Suspended matter in several small streams

The measurement of the loads of suspended matter carried past 34 gaging‐stations located on streams in eight regional projects of the Soil Conservation Service has required greater precision in the measurement of discharge and a more intensive program for the collection of samples of suspended matter than has been found necessary by the Geological Survey in making similar measurements on the larger streams on which measurements have been made in the past. It was found early in the work that much the greater part of the annual load of suspended matter was carried in a relatively few days of high water for almost all the streams on which measurements were made. In order that these loads might be determined with reasonable accuracy it was found necessary to collect samples every hour and occasionally every half‐hour on rising and rapidly changing stages during floods. Some floods occurring at night were missed in part or entirely because the resident observer did not realize that a flood was in progress. Twenty‐four‐hour sampling programs, together with the aid of electric‐alarm systems at some stations, have made possible the collection of an adequate number of samples during most floods.