the implementation of a TMDL under the water quality conditions that exist in SIYB. This 

TMDL for dissolved copper is necessary to ensure attainment of applicable water quality 

objectives and restoration of beneficial uses designated for SIYB. 

3. CLEAN WATER ACT SECTION 303(d): The SIYB portion of San Diego Bay was 

placed on the Clean Water Act section 303( d) list of impaired waters in 1996 due to elevated 

levels of dissolved copper in the water column. 

4. BENEFICIAL USE IMPAIRMENTS: SIYB supports the same suite of beneficial uses as 

San Diego Bay. The most sensitive beneficial uses are those designated for protection of 

marine aquatic life and aquatic dependent wildlife as described in the Basin Plan definition of 

the marine habitat (MAR) and wildlife habitat (WILD) beneficial uses. The MAR and· 

· WILD beneficial uses of SIYB are threatened or impaired due to elevated levels of dissolved 

copper. 

5~ WATER QUALITY OBJECTIVES: The water quality objectives for copper in SIYB 

specify that concentrations in seawater for dissolved copper should not exceed . 

3.1 micrograms/liter (!lg/L) for continuous or chronic exposures (not to be exceeded over a 

four-day average), and 4.8 !lg/L of copper for brief or acute exposures (not to be exceeded 

over a one-hour average). These water quality objectives are based on, and equal, to the 

California Toxics Rule (CTR) water quality criteria for dissolved copper promulgated by the 
Pesticide Objective: No individual pesticide or combination of pesticides shall be present in 

the water column, sediments, or biota at concentration( s) that adversely affect beneficial 

uses. Pesticides shall not be present at levels that will bioaccumulate in aquatic organisms 

to levels harmful to human health, wildlife or aquatic organisms. 

Meeting the numeric water quality objectives for copper will ensure that the narrative 

toxicity and pesticides objectives are met in the water column with respect to copper. 

6. NUMERIC TARGETS: TMDL Numeric Targets interpret and implement water quality 

standards (i.e., numeric and narrative water quality objectives and beneficial uses) and are 

established at levels necessary to achieve water quality standards. The Regional Board has 

set the copper TMDL Numeric Targets for both the numeric and narrative water quality 

objectives equal to the numeric water quality objectives for copper cited in Finding 5. The 

numeric targets for dissolved copper are 3.1 ).lg/L for continuous or chronic exposure (4-day 

average) and 4.8 ).lg/L (1-hour average) for brief or acute exposures. Attainment of the 

TMDL numeric targets will result in attainment of water quality standards in SIYB. 

7. SOURCES OF DISSOLVED COPPER: Approximately 98 percent of the total copper 

loading to SIYB originates from copper-based antifouling paints applied to the hulls of 

recreational vessels moored in SIYB marinas. Of this total, 93 percent is attributable to 

2 
banned in parts of Europe. 

10. TOTAL MAXIMUM DAILY LOAD: [40 Code of Federal Regulations (CPR), section 

130.2(i)] The TMDL for copper discharges into SIYB is calculated to be 1.6 kilograms of 

copper per day (kg/day), or 567 kilograms of copper per year (kg/year). The TMDL is 

defined as the maximum amount of copper that SIYB can receive and still attain water 

quality objectives and protection of designated beneficial uses. The TMDL is comprised of 

the sum of all individual Wasteload Allocations (WLAs) for point source discharges of 

copper, the sum of all Load Allocations (LAs) for nonpoint source discharges of copper, and 

background. The TMDL includes a margin of safety (MOS) that takes into account any 

uncertainties in the TMDL calculation. (i.e. TMDL = WLAs +LAs+ MOS). The TMDL 

calculations also account for seasonal variations and critical conditions. 

11. ALLOCATIONS AND REDUCTIONS: A 76 percent overall reduction of residual copper 

loading to SIYB is required to meet the TMDL of 567 kg/year. The assigned allocations from 

each source translate into a percent reduction of dissolved copper from current loading. 

Loading due to passive leaching must be reduced by 81 percent from current loading. 

Loading due to underwater hull cleaning must be reduced by 28 percent from current 

loading. From an overall perspective, passive leaching loading must be reduced by 

75 percent from the combined total loading of all sources to SIYB. Underwater hull cleaning 

3 
subsequent 15-year reduction period is comprised of three stages during which incremental 

copper load and wasteload reductions are required. 

