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(continued) Regional Board Resolution No. R8-2003-0039, adopted on April 4, 2003 by the Santa Ana Regional Water Quality Control Board, modified the regulatory provisions of the Water Quality Control Plan [Basin Plan] for the Santa Ana Region by establishing a TMDL for chlorpyrifos in Upper Newport Bay and diazinon and chlorpyrifos in San Diego Creek.
The amendment addresses water quality impairment due to aquatic toxicity caused by the presence of diazinon and chlorpyrifos in runoff to San Diego Creek and Upper Newport Bay. The amendment establishes load and wasteload allocations for San Diego Creek as listed in Table 1.
Table 1: Load and Wasteload Allocations for San Diego Creek


Diazinon (ng/L) Chlorpyrifos (ng/L)
Acute Chronic Acute Chronic
72 45 18 12.6


The amendment establishes load and wasteload allocations for Upper Newport Bay as listed in Table 2. These apply to chlorpyrifos only.
Table 2: Chlorpyrifos Load and Wasteload Allocations for Upper Newport Bay


Acute (ng/L) Chronic (ng/L)
18 8.1

The amendment includes an implementation plan that specifies completion of the following four tasks by stakeholders in the watershed and by the Regional Board:
(1) Revision of WDR and NPDES discharge permits to include the TMDL allocations;
(2) Implementation of monitoring program by the stakeholders in the watershed for diazinon and chlorpyrifos;
(3) Development of a pesticide runoff management plan by the Regional Board and the stakeholders in the watershed;
(4) Special Studies: the Regional Board will lead studies into the significance of chlorpyrifos atmospheric deposition for Upper Newport Bay and the adequacy of the freshwater allocations for San Diego Creek to protect Upper Newport Bay.




s 3978. Summary of Regulatory Provisions -Basin Plan Amendment Revising the Total Dissolved Solids and Nitrate-Nitrogen Management Plan for the Santa Ana Region. Regional Board Resolution No. R8-2004-0001.
This Basin Plan amendment establishes revised boundaries for groundwater management zones (formerly termed groundwater "subbasins") throughout the Santa Ana Regional Water Quality Control Board. For each of the new management zones, this amendment identifies existing and potential beneficial use designations, and total dissolved solids (TDS) and nitrate-nitrogen water quality objectives based on historical water quality ( "antidegradation" objectives). For certain management zones, this amendment establishes a second set of TDS and nitrate-nitrogen objectives. This second, less stringent set of objectives is based on the finding that water quality consistent with "maximum benefit to the people of the State" will be maintained (the "maximum benefit" objectives), provided that specific water and wastewater projects and programs are implemented. These project and program commitments are delineated in the revised Implementation Plan in the Basin Plan amendment (see below). The "maximum benefit" objectives apply unless the Regional Board finds that the maximum benefit project and program commitments are not being implemented and that the finding of maximum benefit cannot continue to be made. In that case, the "antidegradation" objectives would apply. To address this situation, the amendment specifies that mitigation for TDS and nitrate-nitrogen discharges in excess of discharge limitations based on the antidegradation objectives will be required. The amendment also revises the narrative water quality objectives for chloride, TDS, hardness, sodium, and sulfate applicable to groundwater.
The Basin Plan amendment establishes revised reach boundaries and revised numeric TDS and nitrate-nitrogen water quality objectives for the following surface water bodies: San Timoteo Creek, Chino Creek and Temescal Creek. For San Timoteo Creek, Reach 1A, the groundwater recharge designated use is deleted. No other changes to the beneficial use designations for these surface waters are included in the amendment.
The amendment establishes the Prado Basin Management Zone as a surface water feature. Beneficial uses and surface water quality objectives already established for the major tributary streams in the Prado Basin Management Zone apply for regulatory purposes.
This Basin Plan amendment incorporates revisions to the TDS and Nitrogen Implementation Plan, including the following provisions: revised wasteload allocations for Publicly Owned Treatment Works discharges of nitrogen and TDS to the Santa Ana River and tributaries; revised findings regarding nitrogen and TDS assimilative capacity in the new groundwater management zones; findings regarding nitrogen loss coefficients and their implementation in waste discharge requirements; special considerations for salt management of subsurface disposal system discharges; and monitoring program requirements.
For the agencies and dischargers that are implementing the "maximum benefit" TDS and nitrate-nitrogen objectives, the amendment specifies compliance dates for the implementation of certain projects and programs. The amendment also includes requirements for implementing salt reduction programs when management zone TDS and/or nitrate-nitrogen reach specified concentration trigger points. Finally, with regard to the implementation of the "maximum benefit" objectives, the amendment specifies that if the Regional Board determines that the agencies/dischargers have not complied with the specified requirements for implementation of projects/programs, the Regional Board, at a duly noticed public meeting, would make the determination that the lowering of water quality is not of "maximum benefit" to the people of the State and by default, the TDS and nitrate-nitrogen historical "antidegradation" objectives would apply. The Basin Plan amendment specifies that in this situation, the Regional Board will require mitigation for TDS and nitrate-nitrogen discharges in excess of waste discharge limitations based on the antidegradation objectives.




