Tolessa Deksissa
To restore and sustain urban stream or river water quality, many cities have been devoting to a green infrastructure, and federal agencies have started collaborating to help the community invest in green roof, roadside rain gardens and increased tree canopies. The objective ofthis study is toanalyze the ecosystem benefit of the green stromwaterinfrastructurethat applies to managing stormwaterquantity and quality.Using an ArcGIS-based modelling tool, we quantitatively analyzedthe ecosystem service of green roofs. The results show that constructing green roofs on the rooftops of 2% of the impervious areas or building can reduce up to 166% and 32% storm water runoff in Rock Creek and Anacostia River sub-watersheds in Washington DC, respectively. This can save up to $21.4 million in building storage tanks to store total runoff volume. Improving green roof and tree canopy areas can significantly reduce the negative impact of urban storm water runoff and therebyimprove urban-stream water quality