Abstract |
Infiltration-based green infrastructure and related retrofits for sewershed-level rainfall and stormwater volume capture (e.g., rain gardens, cisterns, etc.) are increasingly being recognized as management options to reduce stormwater volume contribution into combined sewer systems. A hybrid approach with green and grey infrastructures playing to their respective strengths may allow for downsizing or elimination of some ageing grey infrastructure CSO controls. Since CSO activity is typically greater in urban core areas, opportunities to leverage vacant land mass, park land, and other transitional land uses are abundant. However, little is known about urban soils or how these soils may store and transmit water resources. We, therefore, developed an established protocol to characterize soil taxonomic and hydraulic properties and deployed for field studies in Omaha, NE, July 2012. Parcels were selected by City of Omaha wastewater officials in areas where the local sewershed may benefit from additional detention capacity. Urban Omaha, NE, soils ranged in texture from silt-loams to silty clay loams with overall low measured surface infiltration rates. Subsoil permeability was slow, and drainage in the subsurface was limited. A modeling exercise was used to show how field data can be used to approximate GI performance in a large park setting (Fontenelle Park, Omaha, NE) and illustrate how larger land areas may be used to provide sufficient volume capture and capacity to compensate for the limitations of overall slow soil drainage rates. A discussion on how soils can be managed to set the stage for improved hydrologic services and effective land use planning for GI integration into existing wastewater management systems is provided. |