Description
Heavy rainfall can overwhelm leachate and contaminated stormwater storage and conveyance systems at landfills and transfer stations. To help adapt to projected increases in heavy rain and reduce the likelihood of system overflows, King County will implement smart controls to monitor and manage leachate and contaminated stormwater at the Cedar Hills Regional Landfill and relevant closed landfills, creating greater resilience to the impacts of extreme precipitation. Work on this action includes installing sensors that monitor reservoir levels and incorporate weather forecasts to allow real-time monitoring and support storage optimization.
King County will also assess current designs for stormwater conveyance and storage at Cedar Hills, closed landfills, and transfer stations, and implement approaches that reduce runoff from extreme precipitation events. This includes retrofitting or updating designs to account for current and projected increases in stormwater volume. Steps taken as part of this work will help reduce stormwater runoff, reduce peak flows and pollutant loads downstream, and reduce the risk of erosion and flooding at or near the landfills.