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HomeMy WebLinkAbout1972-12-05; City Council; 959; Enlargement of Encina Water Pollution ControlTHpQlTY OF CARLSBAD, CALIFORlf** pW V ~ fr-~ 3 Agenda Bill Mo. tf*5"tf Date Dec. 5, 1972 Referred To: Subject:Submitted By: Enlargement of Encina Water Pollution Control Public Works Director Facility - Environmental Impact Statement of the Matter On August 2, 1972, the plans and specifications for the Phase II expansion were approved by the Council. At that time, the Council was not asked to take specific .action on the Environmental Impact Statement which had been submitted to the Federal Environmental Protection Agency. The statement has since been approved by EPA and the grant offer is expected shortly. Although the Council has informally considered the important environmental aspects of this project several times in the past, you should take formal action to approve the statement as submitted to EPA. The statement is attached as Exhibit (A). Supplemental information is attached as Exhibit (B). Exhibit (A) Environmental Impact Statement (B) Brown & Caldwell letter to State Water Resources Control Board dated June 2, 1972. Staff Recommendations Adopt a motion approving the EIS as submitted, AS NO Date: Dprpmher 5. 1972 City Manager's Recommendation Concur. Counci1'Action 12-5-72 'It was agreed that the Environmental Impact Statement be approved as presented for the enlargement of the Encjna Water PollutionControl Facility. — 2 — r~ o CHAPTER 3 ENVIRONMENTAL IMPACT STATEMENT The Encina Water Pollution Control Facility (WPCF) is a regional wastewater treatment plant located on the coast about 20 miles north of metropolitan San Diego and the plant presently serves the following four local sewerage agencies: the Vista Sanitation District, City of Carlsbad, Buena Sanitation District, and San Marcos County Water District. The project involves increasing the capacity of the Encina WPCF from 6.75 mgd to 9.75 mgd and extending the existing ocean outfall 2,500 feet further offshore to a discharge depth of about 150 feet and will provide the additional capacity required for connection of the Leucadia County Water District and the Encinitas Sanitary District or only for Leucadia. It is in accor<|- ance with recommendations of the 1960 North Coastal San Diego Sewerage Survey and the Interim Water Quality Management Plan of the San Diego Basin as adopted by the California Regional Water Quality Control Board, San Diego Region. Probable Impact of the Project on the Environment Enlarging the Encina WPCF will have a definite beneficial impact on the environment. Providing treatment and wastewater disposal capacity for Leucadia and Encinitas at this regional plant will enable these two agencies to abandon their existing treatment plants. As mentioned in Chapter 1, these plants are presently discharging treated effluent on the land through wastewater reclamation. Both the Leucadia and Encinitas plants are located in essentially rural areas that are presently being urbanized. As these areas become urbanized sewage flows at the plants increase and there is less land available for the disposal of treated effluent. The project does involve construction on a site which is already occupied by a wastewater treatment plant and thus does not change the character of the land except to add new structures of a similar type and height to the facility. The impact on the environment due to construction activities at the treatment plant site will be negible because the site is located almost one mile from the nearest resi- dential area. There will be some limited short-term impact on local traffic. There will also be a short-term impact on the environment due to the ex- tension of the outfall which will be limited to an area generally located 1.5 miles offshore and approximately 500 feet on either side of the 2,500 foot extension of the outfall. Construction activities in this area will probably include a work barge for laying the pipe, several other barges for hauling pipe sections and rock ballast and a smaller boat for transporting workers to and from the site. Personnel 'BROWN AND CALDWELL CONSULTING ENGINEERS' o o Environmental Impact Statement 28 involved in the construction of the outfall will travel to and return from the site by boat probably from the harbor at Oceanside. These construction activities offshore will cause minor obstruction to the boating traffic in this area and will cause no impact to Carlsbad State Beach. There will be no increase in the noise level from the treatment facility as a result of this project, except during the construction phase. Major construction at the plant will include one covered primary sedimentation tank and one heated, gas mixed sludge digester. These additional facilities will be designed to be as odor-free as possible. The project will provide wastewater treatment and disposal capacity for two existing sewerage agencies and as such, the areas to be served by increasing the plant capacity are already sewered or zoned