Laguna de Santa Rosa TMDLs

Laguna de Santa Rosa Watershed

The Laguna de Santa Rosa is the largest tributary to the Russian River and drains a 254 square mile watershed in Sonoma County, California. Major tributaries to the Laguna de Santa Rosa include Windsor Creek, Mark West Creek, Santa Rosa Creek, Blucher Creek, and Copeland Creek. Three hydrologic subareas comprise the Laguna de Santa Rosa watershed: 114.21 Laguna Hydrologic Subarea, 114.22 Santa Rosa Hydrologic Subarea, and 114.23 Mark West Hydrologic Subarea.

• Map of the Laguna de Santa Rosa Watershed

Impairments

Not all of the above listings are being addressed at this time. The status of Total Maximum Daily Load (TMDL) development for specific pollutants is presented below.

• Currently under development:
• Nutrients (nitrogen and phosphorus)
• Dissolved oxygen
• Temperature
• Sedimentation/siltation
• Indicator bacteria – the listings in the Laguna de Santa Rosa and Santa Rosa Creek are being addressed as part of the larger Russian River Pathogen TMDL development effort. Please refer to the Russian River TMDL page for more information.
  
• Not under development at this time:
• Aluminum
• Manganese
• Mercury

Further information about the current Clean Water Act Section 303(d) List of Impaired Waters for California and the North Coast Region is available here:

• https://www.waterboards.ca.gov/northcoast/water_issues/programs/tmdls/303d/

Nutrient, Dissolved Oxygen, Temperature, and Sediment TMDLs

A TMDL for high levels of ammonia and low dissolved oxygen concentrations was approved by the US EPA in 1995 as the Waste Reduction Strategy for the Laguna de Santa Rosa.  The Waste Reduction Strategy focused on the reduction of nitrogen loading from point and non-point sources.

As mentioned above, efforts are underway by Regional Water Board staff to develop new TMDLs for nitrogen, phosphorus, dissolved oxygen, temperature, and sediment in the Laguna de Santa Rosa watershed to address continuing water quality impairments. These TMDLs will apply to the entire Laguna de Santa Rosa watershed, including Mark West Creek, Santa Rosa Creek, and all tributaries.

The objectives of the TMDL and attendant action plan will be:

1. To improve the quality of waters in the Laguna de Santa Rosa watershed so that water quality standards are attained and beneficial uses like fish habitat and human recreation are fully supported.
2. To set limits on the amounts of nitrogen, phosphorus, dissolved oxygen-demanding substances, controllable temperature factors, and sediments that can be discharged into water bodies in the Laguna de Santa Rosa watershed while still allowing for water quality standards to be attained.
3. To describe the pollutant reductions and implementation actions that will be necessary to attain water quality standards.
4. To describe the monitoring actions that will be necessary to ensure implementation actions are being executed in a manner that attains water quality standards.

Stakeholder & Community Involvement

In order for the Laguna TMDLs to be successful in addressing water quality impairments in the Laguna de Santa Rosa, it is imperative for staff to work with stakeholders and members of the community.  Stakeholders are landowners, residents, business owners, special interest groups, government officials and staff, academics, non-governmental organizations, and other interested parties. 

Regional Water Board staff developed a Stakeholder Plan in March of 2014 and aspire to implement that plan during the development of the Laguna TMDLs. To receive notices and information on the Laguna de Santa Rosa TMDLs via e-mail, please subscribe to our list service by going to the List Subscription webpage and select “Laguna de Santa Rosa TMDL” on the subscription form.

Nutrient Offset Program and Water Quality Trading Framework

To support implementation of the TMDL, the Regional Board has adopted Resolution No. R1-2008-0061 and Resolution No. R1-2018-0025 establishing the Nutrient Offset Program (NOP) and Water Quality Trading Framework (WQT), respectively. These programs are designed to reduce phosphorus loading into the Laguna and remove legacy phosphorus by creating a market for credits generated through watershed restoration projects and other nutrient reduction actions. More information can be found on the NOP and WQT by accessing the Santa Rosa Nutrient Offset Program Webpage.

Status Updates

Regional Water Board staff provides status updates to the Regional Water Board and the public on an as-needed basis. Updates since July 2010 are available below, listed in reverse chronologic order (most recent first).

