefore, all plans offer the ability to respond to demands for wastewater pumping capacity without providing excessive capacity at each phase expansion. Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations 79 Flexibility and Reliability. Any construction project that is designed to have phases which are based on population growth, provides for future flexibility. As set forth in Plans BVl and AH!, if the existing pumping stations were expanded in accordance with the original designs, the available capacity in either pumping station would be severely 1 im ited. These plans are, therefore, inflexible in responding to needs and new pumping stations would have to be provided in the future. The phased construction programs proposed in Plans BV2 and AH2 are capable of providing adequate capacity in increments as required for expanded population growth to the period 1995 -2000. Smaller gravity flow conveyance systems can generally be expected to perform to their design capacity more reliably and consistently than systems which require pumping. This advantage, however, is insignificant in large conveyance systems where duplication of equipment and control circuitry can virtually insure proper performance. Furthermore, the Encina Joint Sewerage System has been established on a regional basis and wastewater must be pumped to the joint treatment facility. With regard to reliability, therefore, all plans are rated equally. Implementation. The ease of implementation is based upon three factors; cost, amount of necessary construction, and public acceptance. Since the original steps of Plans BVl and AH 1 are relatively simple additions to the existing configurations, they would be much easier to implement than the larger construc- tion projects contained in the corresponding modified design alternatives. Siting and construction of an additional pumping station as called for in BVl and AHl may be extremely difficult, however, especially adjacent to Buena Vista Lagoon. Alternative plans BV2 and AH2 are lower in total project cost and will therefore be easier for the individual agencies to finance in the long-term. Public acceptance of the alternative projects is discussed below. Public Reaction. Due to the sensitive nature of the surroundings and the length of the necessary force main addition it is probable that some adverse public reaction might be associated with the expansion of capacity in the Buena Vista Pumping Station. The relative proximity of homes and the bird sanctuary will make any construction difficult to accept. Conversely, Agua Hedionda Pumping Station is located on private property and little opposition to its expansion is foreseen. Construction of additional pumping stations at either site as set forth in Plans BVl and AH 1 would create more problems than modification of the existing facilities with regard to public reaction. Compatibil\ty. State regulatory agencies are requiring consolidation of wastewater management systems in all cases where it is feasible and desirable to accomplish good water quality management based upon long-range economic and water quality benefits to an entire basin. On this basis, it is reasonable to assume that all alternatives will provide equal water quality protection and each would have the acceptance of regulatory agencies. 80 Project Alternative Analysis Selection of Recommended Plan In the foregoing discussion of economic and environmental factors it has been shown that of the alternative plans considered, Plans BV2 and AH2 are the best plans with regard to ultimate costs and environmental considerations. Under these plans, both Buena Vista Pumping Station and Agua Hedionda Pumping Station will be expanded in phases to meet the projected capacity requirements in the period 1995 -2000. CHAPTER 9 ENVIRONMENTAL IMPACT STATEMENT 81 The purpose of the proposed projects is to provide additional wastewater pumping capacity in order to meet the expected future growth of Vista Sanitation District and the City of Carlsbad. The environmental impact statement presented below follows the format recommended by the SWRCB and the EPA. Both of the proposed projects include expansions of pumping capacity by internal pumping station modifications and by the addition of parallel force mains. The facilities under consideration are the Buena Vista Pumping Station and the Agua Hedionda Pumping Station, both of which are adjacent to natural lagoons. Although alternatives which respond to projected long-term needs have been devel- oped, this assessment of environmental impact will be limited to Phase I improve- ments for each pumping station project. Probable Impacts on the Environment The pumping station modifications and enlargements will result in several impacts on the City of Carlsbad environment. Long-term and short-term impacts of the proposed projects are summarized below. Long-term Impacts. The proposed projects are expected to have several long-term impacts which are as follows: 1 • Current State standards for receiving water quality will continue to be met by providing for the transmission of wastewater to a location which can provide adequate treatment prior to discharge. 2. There will be a permanent increase in electrical power required at both pumping station sites. About 225 kilowatts of power will be required for the Buena Vista and Agua Hedionda stations under peak loads of about 13 and 15 mgd, respectively. 3 • Operation of additional pumps at both pumping stations will create additional noise sources within the enclosed pumping station structures, however, no additional noise will be detected outside of the structures. 4. Odors characteristic of wastewater may be detectable only at the pumping station sites. Odors will be minimized through use of air injection and dispersion techniques. Improvement and Enlargement of the Buena Vista 82 and Agua Hedionda Pumping Stations 5. Gaseous exhaust emissions at the site will be increased slightly during use of a gas-turbine generator which burns diesel fuel for standby power. Expected usage is once a week for one hour except for periods of emergency such as power failures. 6. Population increases which will be supported by the increase in wastewater handling capacity will have the following long-range impacts: a. Increases in vehicular traffic throughout the study area. b. Increases in the development of presently undeveloped land for residential, commercial and industrial purposes. c. Increases in air contaminant emissions due to increased number of automobiles and industrial sources. d. Increases in demands on other utilities and public services. Short-term Impacts. The following short-term impacts can be expected during construction of the Phase I improvements: 1. Construction of the force main may cause, through the duration of con- struction, adverse effects on aesthetics and human comfort and possible adverse affects on human welfare. Noise caused by jack- hammers used to break pavement before trenching may cause discomfort to persons in the immediate vicinity. Noise generated by the use of other construction equipment, including trucks, may cause moderate discomfort. Open trenches may pose a threat to safety along Jefferson Street. Earthwork may generate dust, possibly causing discomfort and nuisance. Temporary placement of excavated material along the trenches will be aesthetically objectionable. Use of vehicles, engines, and other equipment will add to existing exhaust emissions. 2. Construction of the Buena Vista force main will involve digging of trenches at locations adjacent to both Buena Vista and Agua Hedionda Lagoons. Noise will have a significant temporary effect on the birds in Buena Vista Lagoon and some wash water and run-off will flow down Jefferson Street into the lagoon. 