Why is the King County project team not evaluating an upper basin alternative for the Murray basin?
Locations higher in the basin were examined, but they could not capture enough peak flow to meet CSO control requirements. The existing system brings flows together within two blocks of Lowman Beach Park, making the bottom of the basin the only location to capture an adequate quantity of the peak flow to meet compliance requirements. In addition, we evaluated ways to reduce peak flow by separating stormwater from the combined system and rerouting it to a new or existing storm drainage system. We also considered flow reduction through green stormwater infrastructure measures (rain gardens and bioswales). Unfortunately, these methods would not be able to control the one million gallons needed in the Murray basin, and storage would still be required at the bottom of the basin to meet the overall control requirement.