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HomeMy WebLinkAboutDI 92-03; Carlsbad Master Drainage Plan; Discussion Item (DI)STAFF REPORT DATE: TO: FROM: SUBJECT: I. JULY 1, 1992 PLANNING COMMISSION ENGINEERING DEPARTMENT GG&" DI 92-3 - MASTER DRAINAGE AND STORM WATER OUAlsly MANAGEMENT PLAN - An informational report on the evolution and content of the City's new Master Drainage and Storm Water Quality Management Plan. RECOMMENDATION This is an informational report and no action is being requested. Therefore, no resolutions are attached and no recommendation is being made. Since many conditions contained in discretionary projects involve drainage facilities and storm water quality measures, the rationale behind these Engineering Department conditions is being presented. This document was presented to the City Council in May of 1992 and will return to Council in August for adoption. 11. PROJECT DESCRIPTION AND BACKGROUND In February of 1988, the Carlsbad City Council approved a contract with Fraser Engineering Inc. and Cooper Engineering Associates to update the 1980 Master Drainage Plan. 1. 2. 3. 4. 5. 6. The purpose of the- Mast& Drainage Plan revision-was to: Reassess the storm drainage facility needs of the City and to update the 1980 Master Drainage Plan. Incorporate the drainage facility needs of the southern portion of the City, which was formally included in the County's Zone 1 Flood Control District. Establish drainage facility costs, analyze the viability of existing planned local drainage (PLD) fee areas, recommend changes to existing PLD fee areas, establish new PLD fee areas for the southern City area, allocate costs in accord with the State Map Act and AB 1600 requirements and establish new PLD area fees. Provide new Topographic mapping of the entire City at two foot contour intervals on printed mylar sheets and in digital format compatible with the City's new Geographic Information System (GIs). Field review existing facilities for conformity with file plans and make recommendations on facility maintenance needs. Review the siltation and water quality requirements of the City and make recommendations for additional measures to protect our sensitive riparian waterways and lagoons. MASTER DRAINAGE AN, STORM WATER QUALITY MANAC .AENT PLAN JULY 1, 1992 PAGE 2 During the preparation of the updated Master Drainage Plan document, the regional Water Quality Control Board mandated that the City comply with federal storm water quality regulations as a co-permittee on a National Pollutant Discharge Elimination System (NPDES) permit. The mandate forced a fundamental shift in the focus of the Master Drainage Plan from a program of purely flood control to a program of flood control and water quality enhancement. The major elements of the Storm Water Quality Management Program include the implementation of a storm water monitoring and testing program, an illicit connection and illegal discharge detection program, and a program of Best Management Practices (BMP). The concept of Best management Practices is to essentially do everything that is reasonable and economically feasible to reduce the inflow and transport of urban pollutants into and through the storm drain system. Typically, the BMP's include the construction of pollutant control devices, sediment and siltation controls, street sweeping, storm water facility maintenance, public education, hazardous waste management, recycling and other source reduction controls and programs. The recommendations in the 'Master Drainage Plan document can be grouped into two categories, those relating to fee exactions and those which relate to the Storm Water Quality Management Program. A summary of the recommendations is included in the Executive Summary, attached to the staff report. The full Master Drainage Plan document includes the Master Drainage and Storm Water Quality Management Plan together with Appendix documents "c" - "L",- on file in the Engineering Department. The appendix documents provide greater detail on future facility sizing and cost estimates, and Federal Emergency Management Agency (FEMA) reviews of the major drainage basins and drainage calculations. Iv. ENVIRONMENTAL REVIEW Since this document is a planning and financing tool and does not propose site specific development, and all subsequent improvements will undergo subsequent environmental review, the PlannincDirector has determined that no adverse environmental impacts will result from this document and has, therefore, issued a Negative Declaration on April 30, 1992. ATTACHMENTS 1. Executive Summary for the Master Drainage and Storm Water Quality Management Plan. MASTER DRAINAGE STORM WAmR QUALITY MANAGEMENT PLAN AND' EXECUTIVE SUMMARY A. Goals and Objectives This 1992 Master Drainage and Storm Water Quality Management Plan was commissioned by City Council in February of 1988. The purpose of the plan was to: 1. Reassess the storm drainage facility needs of the City and to update the 1980 Master Drainage Pian. 2. Incorporate the drainage facility needs of the southern part of the City which were formerly included in the County's Zone'i Flood Control District. 