Description: The site contains two drainable limestone beds (DLBs) that use limestone aggregate to neutralize acidity, raise pH and add alkalinity. Each DLB treats a separate source of AMD. The North Culvert DLB treats AMD captured from a drainage channel using a Coanda intake screen mounted on a concrete intake weir structure. The Pit Spring DLB treats AMD collected in a French drain located just south of the North Culvert DLB. Primary effluent from each system flows back to the drainage from which it was collected. The DLBs are automatically flushed by draining them empty once/week when independent solar-powered computer-controlled gate values are activated. Flush effluent is directed to a dedicated flush pond that serves both DLBs.