for development. The facility does improve prospects for population increases which are planned for and anticipated in the county. Probable Adverse Environmental Affects The probable adverse environmental affect which cannot be avoided is the short-term affect that will result due to the construction activities. It is antici- pated that these activities, however, will cause no permanent adverse changes in the character of the land, water, air or noise level. The treatment plant site is already used for wastewater treatment. It is located between the San Diego Freeway and the Atchison, Topeka and Santa Fe railroad tracks and the area is planned for industrial use. The only other possible adverse affect is that which the discharge might have on the marine environment. The occurrence of this, however, is considered to be very unlikely, based on the results of the numerous studies discussed in Chapter 1. Mitigation Measures Proposed to Minimize the Impact The following specifications and operating procedures will minimize the short-term adverse impact due to the construction activities: (1) The contractor will provide reasonable means to prevent a nuisance occurring because of dust from areas under construction. Such means will include watering and sweeping, and in cases of extreme nuisance, light oiling of the affected surfaces. (2) Throughout the performance of the work the contractor will construct and maintain suitable and safe crossings over trenches and such detours that are necessary for safe passage of public and private traffic. (3) Existing structures will be maintained or restored to match the appear- ance of existing improvements as nearly as possible. 'BROWN AND CALDWELL CONSULTING ENGINEERS' c Environmental Impact Statement 29 (4) In regard to the offshore work on the outfall the contractor will comply with regulations of all legally constituted authorities having jurisdiction over the work in navigable waters. This will include providing and maintaining all the navigational aids required by these regulations. There have been four detailed marine bilogical investigations offshore of the Encina WPCF; two of these investigations were conducted prior to the discharge of wastewaters and the other two were conducted subsequent to the discharge. The investigations are summarized in Chapter 1 of this report. As a result of these investigations it was determined that the wastewater effluent from the existing outfall was not adversely affecting the marine environment. Also as part of the Regional Board's discharge requirements quarterly surveys are conducted of the offshore receiving waters, including the bottom sediments. Results of these surveys have indicated that the water quality requirements for these waters have continuously been achieved. To guard against the possibility of the discharge from the Encina WPCF in the future causing an adverse effect on the marine environment, an ongoing comprehensive monitoring program is being conducted. This program is required by the Regional Water Quality Control Board, and will be continued indefinitely. Monthly reports, which are transmitted to the Board include analysis of the treated effluent discharged to the ocean and quarterly reports on the receiving water quality characteristics. Alternatives to the Proposed Project The alternative to this project would be that the Leucadia County Water District and Encinitas Sanitary District continue treating and disposing their own wastewaters. In order to do this, their treatment plant capacity would have to be increased. If inland disposal of this treated effluent (wastewater reclama- tion) were to be continued, a long-term contract for the reclaimed water would be required. An analysis of the wastewater reclamation potential throughout the study area indicates that this potential does not exist. Therefore, these agencies would have to construct their own ocean outfalls to dispose of their wastes for a long-term solution to their problems. This alternative is not only more costly than the project proposed, but would not be in accordance with the regional concepts presented in the Interim Water Quality Management Plan. The alternative of having no project at all would cause a detrimental effect on the environment for the Leucadia County Water District and Encinitas Sanitary District in that these agencies would have to (1) discharge improperly treated wastewater and (2) curtail building construction in their respective service areas. Short-Term Use Versus Long-Term Productivity The site of the treatment facility is in an area planned for industrial use and is not distinctive in any way except that it is now being utilized for wastewater treatment. Other than occupying space at the treatment plant site, the project will have no known cummulative or long-term detrimental effects on the environment. "BROWN AND CALDWELL CONSULTING ENGINEERS' c Environmental Impact Statement 30 -~a Irreversible and Irretrievable Commitments of Resources The project will involve constructing new wastewater treatment structures on a site that is already occupied by a wastewater treatment plant. This will not be in conflict with the future environment planned for this area. Objections to the Project At present there is no known organized objection to the project. 