The U.S. Geological Survey operates a network of 170 streamflow-gaging stations in Indiana. The USGS maintains instruments at each station that measure water level (or stage). USGS Hydrographers visit each station every 8 weeks to perform maintenance and measure the streamflow in the stream or river. From the measurements of streamflow, a relation between stage and streamflow can be developed. Then, for each station, stage is recorded; from the recorded stage, streamflow can be computed. With the streamflow gaging-station network, it is possible to monitor the flow conditions across Indiana. Many of the stations transmit near their data so that real-time stage and streamflow data can be accessed through the internet.
Winter poses challenges for USGS hydrographers. Streamflow-gaging stations must still be maintained and streamflow measured. Just getting to a station can be challenging—many stations are several hours driving time from the USGS office in Indianapolis under good conditions, and some are located in remote areas. When hydrographers measure streamflow, they must measure depths and water velocities at 20 to 30 locations across a stream. In the winter, when rivers freeze, they have to cut holes in the ice to measure depths and water velocities, provided conditions are safe. On larger rivers, sophisticated acoustic Doppler flow meters deployed from boats are used to measure streamflow. During the winter, boat measurements can be especially challenging. Boat ramps are often icy; once the boat is in the water, hydrographers may have to dodge floating ice sheets while they make the measurement.
While winter conditions can be daunting around streams and rivers, USGS personnel are prepared. They wear survival suits with built-in flotation while they work near rivers and streams. They have special equipment and gear that allow them to safely cut holes in river ice. They work in teams and follow stringent safety plans. Preparation, knowledge, and training allow the USGS to continue to fulfill its mission of collecting valuable data on Indiana streams and rivers even during the harshest conditions.
For more information about the streamflow gaging program of the USGS visit: http://water.usgs.gov/pubs/circ/circ1123/. Real-time streamflow data from the USGS Indiana streamflow-gaging network can be viewed online at: http://in.waterdata.usgs.gov/nwis/rt.
USGS hydrographer with ice chisel (left) and current meter
mounted on a wading rod (right). The hydrographer has cut holes in stream ice to
measure depths with the wading rod and velocities with the current meter.
USGS hydrographer chops holes in the ice to make a streamflow measurement
USGS hydrographer John Poehler collecting acoustic Doppler flowmeter data on the Wabash River near Terre Haute.
USGS streamflow-gaging station Little Calumet River at Munster, Indiana.
USGS hydrographer making a discharge measurement with a new tethered acoustic flowmeter. The flow data from the flowmeter is transmitted, using radio modem telemetry, to a handheld computer.
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