Memorandum Opinion and Order

This case involves a challenge to the Environmental Protection Agency's (the EPA's) decision, pursuant to its authority under section 303(c) of the Clean Water Act, 33 U.S.C. § 1313(c), to approve the State of West Virginia's antidegradation implementation procedures, a set of procedures designed to prevent the degradation of the State's waters. For the reasons that follow, the court concludes that lhe EPA acted arbitrarily and capriciously in approving West Virginia's antidegradation procedures. With respect to seven particular aspects of West Virginia's program, the EPA failed to ensure that West Virginia's procedures met minimum federal requirements, as defined by the Clean Water Act and the EPA' s own regulations. In some instances there is simply insufficient evidence in the administrative record to support certain aspects of West Virginia's implementation procedures and, correspondingly, the EPA's approval of those procedures. For example, West Virginia has classified the main segments of the Kanawha and Monongahela Rivers as Tier 1 waters, but there is ahnost no evidence in the record about the water quality of these rivers that would justify the decision to deny them the more stringent protection of Tier 2. See infra at IV .1. Nor is there sufficient evidence in the record explaining how Tier 2 review, which is locationspecific and requires public participation, could be done at the time a general section 402 or section 404 permit was issued, rather than at the time new individual discharges are proposed. See infra at IV.4. In other instances, West Virginia's regulations simply fail to require the minimum protections required by the EPA' s regulations, and the EPA' s approval of West Virginia's procedures was based on an unreasonable attempt to eftectively amend the plain meaning of those provisions so as to bring them into line with federal requirements. For example, West Virginia's procedures allow new or expanded discharges from certain wastewater treatment plants to evade Tier 2 review if the new discharge results in a "net decrease in the overall pollutant loading." The EPA approved this provision as consistent with minimum federal standards by, in effect, amending it to apply only when there is a net decrease in the pollutant loading for each pollutant parameter. See infra at IV .3.