Insights and Challenges in Developing a Remote Real-Time Watershed Mon- itoring Lab

The LabVIEW Enabled Watershed Assessment System (LEWAS) is a remote real-time watershed monitoring lab in Stroubles Creek on Virginia Tech campus. The lab is comprised of an interdisciplinary group of researchers focused on developing an automated watershed monitoring lab with real-time data accessible to a wide range of users on an easy to use platform. Watershed monitoring hardware, including a water quality multiprobe, acoustic doppler flow meter, weather station, outdoor camera, and tipping bucket rain gage, are integrated together using LabVIEW software to provide continuous real-time watershed data. There have been many unique challenges in developing and implementing the remote real time watershed monitoring lab. These challenges include developing routine calibration and maintenance procedures and collecting accurate precipitation and flow data. Collecting accurate and reliable data has required developing calibration and maintenance procedures which prevent errors in data collection and ensure equipment upkeep. To maintain accurate precipitation data, a tipping bucket rain gage was installed at the site to provide additional rainfall data and develop calibration curves for the weather station. Finally, collecting accurate flow data at a unique urban site for all levels of flow has required multiple instruments and flow computation techniques. An acoustic doppler flow meter is installed in a natural run of the stream before it enters a retention facility. A secondary flow measurement is provided by a weir installed in a culvert directly upstream from the outdoor LEWAS site where an ultrasonic transducer measures stage behind the weir. Data from this lab is being used for hydrologic and environmental research in addition to use in multiple courses at Virginia Tech including a senior level Hydrology course as well as freshman level courses at Virginia Western Community College. Introduction The LabVIEW Enabled Watershed Assessment System (LEWAS) is a remote real-time watershed monitoring lab which promotes water sustainability research and educational outreach. The LEWAS field site is located at the watershed outlet of the Webb Branch of Stroubles Creek on Virginia Tech (VT) campus. The watershed is approximately 2.78 km, encompasses portions of the Town of Blacksburg and Virginia Tech campus, and is approximately 95% urbanized. The LEWAS components of water and weather monitoring hardware, sustainable power supply, data collection hardware, and data processing software all work together to provide real-time 24/7 watershed data. The LEWAS functions as an environmental monitoring lab which collects continuous water quality, water flow, and weather data and transmits it in real time to a data server, where it is stored and broadcast to the LEWAS data viewing website. The LEWAS lab is composed of an interdisciplinary team from a variety of backgrounds, who all work together to develop and maintain the lab. There are currently 4 graduate students and 4 undergraduate students working in the lab, and in the past the lab has graduated 3 graduate students (2 MS, 1 PhD) and 6 undergraduate students, and hosted 5 NSF REU students. Students working in the lab have come from a variety of backgrounds including engineering education, electrical engineering, computer engineering, civil engineering, environmental P ge 24761.2 engineering, chemical engineering, biological and systems engineering, biology and chemistry. The LEWAS requires an interdisciplinary team due to the diverse expertise required to design, implement and operate a real-time watershed monitoring lab. Power supply and data acquisition require the expertise of personnel from electrical and computer engineering backgrounds while water quality, flow, and weather studies require personnel with environmental, biological, and civil engineering backgrounds. The LEWAS necessitates synergy among all members to effectively maintain and promote the lab for water education and research. The LEWAS lab equipment includes environmental monitoring sensors and data collection, storage and transmission hardware. A schematic layout of the field site illustrating the location of the sensors and hardware is shown in Figure 1. There are three primary environmental sensors deployed at the site which provide continuous real time data. A Hydrolab MS-5 Sonde collects water quality data including pH, dissolved oxygen (DO), oxidation reduction potential (ORP), turbidity, temperature and specific conductivity. Flow data is provided by a Sontek ArgonautSW Acoustic Doppler Current Profiler (ADCP) which takes stage and index velocity measurements in a stream cross section at the site. A Vaisala Weather Transmitter WXT520 measures air temperature, barometric pressure, relative humidity precipitation and wind speed and direction. In addition, there is a camera installed at a pole near the site which provides supporting visual data of the