Difference between revisions of "TMDL for Nutrients in Lower Salinas River Watershed, Monterey County, California"

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(TMDL Allocations)
(TMDL Allocations)
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TMDL allocations refer to the total concentration of nutrients allowed to be discharged into a water body by all possible sources.  The allocations is typically comprised of nonpoint sources and point sources and can include a safety margin to account for unexpected sources of a particular contaminant.
 
TMDL allocations refer to the total concentration of nutrients allowed to be discharged into a water body by all possible sources.  The allocations is typically comprised of nonpoint sources and point sources and can include a safety margin to account for unexpected sources of a particular contaminant.
  
The Lower Salinas River Watershed Nutrient TMDL [http://www.swrcb.ca.gov/centralcoast/water_issues/programs/tmdl/docs/salinas/nutrients/sal_nut_dataanalyrpt_061410.pdf Progress Report] has established numeric targets for nutrient loading into different water bodies.  TMDL allocations have not been proposed however until the [Ag Waiver] process is revised and finalized.
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The Lower Salinas River Watershed Nutrient TMDL [http://www.swrcb.ca.gov/centralcoast/water_issues/programs/tmdl/docs/salinas/nutrients/sal_nut_dataanalyrpt_061410.pdf Progress Report] has established numeric targets for nutrient loading into different water bodies, but has not provided recommended allocation for nutrient reduction.   
  
 
==Public Participation==
 
==Public Participation==

Revision as of 09:35, 11 April 2011

This summary page is based on the Regional Water Quality Control Board Central Coast Region progress report on Total Maximum Daily Load for Nutrients and other TMDL projects for the Lower Salinas River Watershed, in Monterey County, California. This summary was prepared by the Spring 2011 ENVS 560/L Watershed Systems class at CSUMB.

Project Definition

The California Regional Water Quality Control Board for the Central Coast Region (CCRWQCB) is currently developing a Total Maximum Daily Load (TMDL) project for nutrients in the Lower Salinas River Watershed in Monterey County. The CCRWQCB presented a progress report in June 2010 that contains background information, provisional nutrient targets, and a compilation of water quality data of water bodies in the region. Although the progress report identifies potential sources of nutrient loads, the source analysis portion of the TMDL project is still pending.

This TMDL project will address the nutrient related impairments in the 303(d) listed water bodies of the Lower Salinas River watershed. The 2006 303(d) List of Impaired Waterbodies is the current and active list for the California Central Coast. In 2010 the CCRWQCB presented an updated list in its 2010 Integrated Report, but this report is still waiting for approval by the USEPA. The following table contains the water bodies and the nutrient-related reason for their listing in both the 2006 active list and in the 2010 list:


Water Body 2006 Listed Impairment 2010 Listed Impairment
Alisal Creek Nutrient Chlorophyll-a, Nitrate
Alisal Slough Not Listed Low Dissolved Oxygen, Nitrate
Blanco Drain Not Listed Low Dissolved Oxygen, Nitrate
Chualar Creek Not Listed Ammonia (Unionized), Nitrate
Esperanza Creek Not Listed Nitrate
Espinosa Slough Not Listed Ammonia (Unionized), Nitrate
Gabilan Creek Nitrate Ammonia (Unionized), Nitrate
Merrit Ditch Not Listed Ammonia (Unionized), Low Dissolved Oxygen, Nitrate
Moro Cojo Slough Ammonia (Unionized),Low Dissolved Oxygen Ammonia (Unionized), Low Dissolved Oxygen
Natividad Creek Nitrate Ammonia (Unionized), Low Dissolved Oxygen
Old Salinas River Not Listed Chlorophyll-a, Low Dissolved Oxygen, Nitrate
Old Salinas River Estuary Ammonia (Unionized), Low Dissolved Oxygen, Nutrients Nutrients
Quail Creek Nutrients Ammonia (Unionized), Low Dissolved Oxygen, Nitrate
Salinas Reclamation Canal Ammonia (Unionized), Low Dissolved Oxygen Ammonia (Unionized), Low Dissolved Oxygen, Nitrate
Salinas River (lower, estuary to near Gonzales Rd

Crossing)

Nitrate, Nutrients Nitrate
Salinas River Lagoon (North) Nutrients Nutrients
Santa Rita Creek Nitrate Ammonia (Unionized), Low Dissolved Oxygen, Nitrate
Tembladero Slough Ammonia (Unionized), Nutrients Chlorophyll-a, Nitrate, Nutrients


Problem Statement

Sources contributing to the issue of nutrients in the Lower Salinas Watershed have not yet been identified. In general, sources of nutrients in watersheds include: urban runoff; the application of fertilizers; groundwater; livestock; wastewater treatment plants; septic systems.

