Data from channel-change monitoring at selected sites in Maricopa County, Arizona, 1997-2002

Stream channels in arid regions are subject to a wide range of hydrologic, hydraulic, and sedimentary conditions. These channels often are dry or have little streamflow most of the time, and the few flows that do occur can cause substantial changes to the channel and flood plain. Because floods in arid regions are often flashy, and many gaging stations are in remote areas, hydrographers must rely on indirect measurements of streamflow. Channel change is important because one major assumption necessary for indirect measurements of discharge is that the channel conditions after the flood represent the conditions during the peak discharge.

The U.S. Geological Survey, in cooperation with the Flood Control District of Maricopa County, is monitoring selected perennial and ephemeral streams within Maricopa County, Arizona, to track the amount and variability of channel change. This report contains basic data from surveys of monumented cross sections conducted from 1997 through 2002. The amount of change varied widely from channel to channel, and the largest geomorphic change occurred in conjunction with peak flows above the 10-year recurrence interval.