WSP04845 - Laserfiche WebLink

Home Browse Search

6 Badger Wash. Their conclusions included: 1) a runoff:rainfall ratio .... W greater than 0.50 probably is not unusual in the areal 2) much of c.n ....:i the loose material on the hillslopes was removed; and 3) aspect played an important role in erosion in that the north facing slopes were steeper and had a greater depth of loose material due to frost heave than that of the south facing slopes, thus providing more material for erosion. According to their measurements that storm, which pro- duced 30 minutes of runoff, resulted in the computed soil loss of 34.5 tonnes per hectare (15.4 tons per acre). The effects of land use on the area have been studied, also. Schumm (1964) noted that in the spring following the last severe frost, the surfaces of slopes are unstable and that tracking by animals at that time of year could cause important downslope movement of soil. The Bureau of Land Management (1978) investigated the influence that gra~ing has on vegetative cover, infiltration and compaction of soils, runoff, and sedimentation. Their findings included the following: 1) range deterioration was halted and increase in ground cover of desirable grasses resulted when yearlong gra~ing was changed to a summer grazing system; 2) with more grazing, there was less infiltra- tion due to loss of plant cover and increased compaction of soil; 3) grazing increased the compaction and the bulk density of the soil which, in turn, increased runoff and sediment yield; and 4) heavily grazed watersheds produced 30% more runoff and 45% more sediment than ungrazed watersheds. Their conclusions generally verify those reached by Lusby, et al. (1971) who, furthermore, observed that early in the year, grazed watersheds produced much more runoff than