17. SCIENTIFIC PEER REVIEW: The scientific basis of this TNIDL has undergone external 

peer review pursuant to Health and Safety Code section 57004. The Regional Board has 

considered and responded to all comments submitted by the peer review panel. 

18. STAKEHOLDER PARTICIPATION: Interested persons and the public have had 

reasonable opportunity to participate in review of the amendment to the Basin Plan. A 

California Environmental Quality Act (CEQA) scoping meeting was held on March 19, 

2003. Efforts to solicit public review and comment included three public workshops held 

·between May 2000 and December 2003; a public review and comment period of 90 days 

preceding and following the Regional Board public hearing; a second public comment period 

of 30 days following the release of the revised TMDL Technical Report dated October 14, 

2004; and written responses from the Regional Board to oral and written comments received 

from the public. 

19. ECONOMIC ANALYSIS: The Regional Board has considered the costs of reasonably 

foreseeable methods of compliance with the load and wasteload reductions specified in this 

TMDL. 

4 
24. BASIN PLAN ORGANIZATION: Basin Plan Chapter 4, Implementation needs to be 

reorganized to create a subsection in which to include the Shelter Island Yacht Basin 

Dissolved Copper TMDL, and the Chollas Creek Diazinon TMDL Basin Plan amendments, 

and any future TMDL Basin Plan amendments. 

NOW, THEREFORE, BE IT RESOLVED that 

1. AMENDMENT ADOPTION: The Regional Board hereby adopts this amendment to the 

Basin Plan to incorporate the Shelter Island Yacht Basin Dissolved Copper TMDL, and to 

reorganize Chapter 4 as set forth in Attachment A hereto. 

2. TECHNICAL REPORT APPROVAL: The Regional Board hereby approves the 

Technical Report for Total Maximum Daily Load for Dissolved Copper In Shelter Island 

Yacht Basin, San Diego Bay, dated February 9, 2005. 

3. CERTIFICATE OF FEE EXE:MPTION: The Executive Officer is authorized to sign a 

Certificate of Fee Exemption. 

4. AGENCY APPROVALS: The Executive Officer is directed to submit this Basin Plan 

amendment to the State Board in accordance with CWC section 13245. The Regional Board 

requests that the State Board approve the Basin Plan amendment and forward it to Office of 

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Chapter 4, Total Maximum Daily Loads. 

Chapter 3, Water Qualitv Objectives 

Inland Surface Waters, Enclosed Bays and Estuaries, Coastal Lagoons, and Ground 

Waters 

Water Quality Objectives for Pesticides: 

Add a third paragraph as follows: 

The Shelter Island Yacht Basin portion of San Diego Bay is designated as an 

impaired water body for dissolved copper pursuant to Clean Water Act section 

303(d). A Total Maximum Daily Load (TMDL) has been adopted to address this 

impairment. See Chapters 2, Table 2-3, Beneficial Uses of Coastal Waters, San 

Diego Bay, Footnote 3 and Chapter 4, Total Maximum Daily Loads. 

Water Quality Objectives for Toxicity: 

Add a fourth paragraph as follows: 

The Shelter Island Yacht Basin portion of San Diego Bay is designated as an 

impaired water body for dissolved copper pursuant to Clean Water Act section 

303(d). A Total Maximum Daily Load (TMDL) has been adopted to address this 
Remove 

(TMDL) from the title of the subsection Total Maximum Daily Load (TMDL)for 

Diazinon, Chollas Creek Watershed, San Diego County" and move this subsection from "Other 

Programs'' into the section "Clean Water Act Section 303(d) Requirements for Impaired 

W aterbodies." 

After the subsection on the Chollas Creek Diazinon TNIDL add the following subsection: 

Total Maximum Daily Load for Dissolved Copper, Shelter Island Yacht Basin, San Diego Bay 

On February 9, 2005, the Regional Board adopted Resolution No. R9-2005-0019, A Resolution 

Adopting an Amendment to the Water Quality Control Planfor the San Diego Region to 

Incorporate a Total Maximum Daily Load for Dissolved Copper in the Shelter Island Yacht 

Basin, San Diego Bay. The TNIDL Basin Plan Amendment was subsequently approved by the 

State Water Resources Control Board on [Insert Date], the Office of Administrative Law on 

[Insert Date], and the United States Environmental Protection Agency on [Insert Date]. The 

TMDL is described in the Total Maximum Daily Load for Dissolved Copper in Shelter Island 

Yacht Basin, San Diego Bay, Technical Report dated February 9, 2005. 

