Laserfiche WebLink
<br /> <br />001526 <br /> <br />LOSSES OF CAPACITY <br /> <br />Sedimentation <br /> <br />Control of sedimentation in stock ponds can generally be achieved <br />by good range management, which is a composite of num'erous actions. <br />Good stock pond sites are scarce and valuable enough to be class ed as <br />a resource and treated as such. <br /> <br />One observer has said: <br /> <br />"Practical understanding of the physical basis of the <br />present-day silt problem requires first of all, a definite <br />recognition of the dependence of silting upon erosion of <br />directly tributary watershed areas and of the critical fact <br />that rates of erosion are neither uniform nor fixed in dif- <br />ferent sections of the country, but are subject to material <br />changes under a civilized use and abuse of lands and var- <br />ious practical measures of erosion control. This is all <br />too frequently a difficult advance on the part of scientists <br />and engineers who have studied erosion only from the view- <br />point of primordial forces and process of nature." (Eakin, 1936) <br /> <br />Caus es and control of sedimentation should be considered before <br />stock ponds are constructed. The primary measures to slow down sedi- <br />mentation are: prevention of overgrazing, maintenance of good vegeta- <br />tive cover, proper season of use, settling basins and check dams, fencing <br />of protective areas, fire protection, and an adequate number of well-placed <br />stock ponds. <br /> <br />The principal sediment sources of interest to this study are: <br />s h ee t eros ion, as caus ed by wind and su rface runoff by overland flow <br />without the formation of distinct channels; gullying, or the cutting of <br />deep and/ or wide channels by concentrated runoff, and eros ion from road <br />fills and cuts, mining and mineral exploration. <br /> <br />Overgrazing by both wildlife and livestock contributes to sedimen- <br />tation of stock ponds. Overgrazing also encourages valley trenching, <br />gullies, and surface wash, which contribute to the rapid depletion of <br />stock pond storage capacity. Location of stock ponds in areas with slopes <br />and soils that are highly susceptible to erosion should be avoided when <br />other locations are available. Small drainage areas just large enough to <br />support a stock pond are the most desirable from the sedimentation stand- <br />point. <br /> <br />36 <br />