3. Portions of Jefferson Street will be unpassable to traffic for relatively short periods of time during construction of the force main. 4. Temporary increases in emissions of noise and dust, and increases in movements of personnel, material and vehicles in and to the site of the proposed pumping station modification and force main construction will occur during construction. Noise generated during construction will be associated with the use of excavation equipment, and con- struction vehicles. Since there is some distance between each of the Environmental Impact Statement 83 construction sites and residential areas ,activities by the contractor will only minimally affect these areas. Construction activity at night is not anticipated. No significant permanent effects will be in evidence subsequent to con- struction. There will be some short-term inconveniences caused by construction operations, but these are not severe and will be of relatively short duration. Probable Adverse Effects Upon the Environment Which Cannot be Avoided ' The following are adverse environmental impacts which cannot be avoided if the projects are undertaken: 1. There will be a permanent increase in electrical power consumption required at both pumping stations, 22 5 1/Yv under peak load conditions. 2. Gaseous exhaust emissions to the atmosphere from the standby power units at the pumping station site will be permanently increased over existing levels. The increase is due to the larger capacity gas-turbine replacing the reciprocating diesel engine as a standby power source. 3. The added wastewater handling capacity will accommodate future planned population growth. Care should be taken in other areas of planning such as land use and transportation that unsound develop- ment of any area does not occur. 4. Temporary increases in emissions of noise and dust and movements of personnel, material, and vehicles in and to the pumping station areas will occur during construction. 5. Construction and installation of equipment, sewers and other structures will involve temporary transformations in soils and landforms. Mitigation Measures Proposed to Minimize the Environmental Impact The conception of the project is carefully calculated to provide maximum benefit to the surrounding environment. Discussed below are the project's compatibility with future regional management of wastewater, and aspects of the projects which are pertinent to water quality, air quality, visual aesthetics and human comfort, earthquake and flood hazard, and effects on wildlife. Discussion of some construction procedures is also included to illus- trate environmental protection tehcniques. 84 Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations Compatibility with Future Regional Management of Wastewater. The pro- posed projects are compatible with existing and future water quality control plans of the State of California. They are included in the project list adopted by the Regional Water Quality Control Board (RWQCB) for the 73-74 fiscal year. The project conforms well to the regional scheme which has been adopted and listed in the Interim Water Quality Control Plan for the San Diego Basin. Furthermore, the pumping station enlargements were identified in the current CPO "Water Sewerage, and Flood Control Systems Plan and Implementation Program." Con- struction is called for in the period of FY 74-75 to FY 75-76. Water Quality Considerations. The proposed projects will allow compliance with the water quality objectives and discharge requirements for the San Diego Basin, as established by the RWQCB. In addition to the fact that the projects are designed for expansion in phases to meet all discharge requirements until about the year 2000, certain aspects of the projects deserve special mention. Completion of these projects will insure that wastewater is not accidentally discharged into either of the local lagoons in the City of Carlsbad. This will allow the lagoons to be utilized for their best possible use, and to the maximum benefit of both local citizens and visitors. Without these projects, the lagoons could soon become accidental receivers of wastewater and contain excessive nutrients. The self-cleaning process of the lagoons would be reversed, and eutrophication would occur again as it has in the past, bringing odors and un- sightliness to both lagoons. Air injection into the force main is currently being used to minimize hydro- gen sulfide and other wastewater odor emissions from manholes and pumping stations. This technique will continue to be used and the volume of air injected will be roughly proportional to the rate of wastewater flow. Air injection will minimize malodorous emissions from all points. Air Quality Considerations. As mentioned previously, the project is de- signed to accommodate the planned growth of the area with a phased construction program. According to the State Air Implementation Plan, from an air basin-wide view point, this predicted growth will not result in a degradation of air quality below national ambient air quality standards. Gaseous emissions at the pumping stations will consist of combustion products from engine exhaust, and of odors generated by the wastewater. The emission of air pollutants associated with operation of the facilities will not be excessive. The pumps are normally driven by electric motors, while the gas- turbines would only be used for standby power. Odors associated with the waste- water pumping activity will not be detectable outside the boundaries of the pump- ing station. It is not likely that pollution of air with dust will be appreciable in the immediate vicinity of the construction sites. Stipulations in the construction contract will minimize the impact of this problem. Environmental Impact Statement 85 Noise Considerations. Noises generated during construction will be those associated with use of jackhammers, engines and warning devices of construction vehicles and equipment. Far-reaching sounds of percussive action, such as caused by pile drivers or blasting, will not occur. No special provisions for control of vibrations will be warranted since there are no residences or other property that will suffer appreciable reverberations from the equipment and pro- cedures that will be used. Night-time construction of sewers will be prohibited in the construction contract. , Construction Procedures. Certain procedures will be undertaken during construction of the proposed facilities to protect the environment from potential unacceptable adverse impacts that the project might have. Those procedures which are noteworthy to the project are described below. The construction contract will require that the contractor use methods and provide facilities to prevent violations of water quality standards during and after construction. The contract will prohibit use of insecticides, herbicides, or defoliants and will require that the contractor collect any spillages of chemicals, equipment washwater, petroleum derivatives and other potential contaminants of water prior to their entry into surface or subsurface waters of the State. Disposal will be made at a site specified by the engineers for the participating agencies. The construction contract will require the contractor to schedule and conduct work to minimize interference with operation and maintenance of the present waste- water transmission facilities. The contractor will provide whatever temporary facilities are required to maintain continuous pumping station operation, since bypassing of untreated wastewater to surface waters will not be permitted during construction. The construction contract will require that the contractor not contribute