Surface Irrigation Systems That Deliver Bacteria to Vegetable Crops

Malheur County, Oregon has a surface irrigation canal systems dating from early in the 20^th century.  The county is also a leading producer of beef and onions.  The FDA is proposing to adopt the EPA's primary contact recreational water standard (235 colony-forming units (CFU) E. coli/100ml and 126 CFU E. coli/100ml on a 5-sample geometric rolling mean) for vegetable crop production. In Malheur County, surface irrigation water delivery systems maximize scarce water by reusing runoff water from other growers. Agricultural drain water is mixed with relatively clean project water to provide ample supply to all growers.  Agricultural drain water in runoff reuse systems enhances the amount of water available. However, it carries high microbiological contaminant loads picked up from each user, including from enclosed livestock, small mammals and birds that live and feed in agricultural fields, and waterfowl and birds that live and feed in agricultural wetlands. It can be demonstrated that runoff water for reuse cannot meet FDA's proposed rule for agricultural water.  Options for producers will be discussed.