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
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.
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.
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List of common pyrethroids, click here.
Solano Spray Safe 2025 Presentations (February 19, 2025)
Pyrethroid Water Column Exceedance December 17, 2024 - Notice to Members
Materials from August 2025 - Grower Meeting
Material and recording of the meeting will be posted here after the meeting.
Pyrethroid Exceedance Grower Meeting
Wednesday, August 13, 2025 at 10:30 am to 11:30 am
D/S RCD Conference Room
1170 N. Lincoln Street, Suite 109
Dixon, CA 95620
Online option:
Join Zoom Meeting
https://us02web.zoom.us/j/85954149900?pwd=lQJdD5aBYlH8mOi1T749yP6UwVPaHY.1
Meeting ID: 859 5414 9900 Passcode: 295772
Dial by your location • +1 669 444 9171 US
Questions? Martha McKeen 707-678-1655 x103
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
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.