'BROWN AND CALDWELL CONSULTING ENGINEERS" BROWN AND CALDWELL. CONSULTING ENGINEERS SAN FRANCISCO ALHAMdPA VENTURA WATERWORKS • DRAINAGE WASTE WATER TREATMENT RATE STUDIES•VALUATIONS CHEMICALS BACTERIOLOGICAL LABORATORIES K. W. BROWN • 1901-1961 D. H. CALDWELL F. J. KERSNAH J. C. LUTHIN J. T. NORGAARD R. F. WILCOX CE 6287 CE 6799 CE 5697 CE 6821 CE 8274 UN 06 1972 June 2, 1972 State Water Resources Control Board Division of Water Quality Control Room 1140, Resources Building 1416 Ninth Street Sacramento, California 95814 Attention: Mr. Donald Hodge Subject: Clean Water Grant Application- Vista Sanitation District Gentlemen: In accordance \vith your letter of May 11, 1972, we have made a comprehensive reply to each of the questions raised by the Federal Environmental Protection Agency (EPA) concerning the Environmental Impact Statement for the subject project. This letter transmits oar reply to these questions. The migitation measures proposed in the Environmental Impact Statement to minimize tfhe short-term adverse impact due to construction activities have been incorporated into the contract specifications for this project. As indicated in the Project Report, the treatment plant is designed to be constructed . in phases. The proposed project is the Phase 2 enlargement of the plant. Phase 3 enlargement is scheduled as a FY 1975 Project and it will include'an enlargement of the plant's capacity and an increase in the degree of wastewater treatment. The in- crease in the degree of treatment will have to meet future revised discharge require- ments that will be based on a statewide water quality control plan for ocean waters that is presently being formulated by the State Water Resources Control Board. In reference to the remarks regarding industrial dischargers connected to the'Encina system, the report entitled Financial Plan and Revenue Program, Encina Water Pollution Control Facility, 1972 Enlargement and Ocean Outfall Extension, dated April, 1972, COPY 25 !V\! s? i i i i it\iHi M ' ' L.^L—!_.L..'L.. iL t.'-.'ll i y^f i ff \ i- i —^* I 2v Z Z %\^% m o C/J ft* •H.H BROWK AND CALDWELL 100 EAST HUNTINGTON DRIVE ALHAMERA CALIF. 91801 (213) 283-3108 State Water Resources Control Board -2- June 2, 1972 describes industrial sewerage rates for each of the aaencies indicating how the industrial dischargers will repay costs properly allocable to them. If there is any need for further information, please do not hesitate to contact us, Yours very truly, BROWN AND CALDWELL . r / J. Lynn Hartford Project Engineer cc: Mr. Charles B. Oldsen CRWQCB, San Diego Region JLH: me encl. BROWN AND CALDWELL 100 EAST HUNTINGTON DRIVE ALHAMBRA CALIF. 9180.1 (213) 289-6135 /•**, 1. 1970 Census = "42,000 Design year 1975 = 83,000 Is this growth due to sewered areas tying into the Encina plant or does it reflect new growth? The sewered population growth shown above occurs as a result of the connections of Leucadia County Water District and Encinitas Sanitary District to the Encina WPCF, increases in percent of connected population, as well as by anticipated growth. Including both Leucadia and Encinitas, the 1970 census of the area to be served by the Encina WPCF was 57,700 people, of which approximately 10 percent were estimated to.be using individual disposal systems. For purposes of design of the proposed project, it has been assumed that all of the population in 1975 will be connected to the Encina WPCF. The population of the Encina area increased by about 39 percent during the past decade, while all of San Diego County increased by about 31 percent. It is anticipated that the rate of population growth in the Encina sewerage service area to the year 1975.will continue to be much higher than the pro- jected rate of about 15 percent for San Diego County. During the last two years alone, the number of connections to the joint system have increased by more than 20 percent. 2. The major item of cost in this project is the outfall extension, why do we need it? The existing ocean outfall is to be extended 2,260 feet further offshore. At this distance offshore the average depth of the diffuser section is 150 feet below MLLW. Discharging the treated wastewater at this depth will produce an effluent field which will remain submerged below the water surface under all but the most adverse winter conditions. This will enable the effluent from the treatment plant to meet the discharge requirements without effluent chlcrina- tion except during the most adverse winter conditions which normally occur for only a few days each year. 3. Describe the discharge coming out of the outfall. Percent of BOD removed, toxic materials, currents of the area, thermoclines - plumes that may be visible, etc. The waste discharge from the Encina WPCF has consistently been in conformance with the discharge requirements outlined in the California Regional Water Quality Control Board, San Diego Region, Resolution 63-Rl, including Addenda Numbers 1 and 2. The following table compares recent Encina WPCF effluent quality data with these effluent discharge requirements. The analyses compiled for this table are those that are submitted monthly to the Regional Water Quality Control Board and are based on an effluent sample that is automatically collected over a 24-hour period and composited with respect to flow. ' .