3. Establish drainage facility costs, analyze viability ofexistingpianned local drainage (PLD) fee areas, recommend changes to existing PLD fee areas, establish new PLD fee areas for the southern city area, allocate costs in accord with State Map Act and AB 1600 requirements and establish new PLD area fees. 4. Provide new topographic mapping of the entire City at two foot contour intervals on printed mylar sheets and in digital format compatible with our new Geographic Information System (GIS) on computer. 5. Field review existing facilities for conformity with file plans and make recommendations on facility maintenance needs. 6. Review the siltation and water quality requirements ofthe City and make recommendations for additional measuresib protect our sensitive riparian waterways and lagoons. Over the course of preparing the Master Plan, the Federal Government implemented new regulations which mandated strict water quality control requirements. These new water quality regulations signifi- cantly altered the focus of the Master Drainage Plan. Whereas previous master drainage plan studies focused on storm water flood control measures, the new regulations shifted the focus to preservation and enhancement of storm water quality. This shift resulted in a significant re-evaluation of our previous Planned Local Drainage area fee concept. As a result, the numerous localized PLD fee areas were ccmbined into four large PLD fee areas which coincide with the four drainage basins within the City. This reflects the Federal Government emphasis on preserving and protecting the water quality of receiv'ing waters and not just of a few localized basins. In light of this new focus the title of this report was changed from Master Drainaee Plan to _Masternagement Plan. 19'72 Carlsbod Master Oramage and Executlve Summary Storm Water Quality Management Plan Page 1 B. Background The Master Drainage and Storm Water Quality Management Plan, hereinafter called Master Plan, includes all drainage areas within the incorporated boundary of the City of Carlsbad covering approximately 39 square miles. The Master Plan addresses only those facilities which provide the backbone system to the City's storm water management infrastructure. Generally these consist of storm drainage pipes with a diameter of thirty inches or larger together with concrete and rock lined channels, permanent sedimen- tatiodpollutant control basins and other larger miscellaneous facilities. The existing and recommended future drainage facilities are shown on the 1" = 400' maps on file with the City Engineer and the 1" = 1000' maps which accompany this document. Each proposed facility has a letter designation which begins with the letter A, B, C, or D corresponding with one of the four drainage basins in the City.The basin designations were assignedconsecutively starting from the North and moving South as follows: 'A' for Buena Vista Lagoon drainage basin; 'B' for Agua Hedionda Lagoon drainage basin; 'C' for Encinas Creek drainage basin; and, 'D' for Batiquitos Lagoon drainage basin. A total of 43.2 million dollars in recommended drainage improvements have been identified within this Master Plan report. These future facilities are anticipated to be fully funded through the Planned Local Drainage Area (PLDA) fees recommended within this report with the exception of facility BB which is funded through SANDAG Transnet funds. The PLDA fees recommended in the 1980 Master Drainage Plan were levied only upon developments which proposed a subdivision of land. Those fees were collected at the time ofthe approval of the final map. Pursuant to Section 66483 of the State Map Act fees may be levied upon development only insofar as they are fairly apportioned within the fee area on the basis of benefits conferred or on the need for such facilities by the proposed subdivision and development of other property within such fee area. Since some of the recommended facilities serve previously developed areas, their cost could not be fully recouped through the 1980 Master Drainage Plan PLDA fees. This method of assessment placed the full burden of funding needed facilities on the subdivider and allowed non subdivision developers to escape any obligation to pay their fair share of needed drainage facilities. This method of fee collection has resulted in a shortfall of funds required to build the recommended facilities and thereby delayed construction or necessitated use of alternate funding sources primarily from General Fund revenues. The Master Plan report recommends that PLDA fees be levied against all new developments within the City. It further recommends that PLDA feesbe levied against redevelopment projec tsandremodel building permits. For building remodels the PLDA fee will be assessedwhenever the building footprint is increased by 50% or greater. Suchdevelopment projects can be found to derive benefit from the construction of needed drainage facilities for the control of storm water floodingor the presetvation and enhancement of the quality of storm water entering the receiving waters of the City. Authority for the levying of PLDA feeesonnonsubdivideddevelopmentsiscontainedwithintheprovisionsofAB 1600(Chapter5toDivision 1 of Title 7 of the Government Code). All such fees would be paid at the time of building permit issuance including PLDA fees forsubdivisions. ConstructionofPLDA facilitieswouldcontinue tobesecuredprior to final map approval. Executive Summary Page 2 1942 Carlsbad Master Drainage and Storm Water Quality Management Plan As noted in the preceding section, this report recommends elimination of the existing PLD Areas and creation of four new PLD Areas coinciding with the four drainage basins which empty into the Pacific Ocean. This recommendation is based upon several reasons as fo~~ows: 1. Master drainage facilities provide benefit to the City beyond the benefit provided to property owners in any one sub-basin. Most of the Master Plan facilities are needed to protect circulation element roads used by all residents and emergency services. Also Master Plan facilities reduce the potential €or the spread of water borne disease which improves the overall health of the community. 