to violations of air quality standards during construction, nor otherwise jeopardize visual aesthetics of the air, or human health, comfort and welfare. This pro- vision will be enforced with respect to all construction activities, including spraying for dust control and soil movement. The construction contract will specify that trees and other vegetation identi- fied by the agencies must be unaffected by construction. Replacement of vegetative growth will be fostered at construction sites by seeding and planting of seedlings after completion of construction. Vegetation planted will be chosen to conform with the surrounding environment and the ecological balance and state of suc- cession prevailing among surrounding growths. In some areas ground cover can be re-established within a reasonable time by natural processes, without planting by man. Spoil will be disposed of in a natural depression not affected by water drainage. It will be appropriately shaped after placement to present a smooth and finished appearance. The construction contract will require the contractor to pre- vent accumulation of liter resulting from his work and to clean up and restore the 86 Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations vicinity of the work area to a finished neat appearance and to replace landscaping and pavement. Visual Aesthetics and Human Comfort. Public acceptance of a wastewater pumping station is dependent upon its impact on an individual's aesthetic senses, specifically with respect to its appearance and the odors produced by its process units. In order to present a pleasing appearance, all above-ground structures will be designed to harmonize with the stations' surroundings. Grounds within the confines of the pumping stations will be landscaped, and landscaping materials will be selected for easy care and hardiness in the environment to be encountered at the pumping station sites. To a large measure, odors from a wastewater pumping station can be related to the quality of operation and the adequacy of the design. Odor nuisance with the selected design is not anticipated. Noise of pumping station operation will be caused by minor vehicular traffic, motors , air blowers and emergency generator engines. The inlet of the blowers and the exhaust of the engines will be equipped with silencers, and those areas of the pumping station prone to the generation of noise will be further provided with sound-deadening baffle walls. The detectable noise level at the boundary of the plant will be insignificant in comparison with the noise generated by the traffic at the adjacent Jefferson Street interchange with State Highway 78. The pumping stations will be arranged for convenient access to all areas. In order to simplify operation, provide consistent operational characteristics and eliminate the need for trained operators to supervise the pumping, automated controls will be provided wherever feasible. Ventilation systems for the wet well, into which wastewater discharges from gravity sewers, will be designed for a complete renewal of air not less than every 3 minutes to control the accumulation of fumes, noxious odors and dangerous or toxic gases. Because these areas may contain explosive gasses, all electrical work will be in accordance with require- ments for hazardous locations. Ventilation and lighting systems for all buildings will be designed to provide pleasant surroundings and a functional and attractive working environment • Effects on Wildlife. No wildlife will be physically displaced by any portion of the proposed projects. The exterior construction necessary for both projects involves laying parallel force mains adjacent to existing lines. Consequently, all animals were displaced when the first force mains were constructed in 1965. Furthermore, the Buena Vista force main route will be constructed entirely within Jefferson Street and following proper construction procedures, therefore, the force main installation should not physically interfere with any animal commun- ities. There will be additional construction noises which will be unavoidable in the vicinity of Buena Vista Lagoon caused by installation of the force main under Jefferson Street. Noise observations during weekdays indicate that there is a Environmental Impact Statement 87 significant contribution from Interstate 5 and State Highway 78 to noise in the area. Although construction noise will occur in addition to the continuous free- way din, it will not significantly exceed the maximum noise level which currently exists. Only a small portion of the force main will be installed at any one time, thus staggering the noise loads induced into the area. There will be no signifi- cant noise contribution around Agua Hedionda Lagoon during construction of the improvements to the pumping station. For these reasons, the proposed projects would have no significant or mea- surable long or short-term effects upon the local animal population. Most of the species under consideration have become accustomed to the random noise that is generated around a human community. Earthguake and Flood Hazard Considerations. An earthquake which causes the ground surface to rupture and offset will inevitably destroy any structure located at the point of rupture. Any utility structure outside the zone of rupture, on the other hand, is not likely to suffer extensive damage. A study of the effects of earthquakes on underground structures indicates that there are few reports of ruptured water or sewer lines during any but major earthquakes of catastrophic proportions •1 Even in those tremors, pipeline damage seems to have been confined to those lines which crossed the fault and those lo- cated in filled, or "manmade" ground near the epicenter of the shock. It appears reasonable, then, to assume that the probability of occurrence of serious seismic damage to underground sewers and pumping stations during a major earthquake is remote. The design of the components of the project would be such that the earth- quake hazard will be minimized. More detailed geological and soils investigations will be conducted during the design phases of the project, however, to ensure that the project would not contribute significantly to the adverse impact of an earth- quake. Flood hazard associated with the Buena Vista Pumping Station site is signi- ficant. Although the existing station is situated in the flood plain of Buena Vista Greek and was slightly inundated during the 1969 floods the facility was main- tained in operation. Continued use of this site for a pumping station, however, required extensive protection against additional flooding. Flood control facilities at Buena Vista include an existing dike surrounding the pumping station, which should eliminate the problem of exterior flooding in the future. Agua Hedionda Pumping Station is located high enough to effectively eliminate the possibility of exterior flooding from the adjacent lagoon. Alternatives to the Proposed Action A detailed discussion of available options for Vista Sanitation District and the City of Carlsbad were presented in Chapter 8. Selection of the proposed projects from among the viable alternatives was based on an evaluation of econo- mic, socio-economic and environmental factors. 88 Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations Irreversible and Irretrievable Commitments of Resources Resources that must be committed by construction of the proposed project include land, manpower, and materials including concrete, steel and other common materials of construction. New commitments of resources required by operation of the proposed projects include an incremental increase of approximately 60-90 kilowatts of electrical power, and minor amounts of other materials. These rates of electrical usage are based on average flows of about 5. 