Description: Capacity-constrained is defined by the Stormwater Code, SMC 22.801.040 as a drainage system that the Director of SPU has determined to have inadequate capacity to carry drainage water.There are three distinct areas that compromise what is currently mapped as capacity-constrained, 1) the entire network comprising the informal drainage system consisting of the intermittent ditch and culvert network as these were never engineered, they are inherently capacity constrained. 2) The infrastructure contained in the Densmore Basin which discharges to a King County storm drain which was not designed with capacity to convey runoff from the increased density from additional development. 3) a portion of the public storm drain system on Capitol Hill upstream from the maintenance hole at the intersection of Pike St & Melrose Ave, there is a hydraulic restriction in this maintenance hole which leads to an extremely elevated hydraulic grade line and associated localized surface flooding.For more information on this Code please see, http://water.epa.gov/polwaste/nps/upload/nps-ordinanceuments-seattle-code.pdf
Copyright Text: City of Seattle, Seattle Public Utilities