s 3979. Establish Nutrient Total Maximum Daily Loads (TMDLs) for Lake Elsinore and Canyon Lake in the Water Quality Control Plan (Basin Plan) for the Santa Ana Region.
On December 20, 2004, the Santa Ana Regional Water Quality Control Board adopted Resolution No. R8-2004-0037 to amend Chapter 5 of the Basin Plan to incorporate a nutrient TMDL for the control of nitrogen and phosphorus as factors contributing to the excessive algae growth and low dissolved oxygen in Lake Elsinore and Canyon Lake. The TMDL is intended to achieve compliance with existing Basin Plan water quality objectives to prevent excessive algae growth and low dissolved oxygen. The Basin Plan amendment specifies final numeric targets for total phosphorus and total nitrogen for both Lake Elsinore and Canyon Lake and also specifies interim and final numeric targets for chlorophyll a and dissolved oxygen for both lakes. Monitoring these parameters will provide a method of tracking improvements in water quality resulting from reduction in the loading of nitrogen and phosphorus.
The Basin Plan amendment specifies final TMDL wasteload allocations for point source discharges and load allocations for nonpoint source discharges for total nitrogen and total phosphorus for both Lake Elsinore and Canyon Lake. Finally, the Basin Plan amendment specifies an implementation plan for nutrient reduction in both lakes, which includes compliance schedules to meet interim numeric targets as soon as possible, but not later than 2015, and the final numeric targets by 2020, as well as a monitoring program to track progress toward compliance.
The amendment includes a brief description of the Lake Elsinore/San Jacinto watershed and the existing conditions contributing to water quality eutrophication problems. Lake Elsinore and Canyon Lake nutrient TMDL numeric targets, load capacity (nutrient TMDLs), wasteload allocations, load allocations, implementation tasks, and compliance dates, margin of safety, plus seasonal variations/critical conditions are discussed.




s 3979.1. Basin Plan Amendment Establishing Total Maximum Daily Loads for Bacterial Indicators in the Middle Santa Ana River Watershed.
The Basin Plan amendment modifies the regulatory provisions of the Water Quality Control Plan for the Santa Ana Region by establishing Total Maximum Daily Loads (TMDLs) for bacterial indicators discharged to impaired water bodies in the Middle Santa Ana River watershed, including the Santa Ana River, Reach 3; Chino Creek, Reaches 1 and 2; Mill Creek (Prado Area); Cucamonga Creek (Valley Reach); and Prado Park Lake. The TMDLs address impairment due to bacterial indicators in the Middle Santa Ana River watershed in a prioritized phased approach. Compliance with objectives to protect water contact recreation are to be achieved no later than December 31, 2015 during the dry season and no later than December 31, 2025 during the wet season. Density-based allocations are assigned for urban discharges, agricultural discharges, and natural or open space discharges. These allocations are expected to be implemented through requirements imposed by the Santa Ana Regional Water Quality Control Board in waste discharge requirements and/or conditional waivers of waste discharge requirements. The TMDLs will be re-evaluated and revised, if appropriate, based on monitoring results and relevant studies required by the TMDL implementation plan. These studies include source evaluation and characterization, watershed-wide water quality monitoring, water contact recreation beneficial use assessments, and alternative bacterial indicator evaluations. Based on the results of these investigations, plans for achieving the TMDLs are to be developed by the stakeholders. Revision of the TMDLs would occur through the Basin Plan amendment process.




