Monitoring results are nearing the performance goal exceedance from results collected May 12. Memorial Day weekend typically marks the peak usage for thiobencarb, and subsequently the highest monitoring results.
With favorable weather forecast, there should not be issues with maintaining the waterholding requirements and managing drift over the drains.
All monitoring results have been excellent with the upper Colusa Basin Drain site at the performance goal of 1.5 µg/L on May 12.
Monitoring for 2025 is halfway complete.
The 2025 surface water monitoring under the RPP and WDR programs is ongoing.
For the Rice Pesticide Program (RPP), there have been a handful of detections in late May, none of which were above the agricultural drain performance goal. The latest results from early June were non-detectable.
The Rice Waste Discharge Requirements (WDR) surface water program is in an assessment year, which means additional sampling for pesticides and toxicity.
Pyrethroids used in rice have been reported in association with water toxicity at the upper Colusa Basin Drain this year for multiple events. The California Rice Commission (CRC) sent out letters earlier this year requesting the use reporting information (to be submitted in the fall) for pyrethroid users in the area. Algal water toxicity was reported in the Sacramento Slough near Karnak as well.
The CRC continues to work on behalf of the industry to conduct required monitoring and interface in reporting with the Water Board. Additional efforts are underway to assess and analyze water quality trends across the valley and gather information from industry on uses and operational patterns.
We appreciate the industry’s support of the regulatory programs and their good stewardship of the commercial products used and protection of the environment.
For more information, contact the CRC’s Industry Affairs Manager Craig Riddle at criddle@calrice.org.
May is a critical month for water quality results
Mid-May is the typical 50% plant date for rice in the Sacramento Valley. As such, it is also the month for pre-emergence pesticide application and thus a critical time for water quality results.
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Water Quality Is Our Collective Stewardship
The water quality monitoring under the Rice Pesticide Program (RPP) will begin on April 29th. The RPP monitors for thiobencarb for 10 consecutive weeks at 4 agricultural drain sites and one site in the Sacramento River near downtown Sacramento.
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