Ulatis Sediment Toxicity
Our Current Management Plan: Ulatis Creek Sediment Toxicity Management Plan*
History of Ulatis Creek/brown Road Monitoring Site
Sediment Toxicity Exceedances
- April 17, 2018 - Lambda-Cyhalothrin
- April 18, 2019 - Lambda-Cyhalothrin, Bifenthrin
- April 21, 2022 - DNQ (Detected, not quantified
- *April 16, 2025 - DNQ (Detected, unknown pyrethroid)
Water Column detections
- August 21, 2018 - Lambda-Cyhalothrin
- March 19, 2019 - Lambda-Cyhalothrin
Water Column exceedances
- June 23, 2021 - Lambda-Cyhalothrin
- December 17, 2024 - Bifenthrin, Lambda-Cyhalothrin, Cyfluthrin, Esfenvalerate
- May 20, 2025 - Bifenthrin
*Sediment Toxicity Management Plan (MP) with Water Column addendum, extended 3 years until 2028
Ulatis Crk_Hyalella Toxicity_Mgmt Plan Addendum_20251113_clean.pdfUCBRD_pyrethSQMP_signed (1).pdfMap of the Management Plan Boundaries for the Cache Slough Represented Drainages
We had zero sediment toxicity exceedances (or detections) in 2023 and 2024 thanks to collective efforts to use BMP (best management practices) when applying pyrethroids. Growers are also using alternative pest control products or techniques such as biological control, habitat manipulation, and cultural practice changes to reduce the need to apply pyrethroids.
Note: The exceedances in December 2024 and May 2025 have triggered an additional management plan. The Regional Board approved an addendum to be included in the current sediment toxicity management plan. This was approved on January 9, 2026.
Note: The exceedances in December 2024 and May 2025 have triggered an additional management plan. The Regional Board approved an addendum to be included in the current sediment toxicity management plan. This was approved on January 9, 2026.
Sediment Toxicity Management Plan Focus
Monitoring Site: Ulatis Creek at Brown Road
Crops: Alfalfa and Tomato, processing
Pesticides: Pyrethroids: Lambda-Cyhalothrin, Bifenthrin
Our Goal: Zero exceedances
- List of common pyrethroids, click here.
- BMP for Pyrethroids
Solano Spray Safe 2025 Presentations (February 19, 2025)
Solano Spray Safe 2025 Presentations (February 19, 2025)
Water Quality and Pesticides, Martha McKeen, Dixon RCDPyrethroid Water Column Exceedance December 17, 2024 - Notice to Members
Materials from August 2025 - Grower Meeting
Presentation from October 2021 - Grower Meeting
101921 Grower Meeting.pdfPresentation from October 2019 - Grower Meeting
10_17_19_Grower Meeting Materials.pdfSediment toxicity exceedances were observed in April 2018 and April 2019 at the Ulatis Creek Site with accompanying levels of pyrethroid pesticide products detected in the sediments. Although pyrethroid pesticides are utilized throughout the year for both urban and agricultural land uses, initial outreach has focused on alfalfa and tomato growers because of the timing of the exceedances.
Sediment toxicity exceedances were observed in April 2018 and April 2019 at the Ulatis Creek Site with accompanying levels of pyrethroid pesticide products detected in the sediments. Although pyrethroid pesticides are utilized throughout the year for both urban and agricultural land uses, initial outreach has focused on alfalfa and tomato growers because of the timing of the exceedances.
‘Sheeping off’ PracticePolyacrylamide