Stanford University graduate student Peter DeMarco partnered with CWC to complete a new report, “Dairies’ Risk to the Drinking Water of Disadvantaged Unincorporated Communities in the Tulare Lake Basin." We presented our findings at the Regional Water Board meeting in December, and the Board followed up at its February meeting. Pete used GIS data mapping to identify dairies within 1.5 miles of the borders of disadvantaged unincorporated communities (DUCs) in Fresno, Kern, Kings, Madera and Tulare Counties and collected information on nitrate levels on dairy facilities and in on-farm wells, as well as dairies with General Order violations.
We found that 106 active dairies are located in a high-risk zone around 45 low-income, unincorporated communities in Fresno, Kern, Kings, Madera, and Tulare Counties. Fifteen dairies’ application of nitrogen exceeded the General Order’s maximum nitrogen budget limit, and eight dairies applied nitrogen at rates that presented serious risk to surface or groundwater contamination. Additionally, a total of 65 dairies are located within vulnerable groundwater environments, have reported on-farm well exceedances, or both.
Based on these findings, we recommend that the Regional Board strengthen existing regulations to control nitrate leaching, particularly in dairies near high-risk communities.