TMDL for Nutrients in Lower Salinas River Watershed, Monterey County, California

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 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, it emphasizes that 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

Watershed Description

Gabby

Problem Statement

Shaelyn

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 what the location of the water bodies withing 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"(ref nutrient 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

• accounts for uncertainty in the linkage between water temperature and nutrient pollutant concentration in the receiving water body

Critical Conditions and Seasonal Variation

Roger

TMDL Allocations

Roger

Public Participation

Michelle

Implementation and Monitoring

Michelle

Links

• TMDLs in the Monterey Bay Region of California

• Central Coast Ambient Monitoring Program

• Central Coast Watershed Studies Team

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.