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Show i FLOOD CONTROL I" i When rainfall or winter thaws supply water faster ' than it can be absorbed and more rapidly than streams can " carry it away, floods result. To date man has had little or t no direct influence on the amount of water which may fall j on a given area. However, by unintelligent treatment of cover and of soil, man has induced, through the medium of v running water, changes in this delicately balanced combi-V combi-V nation of materials which range from small losses to com-l com-l plete devastation. 4 In general, man's use of the soil has resulted in more rapid running off. In regions where the rate of run-off has S been accelerated, flood conditions are critical during times of excessive precipitation, cfc; Direct flood control work such as dike and levee con-:eui con-:eui struction does little toward permanent control. In most "f- cases such work creates a more serious flood condition be-to be-to cause river bottoms are raised by successive lesees until "nt they actually stand higher than adjacent lands. Control of floods is a problem not usually attacked di-reclty di-reclty by SCS projects. Indirectly, however, the work of this service ranks high in lessening flood danger by reduc-y reduc-y ing both the amount and rate of run-off. This is brought about by work directed along the following lines : grass U'i and legume plantings, fire protection at many location points within a given watershed, tree planting, contour trenching, reservoir sites, water spreading, and water hole development. These are great and fundamental aids to nature in the all-important task of bringing about water penetration in place of run-off. Water entering soil feeds plants and supplies the ground water tahle, which in turn is the principal source of streams and springs into which j it makes its way steadily by clear, cool seepages. Streams ' thus fed present ideal conditions for fish, for power, and 'ifor navigation. "" Run-off on lands where water and soil conservation are not practiced often gains sufficient momentum to rush away 2a as roaring floods; wasting soil, destroying plant food, dig-Em dig-Em ging gullies through fertile fields, overwhelming and burying the lowlands, filling reservoirs, washing out dams and i clogging harbors. n |