-2- Discharge Effluent quality ' requirements, Concentration, Removal, Effluent constituents mg/1- mg/1 % Biochemical oxygen demand annual mean None 93 36.7 Suspended solids annual mean 125 89 53.1 maximum 150 122 - Hexane soluble material annual mean 30 15 maximum . 45 , 27 - Gross heavy metals' (total con- . • centration of cadmium, hexava- lent chromium, copper, lead, nickel and zinc) , annual mean 2.0 1.20 maximum 5.0 1.50 - As described in our answer to question 2, the ocean outfall is being f extended to provide a submerged effluent field. The proposed extension terminates in a multiport diffuser approximately 800 feet long. The creation of a waste plume approximately 800 feet long on its main axis will not re- present an undesirable visible effect because the effluent field will remain submerged and thus will not be visible. Hydrographic and physical oceanographic studies were conducted during the period January 11 to 13, 1972, to provide additional data for the design of the proposed ocean outfall extension for the Encina Joint Sewerage Agency. A copy of this report is enclosed to describe the physical oceanographic characteristics in the proposed discharge area. Physical oceanographic studies consisted of vertical profiles of water temperature, salinity, pH, dissolved oxygen and current speed and direction at hourly intervals for a 25-hour period. 4. Why is abandonment of reclamation treatment plants a desirable move? • Isn't water a valuable commodity in Encina? Water is, indeed, a valuable and scarce commodity in the Encina area as indicated by the predominant use of imported Colorado River water as the water supply. To conserve water in the area, both Leucadia and Encinitas have provided waste water effluent for irrigation use in the past. Use of the wastewater effluent from both plants will be discontinued, however, for a variety of reasons. For about eight years, effluent from the Leucadia County Water District plant was used for irrigation of the golf course at Rancho La Costa. Use of this reclaimed wastewater was discontinued when Rancho La Costa indicated that they no longer wanted to use District effluent for irrigation purposes because of the following reasons: (1) poor mineral quality — 3— effluent (total dissolved solids concentration of 1500 mg/1), and (2) poor soil characteristics. The low percolation rates of the clay soil in the area have prevented effective leaching of the mineral constituents. Because of the severity of the problem, all of the effluent from Leucadia is presently being conveyed to the Encina WPCF on an interim contractual basis. The - Encina facility is presently receiving about 0.50 mgd of the 0.75 mgd committment made to Leucadia by the Joint Powers. All of the wastewater effluent from the Encinitas Sanitary District WPCF is presently reclaimed by irrigation of about 900 acres of a large floral farm. The reclaimed effluent is used by the floral farm at neither cost nor : revenue to the District. Use of the treatment plant and wastewater reclamation will be discontinued when the District connects to the Encina WPCF. The principal reason for this is that the District's treatment plant is located in an area that is presently experiencing urban development and the plant has had frequent odor problems. Furthermore, the owner of the farm will not give a long-term committment to the District for effluent use. Inceasing residential development of land surrounding the ranch has also made use of the odorous effluent less than desirable. • # At present, there are no significant alternative uses for reclaimed water from the above treatment plants and any future demands must be evaluated considering the particular quality standards to be met, project costs involved and their relationship to the benefits derived. A complete evaluation of the future use of reclaimed water is made in Chapter 5 of the Encina Regional Sewerage Survey. To what extent will this project encourage urbanization of the area? Has the State Air Implementation Plan pointed out any air quality problems in the area? tt^ Unlike the establishment of a facility intended solely to develop a re- source, such as a dam, or to convert resources, such as a factory, the pro- • vision of wastewater treatment and disposal facilities only indirectly may of itself cause expansion in economic activity or growth in population. Such facilities are provided to protect the environment from certain adverse effects resulting from economic activity and existing and future populations. The