5 mgd and 7. 0 mgd anticipated during Phase I operations at Buena Vista and Agua Hedionda Pumping Stations, respectively. Dedication of the pumping station areas to their present use makes it self- evident that irretrievable environmental impacts associated with the construction and operation of wastewater transmission facilities in that location have been deemed acceptable in light of environmental benefits to be derived. The same would apply to the expansions that were foreseen when the pumping stations were first constructed. Irretrievable adverse impacts associated with expansion of the pumping stations would be insignificant in view of present land use. Possible Opposition to the Project Serious consideration has been given to environmental impacts of the pro- posed project. Facilities would be provided in the projects to mitigate all fore- seen significant effects that are subject to control. Continuation of operations at the present locations is desirable in terms of the overall utility needs of the cities of Vista and Carlsbad. Opposition to the projects as described in this environmental impact assessment has not been expressed and is not anticipated. Coordination of Public Views It is intended that the public be informed of the nature of the potential impacts of the proposed projects on the environment. It is acknowledged that members of the public may find shortcomings in this report which could be corrected by their participation in hearing proceedings. The time at which hear- ing proceedings will be undertaken will be advertised in the press and copies of this report will be available for review at public libraries and administrative buildings of the agencies at least 30 days before the hearing. CHAPTER 10 RECOMMEND ED PROJECT 89 The recommended project involves design modifications to the existing Buena Vista and Agua Hedionda pumping stations. Both of these pumping stations are, part of the regional wastewater management system of the Encina Joint Powers. Modifications to the pumping stations will greatly improve reliability as well as provide additional capacity to convey wastewater flows from the Vista Sanitation District and the City of Carlsbad to the Encina WPCF for treatment and disposal. The modifications will alleviate several mechanical problems to insure greater protection against the possibility of system failures and the resulting overflow of wastewater to adjacent lagoons. Buena Vista Pumping Station As discussed in the previous chapter, Plan BV2 was selected as the recom- mended plan. This project will expand the existing pumping station by incorpora- ting modifications into the original design. By means of this project, the ultimate capacity of the facility will be 19 • 4 mgd, while the first phase expansion will provide a capacity of 13 • 0 mgd. Description -Long-Range Plan. Modifications to the existing facility to be undertaken in all construction phases consist of a sequential removal of the existing pumps and installation of larger pumps of higher capacity to serve the area to the period 1995-2000. The finished portion of the existing parallel 16-inch force main will be utilized and completed with a 24-inch diameter force main section, located under Jefferson Street and paralleling the existing 16-inch line prior to connection with the parallel portion of the 16-inch force main located in the bridge over Interstate 5. The wet well will be completely isolated from the remainder of the pumping station and will have an exterior entrance. Extensive modification of the wet well will be undertaken, and the existing pump suction inlet nozzles will be replaced with larger custom built piping. This will signifi- cantly lower suction velocities and prevent wet well vortexing and consequent reductions in pumping capabilities. Any four of the five new pumps will provide enough pumping capacity to handle 19. 4 mgd at the completion of all construction phases and two gas turbine generator sets will provide enough standby power to completely operate the pumping station for three days. A new, high capacity ventilation system will be installed to provide continuous air changes to the station and the wet well. Piping will be rearranged to allow optimum component performance and accessibility for maintenance. Detailed drawings of the proposed modifications in various views can be seen in Fig. 10-1. 90 Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations Initial Construction -Phase IA and IB. The project proposed for initial construction is limited to the Phase I program and will serve the projected needs of the area to about 1983. Phase I of the proposed modifications consists of series installation of the parallel 24-inch force main and pumping station addit- ions. Addition of the parallel force main in Phase IA will increase the existing pumping capacity to 4400 gpm (6 .34 mgd) with two pumps on and 6100 gpm (8. 78 mgd) capacity with all three pumps in operation. Improvements during Phase IB will include installation of two new 10 x 10 x 21 pumps to supplement the existing pumps and extensive modifications to the existing wet well, includ- ing modifications to the suction nozzles of the new pumps. The capacity at this point will be 9000 gpm (13 mgd) with one new pump and all three existing pumps in operation, while a capacity of 9600 gpm (13. 8 mgd) could be realized with all five pumps operating. This capacity corresponds closely with the existing capa- city of the receiving interceptor sewer system in the City of Carlsbad. A single 225 KVv turbine generator will also be installed as a standby power source. Cost Estimate. The total project cost at present price levels for the additional pumping station capacity provided by all construction phases is estim- ated to be $1,151,200, of which $669,400 is required for Phase I modification at present price levels. A breakdown of the estimate by phases and pumping capa- city is given in Table 10-1. The actual cost of Phase I improvements must be escalated, however, to reflect the ENR index prevailing at the mid-point of con- struction. As shown in Table 10-2, the project costs of the parallel 24-inch force main addition and pumping station improvements during Phase I are esti- mated to be $Z29, 000 and $555,000, respectively, at ENR indices of 2400 and 2660. The estimate is based on a 10 percent annual price escalation and in- cludes an allowance for contingencies, contractor's overhead and profit, and engineering. Agua Hedionda Pumping Station As discussed in the previous chapter, Plan AH2 was selected as the recom- mended plan. The existing pumping station will be expanded by incorporating modifications into the original design. By means of this project, the ultimate capacity of the facility will be 31 mgd, while the first stage expansion will pro- vide a capacity of 15. 0 mgd. Description -Long-Range. Modifications to this pumping station will con- sist of a sequential removal of the existing pumps and installation of larger pumps of higher capacity. The existing upper floor will be extended to cover the entire building and the pump motors and motor control center will be relocated on the upper level. The wet well will be completely isolated from the remainder of the pumping station, and will have an exterior entrance. Extensive modifications to the wet well will include replacement of all existing pump suction inlet nozzles with larger custom built piping. The larger nozzles will significantly lower suction inlet velocities and prevent wet well vortexing and consequent reductions in pumping capacity. A parallel 18-inch diameter force main will be installed to lower velocities and provide additional capacity. Any three of the four new pumps NO. 6 PUMP NO. 2-----~ PUMP NO. NO. NO. 5 PUMP NO. 3 -----~ / PUMP NO. 4 PLAN VIEW -LOWER LEVEL /'+------~--------------- -. ♦ " II II II II ,, II • PLAN VIEW -UPPER I I.,. I I I I I I I I ,~1 I ', ~---,.