Laguna de Santa Rosa TMDLs

Impairments  |  Nutrient, Dissolved Oxygen, Temperature & Sediment TMDLs  |  Pathogen & Indicator Bacteria TMDLs

Mercury Impairment  |  Other Available Documents 

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.

This web page provides information specific to the development of Total Maximum Daily Loads for the Laguna de Santa Rosa. Click this link for information on other projects, programs, and efforts in the Laguna de Santa Rosa watershed.

Impairments

Middle Russian River HA
Laguna HSA
tributaries to the Laguna de Santa
Rosa (except Santa Rosa Creek)

Mainstem Colgan Creek

Oxygen, Dissolved

Entire water body

Indicator Bacteria

Sedimentation/Siltation

Temperature

Middle Russian River HA
Mark West HSA
mainstem Mark West Creek
downstream of the confluence
with the Laguna de Santa Rosa

Entire water body

Aluminum

Oxygen, Dissolved

Phosphorus

Manganese

Sedimentation/Siltation

Temperature

Middle Russian River HA
Mark West HSA
mainstem Mark West Creek
upstream of the confluence with
the Laguna de Santa Rosa

Entire water body

Sedimentation/Siltation

Temperature

Middle Russian River HA
Mark West HSA
tributaries to Mark West Creek
(except Windsor)

Entire water body

Sedimentation/Siltation

Temperature

Middle Russian River HA
Mark West HSA
Windsor Creek and its tributaries

Entire water body

Sedimentation/Siltation

Temperature

Middle Russian River HA
Santa Rosa HSA
mainstem Santa Rosa Creek

Entire water body

Indicator Bacteria

Sedimentation/Siltation

Temperature

Middle Russian River HA
Santa Rosa HSA
tributaries to Santa Rosa Creek

Spring Lake

Mercury

Entire water body

Indicator Bacteria

Sedimentation/Siltation

Temperature

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:

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).

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.

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).

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.

Mailing Lists

To receive notices and information on the Laguna de Santa Rosa TMDLs via e-mail, please subscribe to our list service by clicking here and select “Laguna de Santa Rosa TMDL” on the subscription form.

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