Measuring waterThis page of the Water Science Picture Gallery contains images of how water information is collected by the U.S. Geological Survey (USGS). There's a tremendous amount of field work that has to be done to develop and maintain a nationwide system of water-data sampling. Surface-water sampling methods and equipment:Stream gage on a bridgeMaking a stream-discharge measurement from a bridge Taking a water sample from a bridge Sampling a small stream A quick way to measure high water Sampling a lake bottom Automatic stream sampler to collect water samples Shocking fish to collect biological samples Laboratory equipment and procedures:pH meter to measure acidity |