Beneficial Uses (BUs) of Listed Waterways

  • Municipal and Domestic suppy (MUN)
  • Agriculture (AGR)
  • Industrial Process (PRO)
  • Industrial Service (IND)
  • Ground Water Recharge (GWR)
  • Water Contact Recreation (REC1)
  • Non-Contact Water Recreation (REC2)
  • Cold Freshwater Habitat (COLD)
  • Warm Freshwater Habitat (WARM)
  • Estuarine Habitat (EST)
  • Wildlife Habitat (WILD)
  • Rare, Threatened, or Endangered Species (RARE)
  • Migration of Aquatic Organisms (MIGR)
  • Spawning, Reproduction, and/or Early Development (SPWN)
  • Biological Habitats of Special Significance (BIOL)
  • Shellfish Harvesting (SHELL)
  • Commercial and Sport Fishing (COMM)
  • Freshwater replenishment (FRESH)
Waterbody MUN AGR PRO IND GWR REC1 REC2 WILD COLD WARM MIGR SPWN BIOL RARE EST FRESH COMM SHELL
Old Salinas River Estuary X X X X X X X X X X X X
Salinas River Lagoon (North) X X X X X X X X X X X X
Tembladero Slough X X X X X X X X X
Espinosa Slough X X X X X
Salinas Reclamation Canal X X X X X
Alisal Creek X X X X X X X X X X
Blanco Drain X X X X X
Salinas River, down stream of Spreckels Gage X X X X X X X X X
Salinas River,Chualar to Spreckles X X X X X X X X X X X X
Quail Creek X X X X

A more complete table of beneficial uses will be available in the final project report.

Data Analysis

Shaelyn

Numeric Target

Kathy

Linkage Analysis

Kathy

TMDL Development

Natalie

  • target concentration

The TMDL target for nutrients for the lower Salinas valley is identified as a numeric target. The target concentrations vary based on the locations of the water bodies within the Salinas Valley. These preliminary target concentrations are based on the 95th percentile of CCAMP reference sites. These reference sites might not be representative of "valley floor streams, sloughs and water conveyance structures"(progress report), which are more commonly found in the Salinas Valley.

The target allowable concentrations are established for phosphorus and nitrogen. The allowable numeric targets were calculated using the NNE (nutrient numeric endpoints) benthic biomass predictor tool. This tool predicts biological responses based on nutrient conditions present in the water body. The numeric targets for nutrient concentration are temperature dependent. The classifications for water temperature are either warm or cold. Parameters that are included in the predictor tool include nutrients (natural and anthropogenic), canopy closure, water temp, latitude, flow velocity and depth.

  • goal
  • allowable levels
    • The provisional target concentrations are -table on page 107
  • example?

Margin of Safety

Natalie

A margin of safety is used to account for the uncertainty in the linkage between nutrient loads and nutrient the nutrient pollutant concentrations in the receiving water body.

  • SLO calculated nutrient TMDL margin of safety "based on the difference between the total maximum daily load and the allocated load"
    • "takes into account any lack of knowledge concerning the relationship between effluent limitations and water quality"
  • Uncertainties accounted for in the margin of safety include...
    • limited data(how many years do we have?)
    • these discrete values have been estimated based on a specific amount of parameters and categorized primarily based on temperature and does not necessarily account for the interaction of the parameters
    • model may not be represnetative of the actual environmental conditions
  • rain patterns vary from one year to the next so dilutions vary
  • is it built in?
  • whats the order of magnitude-range of margins of saftey
    • the basis for this
    • typical example
  • range that one might want to consider is ...

