Laserfiche WebLink
<br />About 86 percent of the average annual salt load contributed by <br />Virgin Valley is due to inflow at the Littlefield, Arizona gage and to <br />natural causes, and the remaining 14 percent is man-induced, primarily <br />due to irrigation. Irrigation is the most significant man related <br />activity in the Virgin Valley area. Factors which increase salt concen- <br />tration are evaporation from stream surfaces, erosion, consumptive use <br />by vegetation, and movement of water through strata containing soluble <br />salts. Saline soils (Figures 12, l3-l3C) and underlying geologic for- <br />mations (Figure 4) with high salt content are the major salt source <br />areas. Salts are added to the river system by irrigation drainage waters <br />when more saline waters or readily soluble salts are present in the flow <br />path. <br /> <br />Scale <br /> <br /> <br />f <br /> <br />L'- <br />m S.11", {1n<lUdn c..Co]l <br />0,....5111,. <br />.-. Mydro'09tc Iot.MdII'7 <br /> <br />ltat,: Soul"Cn IlIClude c_1nU10ll <br />ot 9_1091. 10111 IlIlt..cer <br /> <br />~/ <br />, <br />I <br />" <br />i <br /> <br />o 5 10 miles <br />. <br /> <br />I <br />\ <br />I <br />l <br />\ <br />I <br />I <br />I <br />I <br />I <br />1---. <br /> <br />1~. <br /> <br />~: <br /> <br />-.- <br />.._.~-.. <br /> <br />Figure 12 <br />SALT SOURCE <br /> <br />0'.1(. Z8G <br /> <br />USDA-SCS <br /> <br />Virgin Valley Subeyaluation Unit <br />Arizona. Neyada. Utah <br /> <br />of the Virgin Riyer Unit <br /> <br />Colorado Riyer Basin Salinity Control Program <br /> <br />28 <br />