TMDL Projects - Clear Lake Nutrient Control Program and TMDL
On This Page
Information Regarding the Status of Load Allocations
Through 2019 and 2020, Central Valley Water Board requested additional information and issued Enforcement Orders to responsible parties named in the Clear Lake Nutrient TMDL. The information provided from responsible parties was used to determine whether the parties are in compliance with the TMDL and summarized in the Technical Memorandum released in September 2021.
- 2016 Enforcement Order Issued to Caltrans
- Caltrans Response to 2016 Enforcement Order
- 2020 Enforcement Order Issued to Irrigated Agriculture
- Irrigated Agriculture Response to 2019 Enforcement Order
- Additional Information Submitted by Irrigated Agriculture in 2016:
- Winegrape Memo
- Lake County Inspections
- Lake County BMP Work Plan Approval Letter
The Central Valley Waterboard has approved the Work Plan and considers Lake County's obligation under the 13267 Order fulfilled.
- 2021 Enforcement Order Issued to Lake County
- Time Schedule Order
- Tentative Time Schedule Order
- 2019 Enforcement Order Issued to Lake County
- 2016 Enforcement Order Issued to Lake County
- Lake County Response to 2016 Enforcement Order
- Additional Information Submitted by Lake County in 2016:
- Sediment Phosphorus Trend Analysis
- Clear Lake Historical Data Analysis
- Cyanobacteria as Biological Drivers
- Lake County Watershed Protection District & County of Lake Department of Water Resources Grant Funding Summary 2000-2016
- Lake County Clean Water Program Report FY 16/17
- Lake County Clean Water Program Report FY 14/15 and 15/16
U.S. Bureau of Land Management (USBLM)
- 2020 Enforcement Order Reissued to USBLM
- 2019 Enforcement Order Issued to USBLM
- 2016 Enforcement Order Issued to USBLM
- USBLM Response to 2016 Enforcement Order
- Additional Information Submitted by USBLM in 2016:
- 8 Mile Restoration Project Grant Agreement
U.S. Forest Service (USFS)
- 2020 Enforcement Order Issued to U.S. Forest Service
- 2016 Enforcement Order Issued to USFS
- USFS Response to 2016 Enforcement Order
Blue Ribbon Committee for the Rehabilitation of Clear Lake
The Blue Ribbon Committee for the Rehabilitation of Clear Lake, created by Assembly Bill 707 (Aguiar-Curry, Ch. 842, Statutes of 2017), was formed to make recommendations that will rehabilitate and restore Clear Lake. The Committee consists of 15 members, which includes representatives from tribes, UC Davis, the Central Valley Regional Water Quality Control Board, and members appointed by Lake County with expertise in agriculture, economics, environment and public water supplies. The Central Valley Regional Water Quality Control Board representative is Jennifer LaBay. The alternate representative from the Board is previous Board Member Robert Schneider.
More information regarding the Blue Ribbon Committee for the Rehabilitation of Clear Lake, along with Committee documents, is available on the Committee’s website.
Environmental Drivers Study in Clear Lake
The Southern California Coastal Water Research Project (SCCWRP) was contracted by the State Water Resources Control Board and the Central Valley Regional Water Quality Control Board to lead a two-year study (2020-2022) investigating environmental drivers contributing to cyanobacterial blooms and toxin production in Clear Lake, Lake County. The project consisted of developing and implementing a field study monitoring plan and identifying the specific triggers of cyanotoxin production. A total of thirteen lake-wide surveys were conducted in 2020 and 2021 on Clear Lake to compare the biological and physio-chemical parameters that influence the extent, duration, and microcystin concentrations of cyanobacterial blooms. The results of this study will be used to develop recommended approaches to manage and mitigate cyanobacterial blooms in Clear Lake and identify next steps for the Clear Lake Nutrient TMDL.
The final technical report for the study is available on the SCCWRP website or upon request.
Clear Lake Watershed Activities and Resources
Clear Lake is the subject of many programs and activities that are vital to the health and safety of the watershed. The efforts in Clear Lake are not limited to the Clear Lake Nutrient TMDL Program, and the Tribal-led monitoring program, local and State agencies working on water quality issues, and studies conducted on the lake provide more insight into the condition and complexities of Clear Lake.
Clear Lake Cyanobacteria and Cyanotoxins Monitoring Program
- The Big Valley Band of Pomo Indians and Elem Indian Colony began a Cyanobacteria and Cyanotoxin Monitoring Program in Clear Lake in 2014 to address the need for regular and active monitoring in the watershed. The program monitors over twenty sites across Clear Lake for toxins produced by cyanobacteria. To find more information regarding the program, the most recent cyanotoxin monitoring data for Clear Lake, and cyanobacteria impacts to Tribal water uses, please visit the Big Valley Band of Pomo Indians Program web page.
