Discharges from irrigated agriculture are the largest source of pollutionin California’s Central Valley. Water diversions for irrigated agriculture pose significant environmental challenges by diminishing instream flows and depleting aquifers throughout the state. Agricultural operations also pose a significant threat to water quality when nitrates, pesticides, sediment, pathogens, heavy metals, and salts run off fields into surface and groundwater. Farming right up to the riverbank by intensive farming operations has also led to the destruction of natural riparian zones through increased erosion, nutrient and sediment pollution, higher water temperatures, and degraded aquatic habitats.