-------+~ \ LEVEL I I I 1-: ,, ,, ,, ,, 11 ,, 1.,/ ~ 1 SECTION fig. 10-1. Proposed Improvements to the Bueno Vista Pumping Station Recommended Project 91 Table 10-1. Estimated Costs for Total lmprovements0 -Buena Vista Pumping Station Cost Item Equipment Installation Construction -Phase IA (6,34 mgd) 24-inch force main 107,500 27,500 Contingencies (10% of equipment cost) 11,000 Contractors overhead and profit 21,900 Total construction cost 167,900 Engineering, contract administration (2 5 %) 42,000 Total cost -Phase IA 209,900 Construction -Phase IB (13.0 mgd) Wet well isolation 9,200 Ventilation system 8,500 4,000 Gas turbine generator(225 KW) 55,000 20,000 Pumps, drives, motors (2) 57,000 21,500 Instrumentation and electrical 28,500 12,000 Wet well modifications 15,000 Valves, fittings and piping 28,000 10,000 Overhead crane 20,000 8,000 Sub-total -· Caoital equipment 222,000 Sub-total -Installation 75,500 Contingencies {10% of equipment cost) 22.000 Sub-total 319,500 Contractors overhead and profit 48,000 Total construction cost 367,500 Engineering, contract administration (25%) 92,000 Total cost -Phase IB 459,500 Construction -Phase II (16. 6 mgd) Pump, drive, motor 28,900 12,000 Electrical 11,000 6,000 Valves, fittings and piping 10,500 7,000 Sub-total -Capital equipment 50,400 Sub-total -Installation 25,000 Contingencies (10% of equipment cost) 5,000 Sub-total 80,400 Contractors overhead and profit 12,000 Total construction cost 92,400 Engineering, contract administration 23,100 Total cost -Phase II 115,500 92 Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations Table 10-1. Estimated Costs for Total lmprovements0 -Buena Vista Pumping Station (Continued) Cost Item Equipment Installation Construction -Phase III (19 • 4 mgd) Pumps, drives, motors 57,800 20,000 Electrical 17,000 10,000 Valves, fittings and piping 21,000 9,000 Gas turbine generator (350 KW) 75,000 28,000 Sub-total -Capital equipment 170,800 Sub-total -Installation 67,000 Contingencies (10% of equipment cost) 17,000 Sub-total 254,800 Contractors overhead and profit 38,200 Total construction cost 293,000 Engineering, contract administration (25%) 73,300 Total cost -Phase III 366,300 Total project costs Phase IA September, 1974 to December, 1975 209,900 Phase IB September, 1974 to February, 1977 459,500 Phase II 1983 115,500 Phase III 1990 366,300 Total cost for all project phases 1,151,200 a Based on an ENR Construction Cost Index of 2200 representing present day costs at the completion of all construction phases will provide enough pumping capacity to handle 31 mgd, and a gas turbine generator set will provide enough standby power to completely operate the pumping station for three days. A new, high capacity ventilation system will be installed to provide continuous air changes to the station and the wet well. Piping will be rearranged to allow optimum com- ponent performance and accessibility for maintenance. Detailed drawings of all of the proposed modifications are shown in Fig. 10-2. Initial Construction -Phase I. The project proposed for intial construction is limited to the Phase I program and will serve the needs of the area to about 1980+ During Phase I, a single 12 x 12 x 21 pump will be installed with its motor e'xposed at ground level. The standby engine will be removed and replaced with a 225 'KVv" turbine generator, located outside the station, while new motor controls will be located inside the existing structure. A new expanded ventilation system will also be installed. The capacity after the completion of Phase I will be 10, 400 gpm (15 • 0 mgd) with the three existing pumps in operation, while a capa- city of 13,500 gpm (19. 8 mgd) could be attained utilizing the new pump and two existing pumps. Recommended Project 93 Table 10-2. Projected Costs of Pho~• I Improvements -Bueno Vista Pumping Station Cost Item Equipment Installation Construction -Phase IA (6. 34 mgd) 24-inch force main 117,300 30,000 Col)tingencies (10% of equipment cost) 12,000 Contractors overhead and profit 23,900 Total construction cost 183,200 Engineering, contract administration (25%) 45,800 Total cost -Phase IA Y 229 ,oooa 7 Construction -Phase IB (13. 0 mgd) Wet well isolation 11,100 Ventilation system 10,300 4,800 Gas turbine generator (225 KW) 66,500 24,200 Pumps, drives, motors (2) 68,900 26,000 Instrumentation and electrical 34,500 14,500 Wet well modifications 18,100 Valves, fittings and piping 33,900 12,100 Overhead crane 24,200 9,700 Sub-total -Capital equipment 267,500 Sub-total -Installation 91,300 Contingencies (10% of equipment cost) 26,800 Sub-total 385,600 Contractors overhead and profit 58,100 Total construction cost 443,700 Engineering, contract administration (25%) 110,900 Total cost -Phase IB I 554, 600b / ~ a Based on ENR Construction Cost Index of 2400 at mid oint of construction eri d se on ENR Construction ost In ex of 2660 at midpoint of construction period "JI 76((000 t Cost Estimate. The total project cost for the additional pumping station capacity provided by all construction phases is estimated to be $757,200, of which $295,000 is required for Phase I modifications at present price levels. A breakdown of the estimate by phases and corresponding pumping capacity is given in Table 10-3. The actual cost of Phase I improvements must be escalated, how- ever, to reflect the ENR index prevailing at the mid-point of construction. As shown in Table 10-4, the project cost of Phase I is estimated to be $393,000 at an ENR index of 2 9 3 0 occurring in 19 7 7 • llf°.D. CA ,tt.S&i1t., 94 Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations Table 10-3. Estimated Costs for Total lmprovements0 -Agua Hedionda Pumping Station Cost ··-Item Capital cost Installation Construction -Phase I (15. 0 mgd) Wet well isolation 2,000 2,000 Control panel relocation 9,000 6,000 Ventilation 5,000 2,000 Gas turbine generator (225 KW) 55,000 20,000 Pump, motor, drive 32,000 16,000 Valves, fittings, piping 13,000 6,000 Engine removal 10,000 Instrumentation and electrical 9,000 6,000 Sub-total -Capital equipment 125,000 Sub-total -Installation 68,000 Contingencies (10% of equipment cost) 12,000 Sub-total 205,000 Contractors overhead and profit 31,000 Total construction cost 236,000 Engineering, contract administration (25%) 59,000 Total cost -Phase I 295,000 Construction -Phase II (23 .3 mgd) Pump, motor, drive 32,000 14,000 Valves, fittings and piping 12,000 5,000 Electrical 7,000 5,000 Sub-total -Capital equipment 51,000 Sub-total -Installation 24,000 Contingencies (10% of equipment cost) 5,000 Sub-total 80,000 Contractors overhead and profit 12,000 Total construction cost 92,000 Engineering, contract administration (25%) 23,000 Total cost -Phase II 115,000 Construction -Phase III (31 ,0 mgd) Force main construction 4,000 2,000 Pumps, motors, drives (2) I 64,000 20,000 Electrical 10,000 4,000 Valves, fittings, piping 15,000 3,000 Gas turbine generator (350 KW) 75,000 28,000 Sub-total -Capital equipment 168,000 Sub-total -Installation 57,000 Contingencies (10% of equipment cost) 16,800 Sub-total 241,800 Recommended Project 95 Table 10-3. Estimated Costs for Total lmprovements0 -Agua Hedionda Pumping Station (Continued) Cost Item Capital cost Installation Contractors overhead and profit 36,000 Total construction cost 277,800 Engineering, contract administration (25%) 69,400 Total cost -Phase III 347,200 Total project costs Phase I July, 1976 to December, 1977 295,000 Phase II 1980 115,000 Phase III 1990 347,200 Total cost for all project phases 757,200 a Based on an ENR Construction Cost Index of 2200 Table 10-4. Projected Costs of Phase I lmprovements0 -Agua Hedionda Pumping Station Cost Item Capital cost Installation Construction -Phase I (15 . 