Robert Léger on SLOPES V Water Quality Compliance

Robert LegerAfter a month off, the EWRG community came out in full force for the May presentation. Robert presented on SLOPES V compliance a federal permitting process regulated by the Army Corps and the National Marine Fisheries Service, which is essentially a shortcut to meeting the Endangered Species Act. His presentation lead to excellent conversation and discussion. See attached for Robert’s presentation.

Robert’s presentation explained his methodology of meeting the water quality flow requirement for SLOPES V, which states a facility must “…accept and fully treat the volume of water equal to 50% of the cumulative rainfall from the 2-year, 24-hour storm for that site…”

Robert posited that the City of Portland (COP) and Clean Water Services (CWS) water quality standards already meet this requirement, and went about showing this to be so depending on facility design.

Breaking apart a Type-1A hydrograph, Robert did a volume analysis and determined that a water quality facility designed to meet COP standards treats 90% of the 2-year event, while a CWS facility treats 74% of the 2-year event (for the projects he presented on see attachment). The facilities that he designed to meet local requirements required no expansion or increase in capacity to meet the Federal requirements.

He has received positive feedback from the National Marine Fisheries Service.