The Small Watershed Program

Abstract

The avowed purpose of the Department of Agriculture's small watershed program is to conserve water by retaining a maximum amount of it on the land where it falls and to retard agricultural damages caused by run-off in a watershed-the land area which contributes to the flow of a stream. A secondary objective claimed by the Department is to complement mainstream works, such as large dams, levees, and dredged channels, by restricting the flow of water during periods of maximum run-off and reducing sedimentation and excessive siltation of the beds of reservoirs and streams. In short, the Department has visualized this program as a part of flood control as well as a foundation for stabilized agricultural production, especially in areas subject to alternating drought and floods, such as the Missouri basin.1 The program requires two related types of construction-flood-control works and land-treatment measures. The latter (B measures) include such soil-conservation measures as terracing, contour plowing, grade control, and crop management, which have been soil-conservation practices for many years. The flood-prevention structures (A measures) are small wet or dry dams, intended either to create permanent pools or to reduce streamflow during heavy rains, gully-control structures, floodways, bank-protection works, and channel improvements. In order that flood-prevention works may be constructed, the land-treatment measures must be at least fifty per cent completed in a watershed. Although primary emphasis is placed on these two complementary phases of the program (with special need for accelerating landtreatment measures), present legislation also authorizes construction related to municipal and industrial water supply, stream-flow regulation, irrigation, drainage, and agricultural water management.