Water Resources Research Act Program

Details for Project ID 2015MD326B

Water balance of a green roof integrated with a constructed wetland and rain garden for urban water management

Institute: Maryland
Year Established: 2015 Start Date: 2015-04-01 End Date: 2016-02-29
Total Federal Funds: $24,744 Total Non-Federal Funds: $50,110

Principal Investigators: David Tilley

Project Summary: Several local and state governments have implemented financial rebates and tax credits for land owners that install green infrastructure to manage stormwater. A major impetus is to reduce the flow of stormwater from urban areas into receiving waters. However, a complete understanding of how design characteristics of living technologies affect storm runoff and water balance is lacking, especially for green roofs. Horizontal, extensive green roofs are known to reduce peak runoff amounts during rain events, but little is know about sloped green roofs. As the desire to install green roofs expands beyond roofs with little slope to those with steeper slopes, often found on residential homes, there is a need to understand how slope affects runoff. WaterShed, the University of Maryland’s winning entry in the 2011 U.S. Department of Energy Solar Decathlon competition, has been converted to a long-term research and education facility where applied research, like runoff analyses can be completed, while promoting and demonstrating environmental sustainability. Instrumentation installed on the roof and connected living technologies will allow high-resolution data analysis of rain events. The research will determine the water balance (rate of runoff, evapotranspiration) for various-sized storm events throughout the year for the sloped roof. Runoff and ET will be related to soil moisture, plant cover and leaf area index. The research will provide critical knowledge about how sloped green roofs affect the water balance, especially storm runoff, of built structures. Regulatory agencies will find this information useful as they implement and modify policies that encourage green infrastructure for stormwater management.