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D R A F T January 4, 2012 comprehensive effort to address salinity problems in the valley and to adopt long-term solutions that will lead to enhanced water quality and economic sustainability. B. Flooding Issue: CALSPA contends that Order No. R5-2007-0113 authorizes the application of biosolids to lands within the 100-year floodplain in violation of federal regulations governing the use of biosolids as a soil amendment. Discussion: The Board concludes that Order No. R5-2007-0113 does not violate the federal regulations, but that the order should be revised to require management practices that prevent biosolids discharges to surface waters. Order No. R5-2007-0113 requires that the use and disposal of biosolids comply with the standards in part 503 in title 40 of the Code of Federal Regulations, governing the use of biosolids as a soil amendment. CALSPA contends that these regulations prohibit the application of biosolids to lands that may be flooded or in such a manner that biosolids may enter surface water or wetlands. While the regulations clearly prohibit application of biosolids to land "that is flooded," the regulations do not directly address the application of biosolids to lands within a floodplain.49 About half of the City's agricultural fields are located within the 100-year floodplain and are not protected from inundation during a 100-year flood event. Winter crops are grown in these areas and may be irrigated with wastewater during the winter. Biosolids, however, are only applied to the corn fields, which are tilled in every year in the fall. Therefore, biosolids that were applied to the agricultural fields during the irrigation season would be incorporated into the soil before the start of the rainy season. In addition, the western agricultural fields are bordered by levees on the west and cannot naturally drain to the Delta. If the levees are overtopped due to flooding, the floodwaters tend to remain onsite until they drain off the agricultural fields through the tailwater system. Order No. R5-2007-0113 requires the City to prepare and implement a wintertime irrigation management plan to minimize water quality impacts during flooding events.50 The management plan must include land application operations and management practices to "minimize or prevent washout of . . . biosolids during 100-year flood events." In State Water Board Order No..2004-0012-DWQ, this Board adopted general waste discharge requirements governing the use of biosolids as a soil amendment. The general order prohibits 49 40 C.F.R. §503.14(b). 50 Order No. R5-2007-0113, VI.C.3.c. 21.