site conditions. The data from the devices is collected with an embedded computer stored in a control box on site and transmitted through the campus wireless network to a database. Solar panels mounted on a light pole charge two 12 V batteries connected in series, which power the entire system. Figure 1. LEWAS Field Site Layout Data from the LEWAS lab is actively used for water sustainability research and education. Currently there are 3 PhD students and 1 Masters student conducting research in the LEWAS lab with topics covering education, electrical, computer and civil engineering. LEWAS-based P ge 24761.3 classroom modules have also been implemented into a variety of community college and university courses as part of a NSF TUES grant. These include a senior level hydrology course at VT as well as freshman level introduction to engineering courses at Virginia Western Community College (VWCC). In addition to course modules developed as part of this grant, the LEWAS lab has been used in other courses at VT including exposure to over 5,000 freshman in a freshman engineering exploration course), a hydraulics class in civil engineering, and two courses in the geosciences. Pending collaborative proposals also seek to use the LEWAS lab in courses covering geosciences, biology, engineering, and engineering education at VT and other colleges and universities including John Tyler Community College and East Carolina University. Hardware The LEWAS lab equipment includes environmental monitoring sensors, as well as electrical, power supply, and data collection hardware. The entire LEWAS system works together to collect, transmit, store and broadcast live, real-time, high-frequency water quality, flow, and weather data. As illustrated in the LEWAS operational diagram shown in Figure 2, each hardware component serves a critical role in maintaining the function of the lab. Figure 2. The LEWAS Operational Diagram Environmental Monitoring Devices The LEWAS lab currently has three primary watershed monitoring instruments installed at the Webb Branch of Stroubles creek which monitor water quality, flow, and weather parameters. The first is a Hydrolab MS-5 Sonde which measures water quality parameters including pH, temperature, specific conductivity, dissolved oxygen (DO), oxidation reduction potential (ORP) and turbidity. The Sonde is supported by a steel structure mounted to a cement block in the bottom of the stream and protected from debris with a metal casing (Figure 1). The second is a Sontek Argonaut-SW Acoustic Doppler Current Profiler (ADCP) which measures stage and index velocity at a cross section in the center of the stream. The ADCP is mounted to a rectangular concrete block which is secured to the channel bottom and the data cable is encased P ge 24761.4 by metal tubing to prevent damage (Figure 3). Finally, a Vaisala Weather Transmitter WXT520 mounted on a light pole near the site measures air temperature, barometric pressure, relative humidity precipitation and wind speed and direction. Figure 3. ADCP in the stream In addition to the three primary devices, there is also a tipping bucket rain gage which collects precipitation data at the site. However, unlike the other devices, the rain gage is not connected to the LEWAS data flow network through the embedded computer and LabVIEW programming. The rain gage provides supporting precipitation data to reduce any uncertainties in the weather station measurements. There are also plans to expand the field site with additional measurement devices and data collection hardware. An ultrasonic transducer will collect stage measurements in a weir just upstream of the site and will help to provide additional flow measurements to ensure data quality and accuracy. A power monitor will also be installed to track the power consumption of the devices in order to optimize the energy efficiency of the lab. Data Collection Hardware Data from the environmental sensors is collected using an industrial embedded computer (National Instruments CompactRIO) housed in the main control box at the LEWAS site. The CompactRIO runs the real time version of LabVIEW to communicate with the monitoring sensors to collect, analyze, and transmit data. The output from the three watershed monitoring sensors are sent via RS-232 serial links to the National Instruments’ NI 9870 Serial input module, a plug-in module for the CompactRIO 9072 controller. An additional plug-in module, NI 9802, functions as secure removable storage for the collected data and is equipped with two slots for non-volatile memory. A wireless bridge and 14dB directional antenna enable the CompactRIO to establish a wireless connection to the campus wireless network though a point-to-point connection from the LEWAS field site to an access point installed on a nearby campus building. Data is sent through the network to a database located on campus as well as through the LabVIEW web publishing tool to the LEWAS data viewing website. P ge 24761.5 Software A primary goal of the data