system is so designed as to implement the planned, projected growth in population or economic activity. The treatment plant has been designed to be constructed in phases, so that flexibility is available in planning for future capacity increases. It should be'recognized that urban development of the Encina area may occur at a faster or slower rate than projected. The affect of such a change will be to advance or delay the date when construction is initiated and when following phases are undertaken. In any case, later phases of .the proposed construction program should be periodically reviewed and adjusted, as required. The proposed project will not cause any displace- ment of population. -4- The State Air Implementation Plan has pointed out relatively high concentrations of oxidants in the City of Oceanside. The national ambient air quality standard for oxidants is 0.08 ppm as a 1-hour average, while the maximum 1-hour level of 0.40 ppm in the basin was recorded at Oceanside. The proposed project will not contribute to the air pollution problem. 6. Will there by any problem of effluent coming back onto Carlsbad State Beach or any other recreational area? By extending the outfall to a water depth of 150 feet and providing a multiport diffuser section, discharge of the effluent will be diluted with the surrounding sea water on the order of 200 to 300 parts of sea water to 1 part of effluent. When dilutions of this magnitude occur with the colder more dense bottom water in the density stratified seawater mass offshore from the Encina WPCF, the resulting effluent field will remain submerged beneath the relatively less dense surface water. This will occur at a depth where the density of the effluent field is equal to that of the surrounding sea water. V/hen the sea water mass has little or no density stratification, the effluent field will continue to rise until it reaches the surface. This will occur during only the most severe winter conditions. During the previously mentioned physical oceanographic studies in January , 1972, it was determined that ocean current direction was predominantly longshore. The current averaged about 0.14 knots at the surface and decreased to about 0.11, 0.08, and 0.04'knots at depths of 50, 100, and 125 feet, respectively. Based on the anticipated effluent field characteristics, and measured current speed and direction, it may be concluded that there will be no public health or aesthetic problem caused by effluent coming back onto Carlsbad State Beach or any other recreational area. 7. Give a complete breakdown of population figures. Discuss population grov.rth and the proposed project in terms of air quality, groundwater problems, salt water intrusion, availability of adequate water supply. . Past and projected populations are presented in the following table for both drainage basins and service areas of agencies located within the area which may eventually be served by the Encina WPCF. Population projections were based on the logistic curve method and consisted of (1) estimating the saturation population, (2) plotting on a logistic grid the best estimate of the past population as a percent of saturation and (3) extending the plotted line to intersect certain dates. Drainage Basin Political Agency Buena Vista Vista Occanslds Carlsbad Agua Hedionda Vista Carlsbad Buena Oceanslde Encinas Carlsbad Batlqultos Carlsbad San Marcos Leucadla Cottonwood Enclnltas Study area Agency totals Vista Oceanslde Carlsbad Buena San Marcos Leucadia Enclnltas 1950 10.000 6.500 0 0 4.500 2.500 2.500 23.500 I960 22.900 4,010 980 980 9,860 4.790 4,790 47,500 12.900 S.900 11.400 3,500 3,900 4,950 4.790 1970 34,400 12,900 1,160 1,160 14,100 6,500 6,500 69,100 18/600 11,400 15,700 4,500 7,100 5.400 6,510 - 1980 61,200 40,100 12,300 8,800 21,200 1.720 •9,900 7,800 1,780 2,100 2,100 '30,100 3,900 15.100 11,100 10,400 10.400 125,000 41,820 14,080 24.700 7.800 15,100 11,100 10.400 1990 88.200 57,600 17,900 12,700 35,900 2,800 16,800 13,300 3,000 3,800 3,800 56.100 7.200 28,200 20.700 15,000 15,000 199.000 60,400 20,900 40",500 13,300 28,200 20,700 15,000 2000 111,000 72,500 22,400 16,100 59,800 4,800 27,800 22, 100 5.100 6,500 6,500 92,700 11,900 46.600 34.100 19.100 19.100 289,000 77,300 27,500 62,300 22,100 46,600 34.100 19,100 2010 130,000 84,500 26,300 18,600 90.000 7.300 41,900 33.300 7.500 10.000 10.000 142.000 18.200 71.500 52.300 22.000 22,000 394.000 91,800 33,700 89.400 33.300 71.500 52.300 22,000 Since most future industrial developments are expected to be "light" in nature, it is anticipated that air quality problems will result primarily from an increase in number of motor vehicles. According to the State Air Implemen- tation Plan, in the past two decades there has been a substantial migration from the "inner city" to the suburbs. As a result of the increase in the area of residential communities, the number of motor vehicle miles traveled has increased at a greater rate than the population. In 1970 there were more than 725,000 motor vehicles registered in the air