s 3980. Escondido Hydrologic Subarea, Amendment.
This amendment to the Comprehensive Water Quality Control Plan for the San Diego Region (Basin Plan) relaxes the ground water quality objectives for total dissolved solids (TDS) from 750 milligrams per liter (mg/l) to 1,000 mg/l and for sulfate from 300 mg/l to 400 mg/l in the Escondido Hydrologic Subarea (HSA) (HSA 4.62).




s 3981. Total Dissolved Solids and Boron Groundwater Quality Objectives for the Pauba and Wolf Hydrologic Subareas.
Resolution No. 94-09 of the California Water Quality Control Board, San Diego Region, "A Resolution Adopting Amendments to the Comprehensive Water Quality Control Plan for the San Diego Region, Portions of the Pauba (2.51) and Wolf (2.52) Hydrologic Subareas", relaxed the ground water quality objectives for total dissolved solids and boron in the downstream portions of Pauba (2.51) and Wolf (2.52) Hydrologic Subareas to 750 mg/l for total dissolved solids and 0.75 mg/l for boron.




s 3982. Beneficial Uses and Ground Water Quality Objectives.
The following are changes to the Comprehensive Water Quality Control Plan for the San Diego Basin (Basin Plan): (1) Subdivided the Laguna Hydrologic Area (HA) (HA 901.10), Mission Viejo HA (HA 901.20), and San Clemente HA (HA 901.30) into hydrologic subareas (HSAs), (2) Relaxed ground water quality objectives for total dissolved solids (TDS) and boron in the San Joaquin Hills HSA (HSA 901.11), (3) Relaxed ground water quality objectives for TDS, nitrate, and boron in the Laguna Beach HSA (HSA 901.12), (4) Established more stringent ground water quality objectives for TDS, chloride, sulfate, and boron and designated the municipal and agricultural beneficial uses in the Aliso Creek HSA (HSA 901.13), (5) Established ground water quality objectives for TDS, chloride, sulfate, percent sodium, nitrate, iron, manganese, methylene blue active substances (MBAS), boron, turbidity, color, and fluoride and designated the agricultural beneficial uses in the Dana Point HSA (HSA 901.13), (6) Relaxed ground water quality objectives for TDS, chloride, sulfate, and boron in the Oso Creek HSA (HSA 901.21), Middle Trabuco HSA (HSA 901.23), Gobernadora HSA (HSA 901.24), Middle San Juan Creek HSA (HSA 901.26), Lower San Juan Creek HSA (HSA 901.27), and Ortega HSA (HSA 901.28), (7) Relaxed ground water quality objectives for TDS, chloride, sulfate, and boron in the Prima Desheca HSA (HSA 901.31), and (8) Established ground water quality objectives for TDS, chlorides, sulfate, percent sodium, nitrate, iron, manganese, MBAS, boron, odor, turbidity, color, and fluoride in the Segunda Desheca HSA (HSA 901.32).