2 
antifouling paints applied to the hulls of recreational boats. The passive leaching of copper from 

antifouling paint is 93 percent of the total loading. The remaining five percent of total copper 

loading results from underwater hull cleaning operations in SIYB. 

Table 4-11. Summary of Dissolved Copper Sources to SIYB. 

Source Mass Load (kg/year) Percent Contribution 

(% Cu) 

Passive Leaching 2,000 93 

Hull Cleaning 100 5 

Urban Runoff 30 ] 

Background 30 I 

Direct Atmospheric 3 <1 

Deposition 

Sediment 0 0 

Combined Sources 2,163 100 

Total Maximum Daily Load 

The TMDL or loading capacity for dissolved copper discharges into SIYB is 1.6 kilograms/day 

(kg/day) or 567 kilograms/year (kg/year). 

3 
Atmospheric 

Deposition 

Sediment 0 0 0 0 0 

Current Mass 2,163 100 0 

Load 

Mar !lin of Safetv 57 0 

TMDL 567 0 

Total Load 76 76 

Reduction 

Recalculations if Water Quality Objectives Change 

If the water quality objectives for dissolved copper in SIYB are changed in the future, then the 

MOS, TlviDL and allocations will be recalculated using the method shown in Appendix D of the 

Basin Plan. 

4 
Copper load and wasteload reductions are required over a 17-year staged compliance schedule 

period. 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 and wasteload reductions are required as shown 

below. 

Table 4-13. Interim Loading Targets for Attainment of the TMDL. 

Stage Time Percent Reduction Reduction to be Estimated Interim 

Period from Current Attained by Target Loading 

Estimated Loading End of Year (kg/year of 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 

At the end of the Basin Plan, add the following Appendix D: 

5 
where C1 = average background concentration of copper measured in the area of San Diego Bay 

adjacent to SIYB, expressed as total copper, (0.05 ~-tg!L) 

C2 =average target concentration for copper in the SIYB (expressed as total copper) 

when the maximum concentration of copper in SIYB is equal to or less than the 

numeric target (mass/volume) 

K = dispersion coefficient calculated from salinity measurements and mixing length 

approximation (15.3 m

2

/sec) 

Ac =cross-sectional area of entrance to SIYB (1,000 m

2

) 

As =surface area of SIYB (740,000 m

2

) 

Ax = average mixing length between SIYB and adjacent area; estimated distance between 

the endpoints for sl and s2 (2,000 m) 

V2 =volume of SIYB (31,000,000 m

3

) 

e = evaporation rate (0.43 em/day) 

k1 =rate of total copper loss to sediment (7%/day) 

Rs =loading capacity, expressed as total copper (mass/time); Rs is calculated iteratively to 

find the maximum possible value that does not cause C2 to exceed the numeric 

target. 

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(4) TMDL=Rs-MOS 

Allocations 

Equation 5 is used to determine the new allocation for passive leaching. In equation 5, the only 

variable is the allocation for passive leaching (Ap), while the other source allocations are 

constants. The allocation for hull cleaning remains the same, since it was based on the 

assumption that all of the divers will use Management Practices (MPs) to clean boat hulls that 

have copper bottom paints. Allocations for the other sources, namely urban runoff, background 

and sediment will not be recalculated because these sources of copper are insignificant. 

(5) TMDL = Wasteload Allocation+ Load Allocations+ MOS 

where: 

TMDL=Au +Ap+Ah +As+ Ab +Aa+ MOS 

Au = allocation for urban runoff= 30 kg/year 

Ap =allocation for passive leaching 

Ah = allocation for hull cleaning = 72 kg/year 

1 USEPA. 2000. Water Quality Standards; Establishment of Numeric Criteria for Priority Toxic Pollutants for the 

State of California; Rule. 40 CFR Part 131. May 18, 2000. 

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