In response to increasing water quality concerns related to potential microbial contaminants, the Washington Aqueduct Division (WAD) of the Corps of Engineers retained O’Brien & Gere to develop a site-specific Operations and Maintenance (O&M) Manual for the 240 MGD Dalecarlia Water Treatment Plant (WTP) in Washington, D.C. The Dalecarlia WTP, which is owned and operated by the Corps of Engineers, had recently experienced a widely publicized, high-turbidity event due to an operational problem, and therefore the Corps of Engineers elected to document and standardize the operations of the plant to facilitate optimal operations which would thereby minimize potential for waterborne disease outbreaks. The Manual is intended to serve as a reference tool for operator training and to enable standardization of operations.