s 3983. Revised Water Quality Control Plan for the San Diego Region.
The revised Water Quality Control Plan (Basin Plan) for the San Diego Region, as adopted September 10, 1994, by the San Diego Regional Water Quality Control Board, per Resolution No. 94-10 changes the regulatory provisions of the previous Basin Plan and its amendments as follows:
(a) Beneficial Use Categories and Definitions: Add definitions for "Aquaculture," "Estuarine Habitat" and "Marine Habitat." Revise beneficial use category definitions previously incorporated: Municipal and Domestic Supply" (MUN); Agricultural Supply", "Industrial Process Supply," "Ground Water Recharge," "Freshwater Replenishment," "Navigation", "Contract Water Recreation," "Non-contact Water Recreation," "Cold Freshwater Habitat," "Wildlife Habitat," "Preservation of Biological Habitats of Special Significance," "Rare, Threatened, and Endangered Species," "Migration of Aquatic Organisms," "Spawning, Reproduction, and/or Early Development," and "Shellfish Harvesting."
(b) Water Body Type Definitions: Add definitions for "inland surface waters", "ground water", and "coastal waters" (including ocean waters, enclosed bays, and estuaries).
(c) Inland Surface Waters, enclosed bays and estuaries, coastal lagoons, and ground waters: (1) Revise coliform concentration objective for waters designated for shellfish harvesting (SHELL); (2) Revise water quality objective for biostimulatory substances; (3) Amend numerical objective for boron; (4) Add narrative objective for natural color of fish; (5) Revise water quality objectives for inorganic chemicals for waters designated MUN; (6) Revise water quality objectives for chemical constituents for waters designated MUN; (7) Add maximum contaminant level numeric objective for toluene for waters designated MUN; (8) Add narrative objective for taste and odor of shellfish or other water resources used for human consumption; (9) Add numeric water quality objectives for toxic pollutants; (10) Add numeric objective for trihalomethanes in waters designated as MUN;
(d) Discharge Prohibitions: (1) Add principles for issuing or reviewing general waste discharge permits; (2) Add prohibition for discharge of waste to waters of the state; (3) Add prohibition for discharge of waste to land; (4) Add prohibition for discharge of pollutants or dredge and fill material to waters of the United States; (5) Amend prohibition for discharge of treated or untreated waste to water bodies designated for MUN use; (6) Amend prohibition for discharge of waste to inland surface waters; (7) Amend prohibition for discharge of waste resulting in flow, ponding, or surfacing on lands not under control of the discharger; (8) Amend prohibition for dumping, deposition, or discharge of waste directly into waters of the state; (9) Add prohibition for any discharge to a storm water conveyance not composed entirely of "stormwater"; (10) Amend prohibition for unauthorized discharge of treated or untreated sewage to waters of the state; (11) Add prohibition for discharge of industrial wastes to conventional septic tank/subsurface disposal systems; (12) Add prohibition for discharge of any radiological, chemical, or biological warfare agent; (13) Amend prohibition for discharge of earthen materials from any activity which results in deleterious bottom deposits, turbidity, or discoloration in waters of the state, (14) Add prohibition for discharge of treated or untreated sewage from vessels to Oceanside Harbor, and Dana Point Harbor; and (16) Revise prohibition for discharge of treated and untreated sewage to San Diego Bay.
(e) Water reclamation: (1) Add master requirements for suppliers or distributors of reclaimed water; (2) Add criteria for an exception to biostimulatory substances water quality objective for discharges to coastal water lagoons from pilot water reclamation projects; (3) Add alternative method of showing compliance with biostimulatory substances water quality objectives for inland surface waters downstream of lakes or reservoirs used for municipal water supply; (4) Revise the methodology for determining reclaimed water effluent limits; (5) Add policy regarding consideration of water Reclamation as an alternative to ocean disposal; (6) Add requirements for reclaimed water storage.
(f) Enforcement Actions: (1) Add criteria for selection of the appropriate enforcement action in response to an incident of noncompliance; (2) Add provision on enforcement actions against operators of Navy vessels.
(g) Add policy for regulation of individual domestic subsurface disposal systems, community sewerage systems, and alternative systems.
(h) Add provisions on testing to determine alternative for disposal of dredged material.
(i) Add policy for cleanup and abatement of contaminated soil and ground water.




s 3984. Total Dissolved Solids Ground Water Quality Objective for the Poway (6.2) Hydrologic Area.
Regional Board Resolution No. 94-139, adopted on October 13, 1994, by the San Diego Regional Water Quality Control Board, modified the regulatory provisions of the Water Quality Control Plan (Basin Plan) for the San Diego Basin by relaxing the ground water quality objective for total dissolved solids from 750 milligrams per liter (mg/l) to 1,000 mg/l in the Poway (6.2) Hydrologic Area.




s 3985. Total Dissolved Solids Ground Water Quality Objective for the Moosa (903.13) and Valley Center (903.14) Hydrologic Subareas.
Regional Board Resolution No. 95-48, adopted on May 16, 1995, by the San Diego Regional Water Quality Control Board, modified the regulatory provisions of the Water Quality Control Plan (Basin Plan) for the San Diego Region by relaxing the ground water quality objective for total dissolved solids in the alluvial aquifer from 800 milligrams per liter (mg/l) to 1,200 mg/l in the Moosa Hydrologic Subarea (HSA) (HSA 903.13) and from 800 mg/l to 1,100 mg/l in the Valley Center HSA (HSA 903.14).




s 3986. Suspension of Enforcement of Effluent Limitations for Water Reclamation Projects Due to Water Supply Considerations.
Regional Board Resolution No. 95-95, adopted on October 12, 1995, by the San Diego Regional Water Quality Control Board (SDRWQCB), modified the regulatory provisions of the Water Quality Control Plan (Basin Plan) for the San Diego Region by establishing conditions whereby the SDRWQCB may authorize the Executive Officer to suspend formal enforcement of effluent limitations for water reclamation projects due to water supply considerations.




