Dixon/Solano Management Plans

Update on Dixon/Solano Management Plans Updated 11-11-16


*Nitrate Nitrite as N (Ulatis Creek) - The Regional Board has deemed this management plan complete, due to the source evaluation determining the these 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) PRODUCT LIST below This site had recurring sediment toxicity exceedances and related levels of pyrethroid pesticides in the sediments.  Growers in the Z-Drain watershed have spent considerable resources exploring management practices to address the exceedances and we are still working on source identification as well as management practice effectiveness.  Regional Board is reviewing a request for completion for this management plan 

*Chlorpyrifos (Shag Slough & Ulatis Creek) PRODUCT LIST below  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.  We continue to work with members to implement practices to address this issue.

*Salinity (electrical conductivity, pH) , Ecoli, Dissolved Oxygen (at all of our sites) - Management Plans requirements have all been suspended until Sac Valley Waste Discharge Requirements Order is adopted in early 2014.

Kelly Huff,
Nov 11, 2016, 2:56 PM