2. Improvingwaterquality within the lagoons provides a general benefit to all Carlsbad residents. New federal regulations require the City to improve water quality within the City’s lagoons and tributary creeks. This must be accomplished by balancing the water quality levels of each OC the subbasins throughout the overall lagoon basin. Therefore, advanced construction or increased facilities may be needed in one basin to make up for deficiencies in another due to a lack of available land or environmental constraints. 3. Fewer basins are easier to administrate and will provide the City greater flexibility in generating funds necessary to construct needed facilities in a timely manner. The Master Plan report also recommends a change in the manner in which fees are computed for various land use types. The existing PLDA fees are computed based upon property acreage regardless of land use. Low density residentially zoned property is charged the same fee on an acreage basis as high density residential, industrial or commercially zoned property. However, the stormwater runoffrate for different land uses are significantly different from one another. Therefore, this report recommends adoption of a varied rate structure in line with average runoff coefficients widely accepted within the Engineering profession. This will result in higher fees for high density residential, commercial and industrial projects inrecognitionofthegreaterstormwatercontributionmadebythesetypeuses. WithintheCentralBusiness District, this fee structure will help generate the funds required to construct badly needed facilities in the downtown area. An analysis ofthe Land Use maps ofthe City and the aerial photography prepared for this report indicates approximately 11,800 acres of developable land remain in the City exclusive of General Plan designated open space. Based upon a review of past records, this report projects 20% of the existing developed properties in the City will remodel or redevelop prior to build out, resultingin approximately 14,000 acres of under-developed property in the City. Dividing the estimated facility costs by the sum of the undeveloped andun6r-developed acreage withineachofthe PlannedLocal Drainage(PLD) Areas yields the proposed fee as indicated below. C. Recommendations The following is a summary of the recommendations made in this Mastet Plan report: 1. Adopt this report titled 1992 Master Drainage and Storm Water Quality Management Plan prepared in April of 1992 in replacement for the previous Master Drainage Plan prepared in June of 1980. 1992 Carlsbad Master Dramage and Storm Water Quality Management Plan Executive Summary Page 3 2. Consolidate the existing thirteen Planned Local Drainage fee areas together with the former Zone 1 Flood Control District into four new Planned Local Drainage Fee Areas coinciding with the four major drainage basins in the City as shown on Figure 4-2 on page 32. 3. Make findings that there are no surplus funds in the existing Planned Local Drainage Area accounts and transfer the current fund account balances into the corresponding account €or the new Planned Local Drainage Fee Area. 4. Make findings that the future drainage facilities identified in the Master Plan report are required for the proper development of the City, that the facility costs included in the report are fair and accurate, andthattheproposedfeeshavebeenfairlyapportionedeitheronthebasisofbenefitsconferredonproperty proposed for development or on the need for such facilities created by the proposed development and the development of other property within the Planned Local Drainage Fee Area. 5. Adopt the following fees for the four proposed Planned Local Drainage Areas: I 11 Fee Der Gross Acre ~ Low Runoff Areas High Runoff Areas A $4,014 $6,569 B $3,321 $5,435 C $1,924 $3,140 D $1,679 $2,747 6. Expand the Planned Local Drainage Area Fee structure to require imposition of the fee to all non subdivision developments including commercial, industrial and residential remodels which increase the building footprint a minimum of50% over the existingstructure. Require payment ofthe new fees at time o€ building permit issuance for those developments. 7. Revise Chapters 20.09 and 18.40 of the Carlsbad Municipal Code to effect the changes as proposed in recommendations 1 to 6 listed above. 8. Adopt the sediment and water quality policies included within the report and continue with the implementation of the water quality control program as required pursuant to the National Pollutant Discharge Elimination System permit requirements. 9. Accept the recommendations of this Master Plan report on facility maintenance needs as presented in Chapter 7. Executive Summary 1992 Carlsbad Master Dralnage and Page 4 Storm Water Quality Management Plan