Triennial Review of the Nutrient
TMDL for San Diego Creek and Upper Newport Bay
Regional Board Meeting,
Santa Ana
August 13, 2004
Water Quality Objectives
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“Waste discharges shall not contribute to excessive algal growth in receiving waters”
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“Enclosed bay and estuarine communities shall not be degraded as a result of the discharge of waste”
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TIN WQOs for San Diego Creek: 13 mg/L (Reach 1); 5mg/L (Reach 2)
[Picture of Balboa Island (Lower Newport Bay), April 1986]
[Picture of Newport Dunes (Upper Newport Bay), May 1999]
[Picture of Macroalgal Bloom Covering Mudflats in Upper Newport Bay (November 2001)]
Degradation is damage to an aquatic community or population with the result that a balanced community no longer exists.
A balanced community is (1) diverse, (2) not dominated by pollution-tolerant species…
TMDL Background/Timeline
| Pre-1970 | No macroalgal blooms |
| 1974 | First reports of macroalgae |
| 1985 | Peak macroalgal bloom |
| 1990 | Nursery WDRs issued |
| 1998 | Phased TMDL adopted |
| 2002 | 30% summer load reduction required |
| 2007 | 50% summer load reduction required |
| 2012 | 50% winter load reduction required |
[Map of Newport Bay Watershed Nurseries]
[Pie Chart of 2002 TMDL Total Nitrogen Load Allocations]
[Bar Chart of Overall Load Compliance]
[Line Graph of Summer Flow Rates in San Diego Creek]
[Line Graph of Total Nitrogen at San Diego Creek - Campus Dr. 1985-2003]
[Line Graph of Total Nitrogen at San Diego Creek - Campus Dr. 2000-2003]
[Picture of Nitrogen Removal in the IRWD Wetlands]
Summer 2002 Total Nitrogen Loads
| Source | Load (lbs) | % of Total |
|---|---|---|
| E. Costa Mesa Ch. | 187 | <0.5% |
| Bonita Canyon | 691 | 1% |
| Santa Ana Delhi Ch. | 8,686 | 15% |
| San Diego Creek | 45,507 | 80% |
| Atm. Deposition | 1,476 | 3% |
| Total | 56,547 | 100% |
| IRWD Wetlands | +33,000 | |
| Without Wetlands | 89,547 | 45% of Target |
Sediment loading (in-bay nitrogen) not included
[Bar Chart of Allocations vs. Discharge Summer 2002]
[Pie Chart of 2002 Summer Discharge: 112,018 lbs]
[Picture of Hines Nursery, August 2004]
[Picture of Hines Nursery, August 2004]
[Bar Chart of Hines Nursery Nitrogen Discharge: 1998-2004]
TMDL Task Status – Phase 1
| Task | Description | Status |
|---|---|---|
| 1 | Review SD Creek TIN Objectives | Three SCCWRP studies completed. Strategy to use DO as indicator linked with RMA model. |
| 2 | Establish new nursery permits | Nakase Bros. [Lake Forest 125 acres]: 2004 |
| 3a | Revise existing nursery permits | Bordiers: Feb. 2003, early 2004 Hines, El Modeno: 2004 |
| 3b, 3c | Revise existing NPDES permits | Orange County MS4: Jan 2002 General GW Cleanup: Jan 2002 Silverado/Caltrans: Jan ’98; Dec 2002 General GW Dewatering: end 2004 MCAS Tustin: end 2004 |
| 4 | Ag. nutrient management program | Plan approved by Board in 1999. UC Coop Extension awarded contract to implement plan: 9/2000 to 12/2003 |
| 5 | Urban Stormwater | Compliance evaluation submitted July 2000. Prop 13 contract for source characterization and BMP evaluation |
| 6 | Phosphorus Control | Sediment TMDL adopted in 1998, phosphorus allocations included in permit revisions |
TMDL Task Status, Phase 2
| Task | Description | Status |
|---|---|---|
| 1 | Monitoring: Self-monitoring or participation in RMP required | RMP approved Oct 1999. Annual reports submitted in November; |
| Regional Board to initiate investigations into unknown sources | UCR/ CSULA investigation to quantify groundwater, atmospheric deposition, and open space runoff loads; SCCWRP to investigate in-bay nitrogen 2003-2005 | |
| 2 | Review |
RB to review TMDL every 3 years; Nov, 2000; Aug 2004 |
[Picture of Lido Island (Lower Newport Bay), July 2004]
[Picture of Upper Newport Bay, November 2003]
[Picture of Upper Newport Bay, November 2003]
[Picture of Upper Newport Bay, November 2003]
[Line Graph of Dissolved Oxygen in Upper Newport Bay July 18-22, 1998]
[Picture of RMA Newport Bay Model]
Conclusions
TMDL required nutrient load reductions largely achieved
Considerable progress evident in reducing extent of macroalgal blooms
Water quality objectives still not fully achieved (fall blooms continue in Upper Newport Bay)
TMDL allocations need to be revised downward to ensure Newport Bay becomes free of macroalgal blooms
TMDL Implementation: 2004-2007
Complete studies necessary to revise water quality objectives in San Diego Creek (sediment nutrient and DO)
Develop revised (lower) TMDL allocations
Continue supporting nitrogen reduction efforts
Finalize new/revised permits (MCAS Tustin, GW dewatering, nurseries)
Reduce urban nutrient loading
Natural Treatment System/IRWD Wetlands
