One of the lessons learned from the devastating 2008 Iowa floods was that current gauging stations do not provide sufficient data for real-time flood forecasting. Traditional stream gauges are expensive — with costly infrastructure, equipment, and maintenance — and it is not feasible to place them on all of Iowa’s many small streams. The Iowa Flood Center’s stream sensor project has helped mitigate this problem with the development of an affordable monitoring system to supplement data from other sources and to collect up-to-the-minute data on Iowa’s numerous streams.
The IFC team, which included students working with professional research engineers, developed an electronic automated sensor that measures stream water height (stage) and transmits this measurement automatically and frequently to a central location.
The sensor is placed on the side of bridges and uses a sonar signal to measure the distance from the water surface to the sensor. The sensor battery is charged with a solar panel and data is transmitted via a cell modem to the IFC website where the data is publicly available. Data from the sensor, and other known parameters at each site, are used to determine stream flow and thus flood stage.
The sensor prototype was deployed on a local bridge in late 2009 for testing. Since then, corrections have been made to the sensor to account for different variables, such as changes in ambient temperature. (Since the speed of sound varies with temperature, we noticed fluctuations in sensor data depending on the air temperature.)
There are more than 2,000 bridges in Iowa that might be used in this new system. Thus, a key element of this project is affordability. We are trying to further reduce costs to maximize the number of new sensors we can deploy.
Enhance Public Safety
The most important benefit of having real-time stream stage data on Iowa’s many streams is an increase in public safety. This system will make it possible to be more precise in determining areas currently affected by flooding, the magnitude of current flooding, and the contribution of different streams to flooding on a larger river. It will also be possible to use the sensors to provide immediate notice to emergency officials when a bridge is impassable due to flooding.
Two students won a elevator pitch competition sponsored by the John Pappajohn Entrepreneurial Center at the UI Tippie College of Business in 2009 for the development of the stream sensors. Read more…