Meteorologic and physiographic factors in parts of Texas combine to produce some of the most intense rainstorms in the Nation; these rainstorms cause severe, destructive floods somewhere in the State almost every year. A recent example is the catastrophic flooding in the Houston area in October 1994 that resulted in at least 22 deaths, hundreds of millions of dollars in property damage, and substantial environmental damage. When flooding is imminent, the U.S. Geological Survey (USGS) mobilizes field crews that work around the clock making direct measurements of streamflow and water-surface elevations. The data collected by USGS personnel are provided continuously to the National Weather Service and the Federal Emergency Management Agency among others. The data collected during a series of floods provide a chronology of historical peak streamflows and water-surface elevations that aid in flood forecasting and the design of structures to convey or withstand flood waters.