Ballard Development: SPU proposes Ballard NDS 2015 SEPA Determination of Non-Significance
The Ballard NDS 2015 Project would design and construct infiltrating raingardens (bioretention cells) along up to 22 city blocks. Those raingardens would be located primarily in existing planting strip areas within City street rights-of-way. Existing planting strips would be converted from landscaped, lawn, or impervious areas to vegetated bioretention cells and upland planting areas.
The raingardens would be designed to receive stormwater that currently flows in roadway gutters to combined sewer inlets. The raingardens would include bioretention soil to provide water quality treatment. Inlet curb cuts would be installed to route stormwater flow from the roadway gutter to the raingardens. Outlet curb cuts would be installed on the downstream end of the raingardens to allow conveyance of excess flows (during high flow events) via roadway gutter to the nearest down-gradient existing combined sewer inlet.