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 Extended 3 Years Until 2028

Learn more here

Map 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: Water column exceedances have not been included into the current management plan at this point. Due to the May 2025 water column exceedance, this may cause an addendum to the current sediment toxicity management plan. This decision to be determined by the Regional Board. 

Ulatis Creek at Brown Road Sediment Toxicity Management Written Plan

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 sediment toxicity exceedances in 2025 to complete the current management plan and beyond.

• List of common pyrethroids, click here.
• BMP for Pyrethroids

Solano Spray Safe 2025 Presentations (February 19, 2025)

Water Quality and Pesticides, Martha McKeen, Dixon RCDPyrethroids in Processing Tomatoes, Patricia Lazicki, UCCE

Pyrethroid Water Column Exceedance December 17, 2024 - Notice to Members

Materials from August 2025  -  Grower Meeting

Materials from October 2021  -  Grower Meeting        

This video is a result of a water quality monitoring exceedance at the Ulatis Creek monitoring site on June 23, 2021.

This video covers pyrethroid pesticide application primarily on orchards.

Original meeting date: October 19, 2021

Video duration: Approx. 1 hour

101921 Grower Meeting.pdf

Materials from October 2019  -  Grower Meeting        

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’ PracticePolyacrylamideUlatis Creek Sediment Toxicity Management Plan Meeting