September 2009 Flooding
Crooked Creek at Norcross (02335350)

Georgia Water Science Center hydrographers manually measuring streamflow. The crane holds a heavy weight and a "current meter", which has vanes that spin in the water current. The scientist counts the spins to measure a velocity reading of the water. By doing this at a number of points both vertically and horizontally across the stream, a "discharge measurement" is completed that gives the streamflow, which is the amount, in cubic feet per second, of water flowing at the time of measurement. The streamflow is measured at the current "gage height", which is the height, in feet, of the stream above a certain point.

Georgia Water Science Center hydrologists measuring the stage of the water. The metal box holds a wire attached to a weight, which is used to make a quick measurement of stream stage, or gage height. The scientist lowers a weight from the box until the bottom of the weight just touches the water to make a measurement.