Innovative strategies reduce selenium in Grasslands drainage

Abstract

The Grasslands Bypass Project in the western San Joaquin Valley of California was conceived as a means of diverting selenium-contaminated agricultural drainage water from fresh water channels serving Grassland wetlands. Use of the federally owned San Luis Drain was made contingent on the formation of a regional drainage management authority by the project proponents and compliance with strict monthly and annual selenium-load targets and agreement to strict monthly and annual selenium-load targets for discharges from the 97,000-acre (44,000 hectares) project area. During the first year of this 5-year project, the Grasslands Basin farmers were successful in reducing selenium export from the project area by 44% and 33% when compared to water years 1995 and 1996. Although monthly targets were exceeded during the spring months of 1997, in part due to unusually high rainfall runoff from the project area and upper watershed, the goals of the project were met. There is popular sentiment that more was learned about selenium drainage management and achieved in selenium load reductions by participating water districts during the first year of the project than in the past decade.