0 mgd) Wet well isolation 3,000 3,000 Control panel relocation 12,000 8,000 Ventilation 7,000 3,000 Gas turbine generator (225 KW) 73,000 26,000 Pump, motor, drive 42,000 21,000 Valves, fittings, piping 17,000 8,000 Engine removal 13,000 Instrumentation and electrical 12,000 8,000 Sub-total -Capital equipment 166,000 Sub-total -Installation 90,000 C ontinge ncie s (10% of equipment cost) 17,000 Sub-total 273,000 Contractors overhead and profit 41,000 Total construction cost 314,000 Engineering, contract administration (25%) 79,000 Total cost -Phase I 393,000 a Based on an ENR Construction Cost Index of 2930 Implementation Schedule Timing on the initial phase of construction is largely dependent upon the present needs of the agencies served by the facilities. Since the PWWF capacity of both pumping stations is already exceeded, it is recommended that wet well 96 Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations modifications commence at the beginning of the dry weather period. Further delay in initiating design and construction could cause significant revisions in planning, as well as additional construction costs. An additional reason for immediate con- struction is caused by the small amount of time that the Buena Vista Pumping Station may be shut down to allow construction of wet well modifications. Limited upstream storage in the sewerage system will permit the pumping station to be inoperable for only a few hours during low flow conditions. Furthermore, increases in wastewater flows from Vista in subsequent years will greatly reduce the amount of time available for construction. Projections of wastewater characteristics and flow were used to predict the timing of future construction phases. It is recognized, however, that urban devel- opment may occur at a faster or slower rate than predicted. The phased construc- tion program for both pumping stations will allow for periodic review of regional population and development growth rates and, accordingly, for adjustment in the timing of future construction. Since construction of the Buena Vista Pumping Station modifications is most critical with respect to capacity, a detailed schedule for undertaking the proposed Phase I modifications on this pumping station has been developed as follows: Submit and Review Design Report and EIR Prepare detailed plans and specifications: a. BV force main b. BV pumping station EIR review and approval Permit from San Diego Coast Regional Commission Advertise for bids and selection of contractors a. BV force main b • BV pumping station Construction a. BV force main b • BV pumping station Authorization received to prepare final plans for AH pumping station August, 1974 to October, 1974 October, 19 7 4 to February, 19 7 5 October, 19 7 4 to April, 19 7 5 October, 1974 to November, 1974 November, 19 7 4 to December, 19 7 4 March, 1975 May, 1975 June, 1975 to December, 1975 September, 1975 to March, 1977 June, 1975 PUMP PUMP NO. 2-----~ PLAN VIEW -LOWER LEVEL I L_ _________ _ PLAN VIEW -UPPER LEVEL NO. 4 NO. 3 GAS -TURBINE GENERATOR SECTION 0 SECTION 0 fig. 10-2. Proposed Improvements to the Agua Hed ionda Pumping Station Recommended Project Prepare detailed plans and speci- fications for AH pumping station Advertise for bids and selection of contractors for AH pumping station Construction of AH pumping station July, 1975toJanuary, 1976 February, 19 76 to March, 19 76 July, 19 76 to December, 19 77 97 Due to the need of each participating agency to accumulate construction funds, Phase I improvements for the Agua Hedionda Pumping Station are deferred since the capacity requirements of Buena Vista Pumping Station are more critical. As shown above, the implementation schedule for Agua Hedionda is similar to the schedule for Buena Vista. Operating and Maintenance Program Upon completion of the proposed pumping station projects wastewater will be directed to the Encina WPCF for treatment and disposal. Pumping stations at Carlsbad will operate continuously and will have the capability of being enlarged to convey wastewater flows projected to occur between the years 1995-2000. The Encina WPCF is operated for the joint system owners by the San Diego County Department of Sanitation and Flood Control. The Department's operating organization includes a plant superinten- Table 10-5. Operating Staff at Encina WPCF dent and supporting operational staff. =================== The personnel classification, pre sent Present SWRCB staff level and qualifying grade levels Personnel staff level grade ------------If-------+-----held by the current staff is shown in Operator 3 (plant superin-Table 10-5. Furthermore, a staff of over tendent) 1 Grade II 10 engineers, technicians and mainten- Operator 2 1 Grade II , , l bl ll f k Operator 1 3 Grades II-N ance men 1s ava1 a e on-ca or wor Senior Sanitary Chemist 1 N/A and/or consultation. Associate Sanitary Chemist 1 N/A Laboratory Assistant 1 N/A Gardner 1 N/A In accordance with the state regu- ---------~---~-----lations1 the Encina WPCF is classified as a Maintenance men (mechanical and electrical) are also available on-call from San Diego County Department of Sanitation and Flood Control. a Class III wastewater treatment plant. These regulations also establish the mini- mum requirements for qualification of persons having direct responsibility for operation of treatment plants. These operator requirements vary depending on the treatment process and design flow. At present the plant superintendent at the Encina WPCF possesses a SWRCB Grade II Wastewater Treatment Plant Operator Certificate, meeting the level of competence required by State regulations . 98 Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations Basin Plan Analysis The proposed project is compatible with water quality control plans of the State of California; it is included in the statewide project list adopted by the State Water Resources Control Board for the 1973-74 fiscal year. The project con- forms well to the regional scheme recommended in the Interim Water Quality Con- trol Plan for the San Diego Basin2 . Regional Land Use Plan Analysis Development of the proposed project entailed coordination with local and County land use planners to ensure that the project was compatible with existing and future land use. Sizing of the pumping stations was based on land use and population data developed by San Diego County and local planning agencies. The San Diego County General Plan for 1990 was used as a general guide for future land use data presented herein. Specific land uses for the more densely populated areas were obtained by referring to the following more detailed plans; (1) Vista General Plan, and (2) City of Carlsbad General Plan. Furthermore, the proposed project is identified in the current CPO "Water, Sewerage And Flood Control Systems Plan and Implementation Program". Construction of these projects is scheduled by CPO to occur during the period of FY 1974-75-to FY 75-76. Bypass Analysis Bypassing of any quantity of wastewater flows to either Buena Vista or Agua Hedionda Lagoon is prohibited by local water quality regulations. Both existing pumping station configurations, however, would discharge wastewater to the adja- cent lagoon if severe internal overloading should occur. As previously mentioned, Buena Vista Pumping Station would be flooded from inside and drain into Buena Vista Creek, and Agua Hedionda Pumping Station would overflow directly into Agua Hed- ionda