s 3987. Exception to the Prohibition of Discharges of Recycled Wastewater to Surface Water Bodies Used for Municipal Water Supply.
Regional Board Resolution No. 96-30, adopted on May 9, 1996, by the San Diego Regional Water Quality Control Board (SDRWQCB), modified the regulatory provisions of the Water Quality Control Plan for the San Diego Region by establishing conditions whereby the SDRWQCB may grant an exception to the prohibition against the discharge of recycled water to lakes or reservoirs used for municipal water supply, or to their inland surface water tributaries.




s 3988. Revision of Beneficial Use Designations for Spawning/Reproduction, and/or Early Development and Cold Freshwater Habitat.
Regional Board Resolution No. 97-04 adopted on March 12, 1997 by the San Diego Regional Water Quality Control Board, modified the regulatory provisions of the Water Quality Control Plan for the San Diego Region by: (1) revising the beneficial use definition for "Spawning, Reproduction, and/or Early Development (SPWN)", (2) designating the SPWN beneficial use in 76 water body segments, (3) designating the "Cold Freshwater Habitat (COLD)" beneficial use in 55 water body segments, and (4) deleting the COLD beneficial use designation from 68 water body segments.



s 3989. Incorporating a Waste Discharge Requirement Waiver Policy for Certain Specific Types of Discharges.
The Policy waives waste discharge requirements for waste discharges if the Regional Board has determined that they are not against the public interest, and if they adhere to the stated mandated conditions. For each specific type of discharge, it was determined that it would not be against the public interest under one or more of the following circumstances: 1) the type of discharge is effectively regulated by other public agencies; 2) the type of discharge does not adversely affect the quality or the beneficial uses of the waters of the State; or 3) the type of discharge is not readily amenable to regulation through adoption of waste discharge requirements, but warrants Regional Board oversight to ensure compliance with the mandated conditions.
Each type of discharge included in the Policy is classified into one of two categories based on the degree of potential threat to water quality and/or beneficial uses of affected water bodies. For Category 1 waivers, waste discharge requirements for a specific discharge shall be considered waived only after enrollment in accord with procedures established by the Regional Board. The Regional Board will determine compliance with the Category 1 waiver conditions using a program that includes on-site inspections and/or review of the records of the public agencies that regulate these discharges. For Category 2 waivers, enrollment is not necessary. The Regional Board will assess compliance with Category 2 waiver conditions by means of surveys or other indirect methods.




s 3989.1. Total Maximum Daily Load (TMDL) For Diazinon in the Chollas Creek Watershed, San Diego County.
The TMDL addresses toxicity in Chollas Creek caused by the pesticide diazinon. The concentration-based numeric targets and TMDL for diazinon were set equal to the California Department of Fish and Game freshwater Water Quality Criteria for diazinon. The acute Water Quality Criterion of 0.08mg/L protects aquatic life from short-term exposure to diazinon, while the chronic criterion of 0.05mg/L protects aquatic life from long-term diazinon exposure. The concentration-based wasteload and load allocations of this TMDL were assigned equally to all diazinon discharge sources in the Chollas Creek Watershed. All allocations were set at 90 percent of the numeric targets resulting in a diazinon allocation equal to 0.072mg/L under acute exposure conditions (one-hour average) and a diazinon allocation of 0.045mg/L under chronic exposure conditions (four-day average). Frequency of allowed exceedances are set at once every three years on the average. These allocations include an explicit 10 percent margin of safety to account for uncertainties in the TMDL analysis and represent approximately a 90 percent reduction from current loads.
The responsible parties are the Cities of San Diego, Lemon Grove, and La Mesa, the San Diego Unified Port District, the County of San Diego, and the California Department of Transportation. These entities are responsible for implementation of the TMDL and for reduction of their diazinon discharges. The Regional Board will revise the San Diego Municipal Separate Storm Sewer System Permit to make it consistent with the wasteload and load allocation part of this TMDL. Compliance with numeric limitations for diazinon will be required in accordance with a phased schedule of compliance.