Critical Conditions and Seasonal Variation

The TMDL progress report has not addressed the “critical” environmental factor for nutrient loading in the Lower Salinas River Watershed, in which a slight change could lead to exceeding the water quality objectives. However, the progress report does specify some indicators that can impair the beneficial uses of the regional water bodies (progress report).

Previous TMDLs in the Lower Salinas River Watershed have not included critical conditions (TMDLs in the Monterey Bay Region of California), however critical conditions for a Nutrient TMDL may be advisable due to the high occurrence of nutrient loading for agriculture in the Salinas Valley. The TMDL approved for the Santa Clara River in 2003 included critical conditions (Santa Clara River Nitrogen TMDL). Although the climate around the Santa Clara River is drier, that water body is similar to the Lower Salinas River in seasonal flow and the effects of the first big storm (first flush). Although not a perfect approach (Keller et al. 2004), the Santa Clara River TMDL makes an attempt to incorporate the increased impairment hazard presented by seasonal variation [1].

TMDL Allocations

TMDL allocations refer to the total concentration of nutrients allowed to be discharged into a water body by all possible sources. The allocations is typically comprised of nonpoint sources and point sources and can include a safety margin to account for unexpected sources of a particular contaminant.

The Lower Salinas River Watershed Nutrient TMDL Progress Report has established numeric targets for nutrient loading into different water bodies, but has not provided recommended allocation for nutrient reduction.

Public Participation

Public participation is a requirement of the TMDL process and is vital to a TMDL’s success. The August 23, 1999, proposed regulation states that the public must be allowed at least 30 days to review and comment on a TMDL prior to its submission to the EPA for review and approval. In addition, with a TMDL submittal, the EPA must be provided with a summary of all public comments received regarding the TMDL and staff response to those comments, indicating how the comments were considered in the final decision. During the completion of past TMDLs the Central Coast Water Board presented TMDL project reports during different stages of the analysis process and to present preliminary findings of the report. California Environmental Quality Act (CEQA) issues will likely need to be addressed as well. It is most effective to prepare documents ahead of time to demonstrate any potential impacts and present alternative schemes and implementation strategies to the public. [2]

Implementation and Monitoring

Monitoring

The EPA protocol document [2] suggested steps: identify key questions, evaluate monitoring options and implement the monitoring program. It is suggested that monitoring plans describe the timing, location, responsible parties, and quality assurance and control procedures. The level of rigor required for a monitoring plan is dependent on the confidence in the TMDL analysis. A greater level of uncertainty requires more rigorous monitoring actions and must allow more room for future revision. Since watershed process drivers are not identical before and after implementation, models are useful for evaluating results of monitoring. Models can be calibrated to pre or post implementation to better compare results of monitoring actions. Coordination with other existing or planned monitoring activities can be particularly helpful for long-term monitoring programs, large study areas, or if the water quality agency’s monitoring resources are limited. It is also important to choose the type of monitoring that will be most appropriate to yield desired goals and then develop a quality assurance plan to ensure the data can support future analysis. Overall a monitoring plan is created to evaluate the effectiveness of the implementation strategies and TMDL elements such as numeric targets and pollutant estimates.

Examples of key questions:

  • Are the selected indicators capable of detecting designated use impacts of concern and responses to control actions?
  • Have baseline or background conditions been adequately characterized?
  • Are the numeric targets set at levels that reasonably represent the appropriate desired conditions for designated uses of concern?
  • Have all important pollutant sources been identified?
  • Have pollutant sources been accurately estimated?

Implementation

References

  1. Keller AA, Zheng Y, Robinson TH. 2004. Determining critical water quality conditions for inorganic nitrogen in dry, semi-urbanized watersheds. JAWRA 40(3): 721-735. Available from: http://onlinelibrary.wiley.com/doi/10.1111/j.1752-1688.2004.tb04455.x/abstract
  2. 2.0 2.1 [1]

Links

Disclaimer

This page may contain student work completed as part of assigned coursework. It may not be accurate. It does not necessary reflect the opinion or policy of CSUMB, its staff, or students.