Lagoon. Proposed modifications to the existing facilities would, upon con- struction, eliminate the bypassing of wastewater to local receiving waters by means of additional pumping and standby capacity. Facilities provided for on-site power generation at the individual pumping stations will make operation of these units independent of outside power during emergencies. Bypassing caused by mechanical failure is minimized by provision of pumping capacity sufficient to handle F'WWF with the largest pump out of service. Each of the participating agencies in the joint system have ordinances pro- hibiting the direct discharge of storm waters to the sanitary sewerage system and new sewers in the system are inspected for infiltration prior to being used. CHAPTER 11 FINANCIAL PIAN As indicated in preceding portions of this report, Vista Sanitation District 99 and the City of Carlsbad propose a project identified as Modifications and En- larg·ement of the Buena Vista and Agua Hedionda Pumping Stations. The proposed project was included in the statewide list adopted by the SWRCB for Federal and State funding during the 1973-74 fiscal year. Subsequent to the initiation of engineering studies, however, the SWRCB adopted a priority list for grant eligibility which eliminated chances of grant funding for the proposed project. The cost of the pumping station improvements, therefore, have to be borne by the local partici- pating agencies. One of the problems common to public works projects of the magnitude con- sidered herein is that of developing an adequate and economical procedure to finance construction and provide funds for operation and maintenance. An engin- eering report can be of assistance in this regard by providing certain basic infor- mation. The purpose of this chapter is primarily to present the projected financial requirements of both Vista Sanitation District and the City of Carlsbad in con- structing the proposed project and to discuss possible sources of revenue. A know- ledge of what sources of revenue may be available to the District and how they may be adapted into an integrated and equitable financial program is useful in forming a basis for future financial planning • METHODS OF FINANCING Two basic methods available to a governmental body for funding the construc- tion of sewerage projects are: (1) payment from current revenue or reserves created from such revenues, and (2) payment with borrowed funds. In the first instance, current revenues and contributions are accumulated until construction can be fin- anced on a pay-as-you-go basis. Borrowed funds, on the other hand, are obtained from the sale of either general obligation bonds, for which the full faith and credit of the issuing agency are pledged, or limited obligation bonds, which comprise special assessment and revenue bonds. Sources of Revenue The financial resources of a City or Sanitation District stem from its ability to levy taxes and to obtain revenue from other sources such as annexation fees, connection fees and service charges. Generally an agency will obtain revenue from a combination of these sources. 100 Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations Ad Valorem Taxes. As provided under State of California codes, a City or Sanitation District is empowered to levy assessments which becomes liens on the land located within its constituted area. Funds thus obtained may be used for payment of bond interest and redemption as well as to defray costs of operation, maintenance and administration. An ad valorem tax, applied to all property within the service area, spreads the cost to lands for which capacity has been provided but is not yet utilized. For this purpose, a low rate is generally acceptable to the taxpayer. The princi- pal objections to an ad valorem tax are that (1) it interferes with financial needs of 6ther governmental functions which must rely primarily on such taxes and (2) it is not equitable with regard to actual use of the facilities. Annexation and Connection Fees. It is common practice for agencies pro- viding sewerage service to charge a fee for the annexation of new property. Such fees are usually distributed on an areal basis and are normally designed both to recover escaped taxes and to provide a portion of the funds required for financing the construction of needed improvements. , In an effort to spread the cost of sewerage improvements as equitably as possible on the basis of proportionate use, most districts and agencies also re- quire payment of a substantial fee upon connection of a residence or other building to the sewer system. This fee is a charge designed to cover reserve trunk and treatment capacity, the cost of which already has been borne by those initially connected to the system and is in addition to any local improvement district assess- ment, lateral sewer inspection charge, or reimbursement for the actual cost of mak- ing the connection. Revenue thus obtained is normally used to provide funds for future construction. Sewerage Service Charges. An agency providing sewerage service has the authority to charge users of its system for the services it renders. Revenue so derived may be used to pay interest and principal charges on either revenue bonds or general obligation bonds. It may be used also to meet administration, operation and maintenance costs or the costs of construction, or both. Revenue from service charges offers the simplest form of direct revenue. Sole dependence on this form of revenue, however, places the entire burden on those having a connection to the system, whereas a substantial portion of the cost has been incurred to provide reserve capacity for residents to be served in the future and for land which will be developed for urban purposes. General Obligation Bonds Because they are back'ed by the total assets of the issuing agency and thus are attractive for investment purposes, general obligation bonds normally carry the most favorable rate of interest. In the absence of other sufficient revenue, however, they must be secured by ad valorem taxes. Financial Plan 101 In California, general obligation bonds issued by cities are not limited in their outstanding total and may be issued for special improvements to a portion of the city as well as for the city as a whole. They are limited to a maximum term of 40 years and a maximum annual interest rate of 7 percent. Approval of the electroate is mandatory and requires a two-thirds majority of the total number of votes cast. Revenue for Administration, Operation and Maintenance The principal benefit of administering, operating and maintaining a sewerage system is derived by the users of the system. For this reason revenue for these purposes is most equitably obtained through the sewerage service charge. ASSESSMENT OF COSTS Determination of the financial responsibility for constructing the improve- ments to the pumping stations will be limited to the Phase I program. The costs of Phase I modifications were determined in Chapter 10 to be $229,000 and. $555,000 for Buena Vista Force Main and Pumping Station, respectively, and $393,000 for Agua Hedionda Pumping Station. Existing Agreements In the Basic Agreement of the Encina Joint Powers entered into by Vista Sanitation District and the City of Carlsbad on July 13, 1961, the ownership rights in each of the pumping stations and force mains were established as shown in Table 11-1 • Table 11-1. Allocation of Ownership and Costs in Pumping Station Facilities Ownership rights Vista Sanitation District Capacity, Capacity, Facility mgd Percent mgd Buena Vista Pumping Station and Force Main Existing 4.6 94.5 4.3 Phase IA and IB 13.0 84.5 11,0 Agua Hedionda Pumping Station Existing 10.4 59.5 6,2 Phase I 19 .8 C 61. 