• August 12, 2015 – Update on the Development of TMDLs for the Laguna de Santa Rosa (Item 5)
  Executive Officer’s Summary Report
  Presentation Slides

• November 20, 2014 – Update on the Development and Early Implementation of the Laguna de Santa Rosa TMDLs for Nutrients, Dissolved Oxygen, Temperature, and Sediment (Item 10)
  Executive Officer’s Summary Report
  Presentation Slides

• December 6, 2012 – Update on the Development of the Laguna de Santa Rosa TMDLs for Nitrogen, Phosphorus, Dissolved Oxygen, Temperature, and Sediment (Item 11)
  Executive Officer’s Summary Report
  Presentation Slides

• January 27, 2011 – Update on Lower Russian River Core Regulatory and TMDL Efforts (Item 13)
  Executive Officer’s Summary Report
  Presentation Slides

• July 15, 2010 – Update on the Status of Russian River Watershed TMDL Development Projects (Item 9)
  Executive Officer’s Summary Report
  Presentation Slides

Monitoring Plans & Reports

Regional Water Board staff completed the majority of the monitoring to support the development of the TMDL source analyses.  The following documents detail the monitoring plan, Quality Assurance Project Plan, and results.

• Monitoring Plan - June 2008
• Quality Assurance Project Plan - June 2008
• 2008 Source Analysis Monitoring Report Appendices - December 2008
• 2008 Source Analysis Monitoring Report - December 2008
• 2009 Source Analysis Monitoring Report - November 2010
• 2009 Source Analysis Monitoring Report Appendices - June 2010
• Diel Water Quality Monitoring Report - December - 2011

Technical Memoranda

Several Regional Water Board staff technical memoranda document and describe analyses and assessments to support the development of the TMDLs. These memoranda and their findings and conclusions are subject to change as staff continue to develop the TMDLs. They are listed in reverse chronological order (most recent first).

• Assessment of the Total Nitrogen and Ammonia Nitrogen Goals from the 1995 Laguna TMDL - May 2012
• Assessment of Nutrients Limiting Algal Biomass Production in the Laguna de Santa Rosa - March 2012
• Dissolved Oxygen Model Application for Pre-Settlement Laguna Watershed Conditions - March 2012
• Laguna de Santa Rosa TMDL Linkage Analysis through Application of Water Quality Models - March 2012
• Laguna de Santa Rosa TMDL Linkage Analysis and Loading Capacity Assessment for Total Nitrogen and Ammonia Nitrogen Toxicity - March 2012
• Descriptive Statistics of Diel Water Quality collected within the Laguna de Santa Rosa Watershed during the years 1995 through 2011 - December 2011
• Development of the Laguna de Santa Rosa Watershed Pre-European Settlement Spatial Data Model - December 2011
  • Development of the Land Cover Loading Model for the Laguna de Santa Rosa Watershed - December 2011 (Under Revision)
  • Diel Water Quality within the Laguna de Santa Rosa Watershed during 2001-2002 - October 2011
• Dissolved Oxygen Model Development and Evaluation - June 2011
• Constructing Stream Flow Rating Power Equations for the Pre-settlement Lakes in the Laguna de Santa Rosa Watershed - June 2011
• Sediment Quality of the Laguna de Santa Rosa - May 2011
• Water Quality Model Development History for the Laguna de Santa Rosa TMDL - May 2011
• Pre-European Settlement Spatial Data Model Evaluation - November 2010
• Gradient Analysis of Environmental Variables to Delineate Pre-European Settlement Land Cover Boundaries - November 2010
•  (currently under revision)
• Nutrient Loading Estimates for Laguna TMDL Source Analysis - November 2010

Other Available Documents

A number of additional documents pertinent to Regional Water Board staff's development of Total Maximum Daily Loads (TMDLs) for the Laguna de Santa Rosa watershed are available below.

• Laguna de Santa Rosa Sediment Budget (Main Report) – Tetra Tech (2015)
  
• Laguna de Santa Rosa Sediment Budget (Appendices) – Tetra Tech (2015)
  
• Laguna de Santa Rosa Nutrient Analysis – Tetra Tech (2015)
  
• The Altered Laguna: A Conceptual Model for Watershed Stewardship - A report by Christina Sloop, Joseph Honton, Clayton Creager, Limin Chen, Elizabeth Andrews, and Setenay Bozkurt from the Laguna de Santa Rosa Foundation, Tetra Tech, Inc., and Philip Williams & Associates, Ltd. (2007)
  
• County Sanitary Survey – Lee (1944)