s 3989.2. Total Maximum Daily Load for Dissolved Copper in Shelter Island Yacht Basin.
Resolution No. R9-2005-0019, adopted on February 9, 2005 by the San Diego Regional Water Quality Control Board (San Diego Water Board), modified the regulatory provisions of the Water Quality Control Plan for the San Diego Basin by establishing a Total Maximum Daily Load (TMDL) for Dissolved Copper in Shelter Island Yacht Basin (SIYB), San Diego Bay.
The TMDL addresses toxicity in SIYB caused primarily by copper-based antifouling paints. The numeric targets were set equal to water quality criteria for dissolved copper as set forth by the U.S. Environmental Protection Agency in the California Toxics Rule to protect aquatic life from acute and chronic toxicity. The numeric target for dissolved copper is 3.1 micrograms/liter (mg/L) for continuous or chronic exposure (4-day average) and 4.8 mg/L (1-hour average) for maximum or acute exposures, not to be exceeded more than once every three years.
The TMDL was calculated to be 567 kilograms/year of dissolved copper, amounting to a 76 percent reduction in current loading from copper-based antifouling paints. Most of the load reduction will be required from passive leaching, as well as to a lesser extent from underwater hull cleaning of copper-based antifouling paints.
The dischargers responsible for meeting the copper reductions and allocations are the San Diego Unified Port District, marina owners and operators at SIYB, boat owners at SIYB, underwater hull cleaners at SIYB, and the City of San Diego.
In order to implement the TMDLs, the San Diego Water Board will (1) coordinate with governmental agencies having legal authority over the use of copper-based antifouling paints, which are registered pesticides; (2) regulate the discharge of copper to SIYB waters through the issuance of Waste Discharge Requirements (WDRs), Waivers of WDRs, and/or adoption of Waste Discharge Prohibitions; and (3) amend Order No. 2001-01, "Waste Discharge Requirements for Discharges of Urban Runoff from the Municipal Separate Storm Sewer Systems" to require that discharges of copper into SIYB waters not increase via the City of San Diego's municipal separate storm sewer system from existing loadings. Compliance with the allocations will be required over a 17-year staged compliance schedule. The first stage consists of an initial 2-year orientation period during which no copper load reductions are required. The subsequent 15 year reduction period is comprised of three stages during which incremental copper load reductions are required as shown below.
Table 1. Interim Loading Targets for Attainment of the TMDL


Estimated Interim
Percent Reduction Reduction to Target Loading
Time from Current be Attained by (kg/year of
Stage Period Estimated Loading End of Year dissolved Cu)
Stage 1 Years 1-2 0% N/A N/A
Stage 2 Years 2-7 10% 7 1,900
Stage 3 Years 7-12 40% 12 1,300
Stage 4 Years 12-17 76% 17 567






s 3989.3. Total Maximum Daily Load for Total Nitrogen and Total Phosphorus in the Rainbow Creek Watershed.
Regional Board Resolution No. R9-2005-0036, adopted on February 9, 2005 by the San Diego Regional Water Quality Control Board, modified the regulatory provisions of the Water Quality Control Plan for the San Diego Region by (1) adding a footnote to Chapter 2 (Beneficial Uses) referencing Rainbow Creek's listing on the Clean Water Act Section 303(d) list, (2) adding text to Chapter 3 (Water Quality Objectives) referencing the 303(d) listing of Rainbow Creek and adoption of the TMDLs implementation plans in Chapter 4 (Implementation), and (3) adding text to Chapter 4 establishing total nitrogen and total phosphorus total maximum daily loads (TMDLs) for Rainbow Creek Watershed.
The TMDLs address impairment due to excess nutrients being discharged to the creek from land uses, including agricultural and residential uses, highway runoff, and contaminated groundwater. The numeric targets limit concentrations of nitrate to protect drinking water resources, and total nitrogen and total phosphorus to prevent the development of excessive algae that can lead to eutrophic conditions in Rainbow Creek. Compliance with objectives to protect municipal supply, water contact and non-water contact recreation, and aquatic and wildlife beneficial uses is to be achieved no later than 16 years after U.S. Environmental Protection Agency approval of the TMDLs. Load allocations are assigned for land uses, septic tank disposal systems, and air deposition. Waste load allocations are assigned for highway runoff and unidentified point sources. Reductions will be phased over the compliance period. Implementation includes investigations of groundwater contamination, water quality monitoring, and implementation of best management practices to control runoff. Additional regulatory enforcement options are to be used if necessary. The total nitrogen and total phosphorus TMDLs contain a five percent (5%) explicit margin of safety.