basin enclosing San Diego County, with an increase of 250,000 vehicles expected by 1980. No air pollution problems are expected to occur as a result of the proposed project. Due to the existing poor quality, little or no use is made of groundwater in the Encina area. The existing groundwater in most cases, is unsuitable for either irrigation or domestic use and no groundwater is distributed by any of the local water purveyors. The proposed project will not cause greater use of the poor quality groundwater and thus, salt water intrusion or any other /* -6- groundwater problems will not be created or increased. Increased population will, of course, cause a greater demand for water. The water supply for the study area is principally Colorado River water obtained from the Metropolitan Water District through the San Diego County Water Authority. Vista Irrigation District obtains a supplemental supply of water from Lake Henshaw in quantities dependent on rainfall and the resulting runoff during the winter months. The San Diego County Water Quality is planning to adequately meet increased water demands by utilizing Northern California water, which is expected to reach San Diego County in 1974 to supplement the Colorado River supply. Water supplied to the consumer in 1974, and thereafter, will no doubt be a blend of Colorado River water and northern California water. 8. Are there any flooding problems at the proposed site. Will expansion tend to increase these flood problems? The Encina WPCF is not located on the flood plain of a major watershed and therefore, is not subject to major flooding. When the plant was con- structed, a trapezoidal flood control channel (52 foot bottom width, 76 foot top width and 6 foot deep) was provided to accommodate the storm waters from a highway culvert under- Interstate 5 located east of the site. The f channel .discharges to an arch culvert under the Atchison, Topeka and Santa Fe railroad embankment west of the site. Since the plant began operating in 1965 stormwater runoff in the channel has been contained within its banks. This includes the storms that occurred during January and February 1969. A preliminary hydraulic analysis of this flood control channel by the San Diego County Department of Sanitation and Flood Control indicates that a 100 year flood flow could not be discharged through the arch culvert under the railroad embankment without surcharging. A complete investigation of the flood hazard resulting from a 100 year flood and the improvements that would be required to protect the Encina WPCF will be conducted. The study will include evaluation of the effect's of urbanization of the watershed. Improvements needed will be included in the Phase 3 Enlargement project of the Encina WPCF, which is scheduled for FY 1974-75. Possible flood damages to the treatment plant are not anticipated to be severe because flow through the plant is by gravity and there are no influent or effluent pumping facilities. 9. The type of development that is expected should be discussed. If the area is to be developed industrially then the character of the wastewater may change and be detrimental to marine environs. The following table presents the areas of existing and planned future land use classifications: -7- Planned maximum Existing, development, Classification acres acres Residential 7,550 52,501 Commercial 448 1,569 Industrial 75 2,463 Although the percent increase of industrial land is more than 4.5 times greater than residential development, the character of the waste- water is not anticipated to change. In the future, it is expected that relatively "dry" industries, or light water users will predominate in the study area. In addition, emphasis placed on source control programs, anticipated more restrictive discharge requirements in the future and emphasis given to in-house industrial water reclamation are expected to prevent increases in wastewater constituents which v/ill be detrimental to marine environs. Burroughs Corporation, for example, has recently installed a reclamation system which has reduced its water requirements from about 500,000 gpd to 225,000 gpd, while eliminating excessive concentrations of copper from the waste discharge. Further flow volume reductions are also expected. 10. Under objections, the word "organized" tends to imply that there may- be unorganized objection - please clarify. The statement in the Environmental Impact Statement wrongly implies that there was unorganized objection to the project. There is no organized or unorganized objection to the project. A recent bond election in Encinitas passed by a wide margin. Voters in Leucadia, however, defeated their bond issue to finance the proposed project by a 20 vote margin. Opposition to the bond election was not specifically due to the proposed project, but probably to reasons which include: (1) a built-in "no" vote, (2) only a 31 percent turnout by registered voters, (3) the large number of retired citizens in the area, and (4) apprehension to the anticipated increase in taxes.