County of Lake Water Resources
- The County of Lake Water Resources is responsible for the preservation, health, and growth of Clear Lake. For more information regarding cyanobacteria, recent harmful algal blooms (HABs), or to report a bloom, please visit the Lake County Clear Lake Cyanobacteria web page.
Clear Lake Drinking Water
- For more information regarding drinking water field operations in Lake County including information regarding the risks of cyanotoxins in drinking water, please visit the State Water Resources Control Boards' Mendocino District website.
Clear Lake Studies
- Under the Blue Ribbon Committee for the Rehabilitation of Clear Lake researchers from UC Davis Center for Regional Change (CRC) and UC Davis Tahoe Environmental Research Center (TERC) are conducting research to guide the Blue Ribbon Committee in improving the environmental quality and economic outcomes for the communities surrounding Clear Lake in Lake County, California. The TERC study is collecting data to understand processes in the Clear Lake watershed that are negatively impacting the rehabilitation of lake water quality and ecosystem health. This data will inform local and State decision-making. Check the UC Davis Clear Lake and TERC Clear Lake Website for more information on the studies.
July 2018 Board Workshop
- Final Agenda - Board workshop to discuss the status and the Board's potential next steps associated with the Clear Lake Nutrient TMDL Control Program. The workshop will include an on-site discussion followed by an afternoon meeting.
- Notice and Tentative Agenda
- Technical Memorandum - An overview of the Clear Lake Nutrient Control Program, the information Central Valley Water Board currently has regarding attainment of load allocations, and recommended next steps for the TMDL.
- Meeting Materials - The materials listed below were provided at the 18 July Board Workshop. In addition, Central Valley Water Board staff have summarized the event in a “Meeting Summary” write-up.
- Meeting Summary
- Central Valley Water Board
- Big Valley Rancheria and Elem Indian Colony
- Middle Creek Restoration Coalition
- Lake County Department of Water Resources
- Lake County Farm Bureau
- Chi Council for the Clear Lake Hitch Letter
- New Central Valley Water Board Outreach and Education Materials
- Clear Lake Watershed Map
- Clear Lake TMDL Allocation Flowchart
- CyanoHAB Trifold
August 2017 Public Outreach
- Notice of Public Outreach Meeting - Concerning the need and options for development of an amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins addressing the Clear Lake Nutrient Control Program.
- Information requested during the meeting about permits, SWAMP and ILRP
- Clear Lake Nutrient TMDL Stakeholders Meeting handout - February 7, 2013
- Clear Lake Nutrient TMDL Update
The Water Quality Control Plan for the Sacramento River and San Joaquin River Basins was amended for a Program of Implementation for Clear Lake Nutrients. A 5-year update to the Clear Lake Nutrient TMDL has been developed to consider information that has been developed and determine whether the phosphorus load and waste load allocations should continue to be required or if some other control strategy or approach is more appropriate.
- Comments Received:
- Essential Public Information Center
- Big Valley Rancheria
- Lake County
- Response to Comments
- Comments Received:
- Harmful cyanobacteria blooms and their toxins in Clear Lake and the Sacramento-San Joaquin Delta (California)
- Final Report - Clear Lake Watershed TMDL Monitoring Program - 2009
- Clear Lake Mercury and Nutrient TMDL's Monitoring and Implementation Plan
- Clear Lake Chlorophyll-a data, MS Excel
- U.S. EPA Approval Letter for the Total Maximum Daily Load (TMDL) to address nutrients in Clear Lake, 21 September 2007
- State Water Resources Control Board resolution approving and amendment to the Water Quality Control Plan for the Central Valley Region to establish a Total Maximum Daily Load (TMDL) for nutrients in Clear Lake, 3 April 2007
- Corrections to the Basin Plan Amendment for the control of nutrients in Clear Lake and Response to Staff Report Comments on 1 February 2007, letter from Central Valley Regional Water Quality Control Board (Pamela C. Creedon, Executive Officer) to State Water Resources Control Board (Tom Howard, Acting Executive Officer)
- Basin Plan Amendment for Control of Nutrients in Clear Lake Adopted by Regional Board on 23 June 2006
- Central Valley Regional Water Quality Control Board Resolution No. R5-2006-0060
- Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Nutrients in Clear Lake, 23 June 2006
- Amendment to the Basin Plan for the Control of Nutrients in Clear Lake
- Response to Comments
- Total Maximum Daily Load for Nutrients in Clear Lake, Lake County, California, 1 December 2004
- Technical Report, by Tetra Tech
Email Subscription List
Subscribe to the TMDL - Clear Lake Nutrient email list to receive notifications and updates.
- Program Contact
- Web page problems: Webmaster5@waterboards.ca.gov
- Report an Environmental Concern
Facts and Information
- Fact Sheets:
- Clear Lake TMDL FAQ
- Lake County Agriculture FAQ
- Clear Lake Algae Blooms FAQ