Water Quality

Rice Water Quality Programs Monitoring Summary

Rice Water Quality Programs Monitoring Summary

Monitoring for 2025 is complete.

The 2025 surface and groundwater monitoring under the RPP and WDR programs was completed by August.

For the Rice Pesticide Program (RPP), no detections of thiobencarb were reported above the agricultural drain performance goal.  We anticipate that treated acres were closer to the historical average this year; last year saw a significant decline in treated acres versus planted acres.  We thank the product manufacturers and the County Agricultural Commissioner’s offices for their support of the program.  

The Rice Waste Discharge Requirements (WDR) surface water program monitored benzobicyclon and bispyribac-sodium, with generally good results.  The pyrethroid monitoring results reported toxicity and acute pyrethroid triggers in several samples at the upper Colusa Basin Drain (CBD5) and Sacramento Slough (SSB).  Failure to meet the pyrethroid monitoring objectives at CBD5 and SSB could result in further potential measures to gain compliance, such as expanded monitoring, NOIs before applications, increased inspections, limited acreage application, or, in extreme cases, expulsion of farms from the coalition that are in gross violation of label requirements and Rice WDR conditions.

The Rice Waste Discharge Requirements (WDR) groundwater program reported low levels (consistent with historical averages) of nitrates in shallow groundwater beneath rice fields.  These results continue to support our Nitrate and Initial Assessment and Technical Memo(s) that have demonstrated a de minimis impact of nitrate leaching from rice fields into shallow groundwater.

We appreciate the industry’s support of regulatory programs and its good stewardship of commercial products, as well as its protection of the environment.

For more information, contact the CRC’s Industry Affairs Manager Craig Riddle at criddle@calrice.org 

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Rice Water Quality Programs Monitoring Update

Rice Water Quality Programs Monitoring Update

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.