Wednesday, August 9, 2017: 4:00 PM
Portland Blrm 256, Oregon Convention Center
We have installed wireless sensor networks to monitor a number of green roof and plant-based stormwater control systems in Washington, DC – both federal and private, during the past three years. Many green roof systems have been installed using Leadership in Energy and Environmental Design (LEED) principles, and yet most are not monitored in any way, to allow for assessment of continued stormwater performance. We will describe and discuss two projects at the US Tax Court and at the US Botanic Garden, which provide insight into stormwater runoff and performance from urban stormwater mitigation structures. The sites are monitored using wireless sensor networks, with both environmental (weather station) sensors, soil moisture sensors, flow meters and drain gauge (pressure transducer) devices. Data are logged using EM50R radio dataloggers (Decagon Devices, Inc) on a 5-minute basis, and transmitted to a computer and radio basestation on site. Data are then assimilated into a database and charted graphically using Sensorweb software (Mayim, LLC). Real-time data are made available over the internet through a password-protected site.
Results/Conclusions: The sensor data provide an accounting of rainfall and irrigation inputs, daily reference evapotranspiration (ETo), estimated daily crop water use (ETc) from soil moisture (Kc) data and verification via measuring runoff when it occured. The Sensorweb software not only allows real-time access to the data, but also for model-based analysis of the data. Data from 97 storm events from April, 2015 through October, 2016 will be presented. The implications of this work will be discussed in the context of measuring green roof performance for reducing impervious surface fees and the trading of stormwater credits.