Water Quality Coalition
Dixon/Solano Management Plans Updated 9-27-18
All Management Plans Submittals are posted by the Regional Board. Click on the button for more info.
Representative Surface Water Monitoring Sites within the Dixon/Solano Water Quality Coalition are sampled according to annual monitoring plans approved by the Regional Board. If the same standard is exceeded more than once in a three year period at the same site, a Management Plan is triggered.
COMPLETED MANAGEMENT PLANS
*Nitrate Nitrite as N (Ulatis Creek) - The Regional Board deemed this management plan complete, due to the source evaluation determining the exceedances were from urban sources. Ulatis Creek had Nitrate exceedances at Ulatis Creek on January 18, 2011, December 7, 2011, February 21, 2012, and November 13, 2012. Regional Board deemed this management plan complete in March 2012.
*Malathion Detections (in 2007 only) - Since we have not had any detections since 2007, Regional Board deemed this management plan complete in May 2013.
*Diuron & Associated Algae (Selenastrum) Toxicity (Ulatis Creek) - PRODUCT LIST After intensive outreach in 2010, Ulatis Creek did not have an exceedance during 2010-2011 storm season, for the first time in 6 years. There was one exceedance January 23, 2012. The Coalition conducted a second round of outreach in the fall of 2012 and there were no exceedances during the 2012/2013 storm season. Diuron use in Solano County has decreased substantially over the last five years. Regional Board deemed these management plans complete in July 2016.
*Sediment (Hyalella) Toxicity & Associated Pyrethroid Products in Sediments (Z-Drain) - See PRODUCT LIST. This site had repeated sediment toxicity exceedances and related levels of pyrethroid pesticides in the sediments from 2005-2012. Growers in the Z-Drain watershed spent considerable resources exploring and implementing management practices to address the exceedances and to better understand the sources. Regional Board deemed this management plan complete in August 2017.
IN PROGRESS MANAGEMENT PLANS
*Chlorpyrifos (Shag Slough & Ulatis Creek) - See PRODUCT LIST Ulatis Creek had exceedances for Chlorpyrifos on May 17, 2011, September 20, 2011, March 14, 2012, May 15, 2012 and May 19, 2015. Intensive outreach was conducted in 2011 and 2012 prior to the spring use seasons with reminders sent to alfalfa, grape and walnut growers prior to the spring season. Chlorpyrifos users, potential users and their pest control advisers received updates after the May 2015 exceedance. In July 2015 Chlorpyrifos became a restricted use material. Based on no exceedances since May 2015, Dixon/Solano Coalition submitted a request to deem this management plan complete in September 2018 and it is under review by the Regional Board.
* Algae Toxicity - Selenastrum (Ulatis Creek) Under a related program's monitoring (Delta Regional Monitoring Program) unexplained (no accompanying high levels of herbicides) algal toxicity results were observed at Ulatis Creek in September 2015, February 2016, November 2016. After review of all data, the toxicity exceedances do not appear to be linked with agricultural activities. Dixon/Solano Coalition has added additional monitoring protocols that would be triggered if another algae toxicity is observed at this site, to help identify potential sources. Coalition submitted a request to reconsider the requirement for a management plan in May 2018 and it is under review by the Regional Board.
*Salinity (electrical conductivity, pH), Ecoli, Dissolved Oxygen (There continue to be frequent exceedances for these parameters at all of our sites) - Regional Board put requirements on hold for these Management Plans across the Central Valley as we work to better understand their connection to irrigated agricultural operations.