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<br />SALT YIELDS AT THREE SMALL BASINS; BADGER WASH, COLORADO <br /> <br />w <br />w <br />U1 <br />en <br /> <br />Background <br /> <br />Gaging stations were maintained by the U.S. Geological Survey on the Badger <br />Wash Experimental Area in western Colorado at Prairie Dog Reservoir, Middle <br />Basin, and West Twin Basin from 1977 to 1982. Continuous discharge and <br />electrical conductivity (ECl measurements were made and automatic samplers <br />were programmed to collect water quality samples periodically over the <br />duration of ephemeral discharge events. Water samples were analyzed for EC, <br />suspended sediments and TDS. Beginning in 1982, samples were analyzed for <br />suspended sediment concentration. Historic runoff from the 1966 to 1973 <br />period (Lusby, 1979) was then used to extend the average TDS data to estimate <br />a longer-term average annual salt yield from each basin (Table 4l. Because of <br />the infrequency of runoff-producing events and the short period of gaging <br />record, only rough estimates of TDS yield and TDS to TS ratios were devel- <br />oped. To further complicate the record, several events early in the gaging <br />period were only partly sampled due to plugging of the sampler intakes. <br /> <br />The Badger Wash experimental area is located approximately 25 km (15 mil west <br />of Grand Junction, Colorado. The area was set aside for scientific research <br />in rangeland erosion in 1952. The results of the erosion research are <br />reported by Lusby (1979). The climate at Badger Wash is primarily arid to <br />semiarid. Badger Wash Basin is underlain by the Mancos shale formation with <br />thin layers of sandstone outcropping at the higher elevations on the west and <br />north boundaries of the basin. Soils are poorly developed silty clay loams <br />and 10ams. They are shallow to moderately deep over Mancos shale bedrock. <br />Topography varies from steep. slopes at the headwaters to moderate and gentle <br />slopes at lower elevations. Channels are moderately incised on the steep <br />terrain and wider with rounded. banks on moderate and gentle terrain. Little <br />evidence of recent accelerated channel erosions exists. Vegetation is a <br />sparse to moderate cover of salt desert shrubs with perennial grasses <br />intermixed. In spring, annual grasses and forbs occupy normally vacant <br />openi ngs between perenni al p1 ants. <br /> <br />Badger Wash basin was heavily grazed by cattle beginning in the 1880's. <br />Beginning about 1915, many herds of sheep crossed the basin while trailing <br />from Utah winter ranges back and forth to Colorado mountain summer ranges. <br />The stock driveway was closed in 1957, but the basin continued to be grazed <br />during the winter and spring by resident herds of cattle and sheep until <br />1966. The basin has been grazed by sheep during the winter only since 1966. <br />A number of fenced watersheds have been ungrazed since 1953. <br /> <br />Resu1 ts <br /> <br />The overall average discharge of salts from the three basins for the 1966 to <br />1973 period was 0.11 t/ha/yr (0.05 tons/acre/yrl. This figure is roughly <br />comparable to the estimated annual discharge of salts on Wattis Branch (.08 <br />t/ha/yr) and Soldier Creek (.12 t/ha/yrl--two small drainages on Mancos shale <br />in the Price River Basin, Utah (USDI-BLM, 1982al. It is lower than the <br /> <br />9 <br /> <br />>.,< <br /> <br />