Native Soil & Groundwater
Native soil characteristics determine the types of facilities that are possible, as well as the required intensity of the design. Capitalize on high-quality soils for their infiltration capacity.
Analyze the soil’s infiltration rate. Gravelly and sandy soils infiltrate water more quickly than clay. In areas with slow infiltration or poor soil quality, GSI can be designed with an underdrain.
Test soil for contamination from previous projects, especially at industrial sites.
Investigate the depth to the groundwater table. In areas with a shallow groundwater table or seasonal high water table, use non-infiltration stormwater facilities to prevent pollutants from reaching the water table.
Consider the location of existing gray stormwater infrastructure, especially drainage grates and catch basins.
Consider the location of subsurface transit infrastructure, utilities, and sleeves to avoid conflicts with stormwater projects.
Take stock of adjacent buildings with basements or subsurface structures. Stormwater facilities may require liners or deeper walls to prevent lateral water seepage into basements.
Consider other structures in the right-of-way such as transit stops, utility poles, mature trees, benches, wayfinding signs, or other street furniture. Maintain ADA access around doors and access routes.
Identify opportunities for synergy, especially with adjacent redevelopment or property owners interested in beautification or flood mitigation.