The Delta Nutrient Research plan continues to determine whether numeric water quality objectives for nutrients are needed in the Sacramento-San Joaquin Delta.
The Measure
Concentrations and/or loads of bio-stimulatory substances (inorganic nutrients) in Delta waters is reduced.
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Expectations
Reduce excessive amounts of bio-stimulatory substances (inorganic nutrients such as ammonium, nitrate, and phosphate), or altered proportions of these nutrients in Delta waters.
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Performance Metrics
- Concentrations and/or loads of bio-stimulatory substances at Delta water quality monitoring locations, evaluated annually.
Data Background
Nutrient sampling and testing is conducted by USGS. The sampling starts in the lower Sacramento River and extends to South San Francisco Bay.
Currently, there is no target for this performance measure. The target is dependent on whether the Delta Nutrient Research Plan (DNRP) identifies if water quality objectives for nutrients are needed in the Delta. Additional discussion regarding the DNRP can be found below.
Bio-stimulatory substances are inorganic nutrients that are an essential part of the ecosystem and include: Ammonium (NH4), Nitrate (NO3), Phosphate (PO4).
Without these nutrients, ecosystems cannot survive. Naturally, nutrients are a limited resource for living organisms and primary producers (plants, bacteria, algae) compete for them. Human activities contribute to excess nutrients in the ecosystem. Excessive concentrations and loads become detrimental to humans and wildlife by affecting water quality and ecosystem populations.
One major source of nutrients to the Delta is sewage effluent. Sewage effluent, along with other factors such as temperature and low water flow, can stimulate algal growth in the Delta and reservoirs. Elevated nutrients can increase nonnative aquatic vegetation (for example water hyacinth) that can clog up waterways, decrease light penetration, disrupt food webs by shifting algal species composition from diatoms to less nutritious forms of algae, and cause taste and odor problems with drinking water. A reduction in inorganic nutrient concentrations may reduce the frequency or intensity of water quality issues.
Currently, numeric water quality objectives for nutrients are not determined. As of July 2018, the Delta Nutrient Research Plan calls for additional work to understand nutrients’ impacts before nutrient water objectives can be considered. By monitoring specific inorganic nutrients, programs can begin to develop a control or regulatory strategy to address issues related to nutrient impairment.
Each chapter of the Delta plan includes strategies to achieve the goals of the plan. These strategies are general guidance on achieving the objective laid out in the plan and in the Delta Reform Act of 2009. Associated with these strategies are recommendations. The recommendations describe more specific and implementable actions to support the achievement of Delta Plan strategies. Strategies and recommendations may also have associated performance measures. Delta Plan performance measures track progress in achieving desired outcomes for the Delta Plan. Below are the strategies and recommendations associated with this performance measure.
Delta Plan Strategy
- Improve environmental water quality
Delta Plan Recommendations
- Completion of regulatory processes, research, and monitoring for water quality improvements
- Implement Delta Regional Monitoring Program
- Evaluate wastewater recycling, reuse, or treatment
- Manage dissolved oxygen in Stockton Deep Water Ship Channel
- Manage dissolved oxygen in Suisun Marsh
The Delta Nutrient Research Plan (DNRP) was completed and accepted by the Central Valley Regional Water Quality Control Board in August 2018. To summarize, the DNRP identifies information gaps for determining whether water quality objectives for nutrients are needed to address issues such as harmful algal blooms, invasive aquatic plants, dissolved oxygen impairment, and primary production within the Delta. Efforts are now focused on obtaining funding and filling the gaps through special studies, monitoring, data evaluation, and modeling. Short term activities are also identified, which focuses on completing existing projects and expanding collaboration and coordination with other entities with prioritized efforts to address harmful algal blooms and evaluating thresholds, benchmarks and management approaches utilized in other areas.
Additional information regarding the DNRP can be found on the State Water Board's website.
Wastewater effluent is one major source of nutrients to the Delta. A major project that will help reduce nutrient loads is Sacramento Regional County Sanitation District's (Regional San) EchoWater Project; it is located on the lower Sacramento River. The project was completed in May 2023.
The EchoWater Project reduces ninety-nine percent of ammonia and eighty-nine percent of nitrogen from wastewater discharged from the Sacramento Regional Wastewater Treatment Plant to the Delta.
Metric
Concentrations and/or loads of bio-stimulatory substances (inorganic nutrients such as ammonium, nitrate, and phosphate) at Delta water quality monitoring locations, evaluated annually.
Baseline
Bio-stimulatory substance concentrations, loads, and trends during the period of 2004-2013.
Target
Meet the limits and targets identified by the Delta Nutrient Science and Research Program by 2034.
Data are retrieved from USGS Water quality of San Francisco Bay. Data queried for the following nutrients: Nitrite+Nitrate, Ammonium, and Phosphate. Sample Data in the Sacramento River and Suisun Marsh are averaged.
Data Sources: