8 CAR § 110-713
Any solid waste facility, located either partially or wholly within the Benton County Regional Solid Waste Management District, which is required to maintain a stormwater retention basin by either Division of Environmental Quality or federal standards, particularly 40 C.F.R. § 258.26, shall build any such stormwater retention basin or basins to retain all stormwater generated by a twenty-four-hour, hundred-year rainfall event.