Sewerage and Water Board of New Orleans Administration Building: Stormwater Green Roof Project 625 St. Joseph Street. Evans + Lighter Landscape Architecture, working with Hanging Gardens LLC, designed and installed one of the largest state-of-the-art green roofs in the southeastern United States on the downtown administration building of the Sewerage and Water Board of New Orleans. The living roof features four unique zones of vegetation and engineered soils including a biomimetic wetland roof, Cajun prairie, and traditional sedum roof. The roof was designed to enhance habitat, disperse native seed, and provide ecological services to the building, including stormwater mitigation in excess of 15,000 gal per rain event.