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Vantage to Pomona Heights Chapter 3 230 kV Transmission Line Project FEIS Affected Environment PAGE 3-284 past 150 years, people have depended on the aquifers for their domestic and stock water. Up until fairly recently, the well construction techniques and health and safety protections in place on those wells were fairly rudimentary. People have often utilized the first available water resource for their water supply. The shallowest aquifers in the valleys are reported to have been contaminated by bacteria and nitrates and chemicals for much of that time (Dispute Resolution Center of Yakima and Kittitas Counties 2010). Existing studies and related water quality data indicate that nitrate contamination of groundwater exist in the region and at least portions of the Project study area. In some areas, nitrate levels are in excess of the state drinking water maximum contaminant level (MCL) of 10 milligrams per liter (Washington State Department of Agriculture et al. 2009). Under Section 1431 of the Safe Drinking Water Act, the USEPA has broad authority to take action where there is a contaminant in an underground source of drinking water that may present an imminent and substantial endangerment to the health of persons. The USEPA has determined that these conditions exist in the Yakima Valley because nitrate levels are above the MCLs. JBLM YTC also utilizes non-potable water from both ground and surface water sources for fire suppression activities. Fire suppression well water resources within the Project study area include developed and undeveloped well/water points (JBLM YTC 2002). Critical Aquifer Recharge Areas Critical aquifer recharge areas are areas designated by Washington Administrative Code (WAC) 365-190- 100 that are determined to have a critical recharging effect on aquifers (i.e., maintain the quality and quantity of water) used for potable water as defined by WAC 364-190-030(3) (Kittitas County 2014). According to WAC 365-190-100, critical aquifer recharge areas include: recharge areas for sole source aquifers designated pursuant of the Safe Drinking Water Act; areas established for special protection pursuant to a groundwater management program; areas designated for wellhead protection pursuant to the Safe Drinking Water Act; areas near marine waters where aquifers may be subject to saltwater intrusion; and other areas meeting the definition of “areas with a critical recharging effect on aquifers used for potable water” (Washington State Legislature 2015). Counties and cities must classify recharge areas for aquifers according to the aquifer vulnerability. Vulnerability is the combined effect of hydrogeological susceptibility to contamination and the contamination loading potential. High vulnerability is indicated by land uses that contribute directly or indirectly to contamination that may degrade groundwater and by hydrogeologic conditions that facilitate degradation. Low vulnerability is indicated by land uses that do not contribute contaminants that will degrade groundwater and by hydrogeologic conditions that do not facilitate degradation. Hydrological conditions may include those induced by limited recharge of an aquifer (Washington State Legislature 2015). Benton County defines critical recharge areas as those where surface waters have connectivity to an underlying aquifer. Maps of the critical recharge aquifer areas in Benton County are not currently available; however, aquifer protection areas identified with suspected surface/groundwater connectivity include: areas within the riverine corridor; floodplain and wetlands; areas of known surface hydrology per information gather by the Benton Franklin Health District; and areas along the unlined main canals of local irrigation districts (Benton County 2006). Grant County classifies critical recharge areas as: areas designated as wellhead protection areas pursuant to WAC 246-290-135(4) and the groundwater contribution area in WAC 246-291-100 (2)(e) including the identified recharge areas associated with either Group A public water supply wells and those Group B wells with a wellhead protection plan filed with the Grant County Health District; and any land identified