5 12.2 a Have excessive capacity rights (in percent) for projected needs b "Buy-in" costs c Based on operation with one existing pump as standby Cost, dollars Percent a 5.5 651,000 15.5 3,ooob 40.5 242,000 38.5 Carlsbad Capacity mgd 0.3 2.0 4.2 7.6 Cost, dollars 35,000b 133,000 a 151,000 On June 7, 19 73, the two agencies entered into a supplemental agreement which identified the basis by which the engineering costs associated with pro- viding additional capacity would be shared. In Item 6 of the Supplemental Agreement, the costs "shall be shared by Vista and Carlsbad in proportion to their added capacity rights in the project, as determined and set forth in the project report". For purposes of this report, the above cost sharing basis will be followed in allocating total project costs to each agency. 102 Improvement and Enlargement of the Buena Vista and Agua Hedionda Pumping Stations Determination of Cost Sharing Wastewater flow capacity requirements of each agency at each pumping station were identified in Chapter 4. Each participating agency's capital con- tribution will be directly proportional to its incremental increase in PWWF capa- city reservation in each of the joint facilities at the end of the Phase I enlarge- ment as shown in Table 11-1. The total cost of Phase I construction to Vista Sanitation District and City of Carlsbad will be $651,000 and $133,000, respect- ively, for the Buena Vista facilities, while costs to the respective agencies for Agua Hedionda Pumping Station improvements would be $242,000 and $151,000. Furthermore, the original investment in the existing permanent structural facilities must be reallocated to reflect the revised distribution of capacity. Carlsbad requires about 15. 5 percent of the total capacity in the Buena Vista Pumping Station subsequent to Phase I enlargement. Initially, however, Carlsbad possesses only 5 .5 percent of the capacity in both the pumping station and force main. Conversely, Vista Sanitation District requires a 2. 0 percent increase in the capacity rights at Agua Hedionda Pumping Station. To equitably redistribute the capacity rights in the existing facility, the original and subsequent investments must be (1) depreciated with use, and (2) inflated to represent existing value. The present value of the cost of existing facilities is then allocated to each agency on the basis of required capacity. The difference between the present value of the actual investment by each agency and the present value of the required ownership rights must be transferred from one agency to the other in exchange for additional capacity rights. On this basis, therefore, Carlsbad must pay $35,000 to Vista Sanitation District for Buena Vista facilities, while Vista Sanitation District must pay $3,000 to Carlsbad for owner- ship rights in the Agua Hedionda facilities. APPENDICES A References B Environmental Impact Report -Outline and Location of Information APPENDIX A References REFERENCES Chapter 1 1. Brown and Caldwell, Encina Regional Sewerage Survey, November 1971. 2. State of California, Regiona 1 Water Quality Control Board, San Diego Region, Interim Water Quality Control Plan, June 1971. Chapter 3 1. State of California, Department of Water Resources, Groundwater Occurrance and Quality: San Diego Region, Bulletin No. 106-2, June, 1967. 2. Natural Resource Inventory for the County of San Diego, Environmental Development Agency, Section 5, Coa sta 1 Environment. 3. State of California, Air Resources Board, Implementation Plan for Achieving and Maintaining the National Ambient Air Quality Standards, February, 1972. 4. San Diego County Water Authority, Twenty-Sixth Annual Report, 1972. 5. Brown and Caldwell, Consulting Engineers, Encina Regiona 1 Sewerage Survey, November, 1971. 6. Coastal Lagoons of San Diego County, Environmental Task Force, County of San Diego, Summer 1970. 7. Natural Resource Inventory for the County of San Diego, Environmental Development Agency, Section 4, Vegetation and Wildlife. 8. State of California, Regional Water Quality Control Board, San Diego Region, Interim Water Quality Control Plan, June 1971. 9. Atlantis Scientific, Environmental Impact Analysis for the San Elijo Joint Sewerage System, prepared for the Environmental Development Agency, County of San Diego, January 19 7 2. 10. Velz, C.J. and Eich, H.F., HowOldAreOurCities? Civil Engineering, October, 1940. REFERENCES Chapter 4 1. State of California, Department of Water Resources, Residential Unit Water Use Survey, Monterey Hills Tract, Los Angeles County, for the period March 1962 -March 1964, February, 1966. 2. Silva, R., Land Uses and Water Consumption Requirements, Public Works, April, 1959. Chapter 5 1. County of San Diego, Department of Special District Services, Sanitary Engineering Division, Operationa 1 Guide for Buena Vis ta Pumping Station, August 19 65. 2. County of San Diego, Department of Special District Services, Sanitary Engineering Di vision, Operationa 1 Guide for Agua Hedionda Pumping Station, August 19 65. Chapter 6 1. State of California, State Water Resources Control Board, Water Quality Control Plan for Ocean Waters of California, July 6, 1972. Chapter 9 1. U.S. Department of Commerce, Coast and Geodetic Survey, Earthquake History of the United States, Part 2, No. 41-1, 1960. Chapter 10 1. State of California, State Water Resources Control Board, Rules and Regulations for Classification of Sewage Treatment Plants and Levels of Competence for Operation, April 1971. 2. State of California, Regional Water Quality Control Board, San Diego Region, Interim Water Quality Control Plan, June 1971. APPENDIX B Environmental Impact Report -Out I ine and Location of Information APPENDIX B ENVIRONMENTAL IMPACT REPORT - OUTLINE AND LOCATION OF INFORMATION INT,RODUCTION -Chapter 1 DESCRIPTION OF PROJECT -Chapter 10 DESCRIPTION OF ENVIRONMENTAL SETTING -Chapter 3 ENVIRONMENTAL IMPACT The Environmental Impact of the Proposed Action -Chapter 9, p. 81 Any Adverse Environmental Effects Which Cannot Be Avoided if the Proposal is Implemented -Chapter 9, p. 83 Mitigation Measures Proposed to Minimize the Impact -Chapter 9, p. 83 Alternatives to the Proposed Action -Chapter 8 The Relationship Between Local Short-Term Use of Man's Environment and the Maintenance and Enhancement of Long-Term Productivity - Chapter 8, p. 68; Chapter 9, p. 83, 84 and 95 Any Irreversible Environmental Changes Which Would Be Involved in the Proposed Action Should It Be Implemented -Chapter 9, p. 88 The Growth-Inducing Impact of the Proposed Action -Chapter 8, p. 78 ORGANIZATIONS AND PERSONS CONSULTED - This environmental impact report was prepared for Vista Sanitation District and the City of Carlsbad by Brown and Caldwell, an environmental engineering firm. The following Federal, State and local agencies, and other organizations were consulted during the preparation of this report: 1. California Regional Water Quality Control Board, San Diego Region 2. City of Vista, Public Works Department 3. City of Vista Planning Department 4. City of Carlsbad, Public Works Department 5. City of Carlsbad, Planning Department 6. City of Oceanside, Public Works Department 7. Comprehensive Planning Organization 8. California Coast Regional Commission, San Diego Region 9. San Diego Gas and Electric Company 10. State of California Air Resources Board 11. State of California, Department of Water Resources, Southern Section 12. U.S. Environmental Protection Agency, Region IX, San Francisco, California 13. Vista Irrigation District 14. San Diego County Water Authority 15. San Diego County, Department of Sanitation and Flood Control 16. San Diego County, Environmental Development Agency WATER QUALITY ASPECTS -Chapter 9, p. 84 -Chapter 10, p. 98