OCR Text |
Show Livestock water developments-- Spring developments, catchments, and reservoirs are frequently used on public ranges to increase production, redistribute stock, or change forage utilization patterns by adjusting the water supply for livestock. Common practices are the creation of catchment basins through excavation or blockage of a small drainage, diversion of flow to a trough, storage in tanks, and flow enhancement ( often using a pipe driven into the source of a slow seep). Twenty- three developments of springs and reservoirs were proposed in the NRA during 1980- 1985, of which 15 were constructed. Most water developments for range cattle proposed in the recreation area use either springs or seeps with low flow, or catchments. Catchments trap and store water that otherwise would run off downstream, so that one effect is a minor lessening of recharge to the affected drainage. Also, improper location and maintenance of the water- holding structures can cause alteration of natural stream channels. If a low- flow water source is used, water diverted from such a source to a tank or trough may cause a break in flow over part of the streambed, drying up a portion of the stream channel. Similarly, flow enhancement can deplete seasonal recharge more quickly and lengthen the dry period. Such changes can be critical to wildlife or local areas of riparian habitat. Improvements for grazing operations-- Roads, trails, and fences may be constructed in new areas ( or closed and removed) to assist in a change of grazing operations. The effects on water resources are usually indirect, except that fencing is sometimes used to exclude cattle from watered areas. Grazing systems-- These are implemented through schedule of placing stock on the range, division of ranges into pastures, and determination of optimum stocking rates. Any change in grazing system is likely to generate ecosystem changes, which in turn can influence the hydrologic balance of the allotment and thus the water resources of the NRA. Of all range management practices, those involving water use by cattle probably have the most far- reaching effects on water quality. Where cattle have direct access to a natural source, it will be fouled by feces. Several bacterial, protozoan, and viral diseases can be transmitted from cattle to humans via this route ( Buckhouse and Gifford 1976; Charles Gerba, University of Arizona, personal communication, 1986), in addition to the adverse aesthetic effects. ( According to Gerba, the protozoan Cryptosporidia has been implicated in human disease, with cattle as a vector.) These effects set up potential competition for the water resource between range cattle and backcountry recreationists. Studies by Kunkle ( 1970) and Buckhouse and Gifford ( 1976) indicate that bacterial contaminants from cattle feces may not be transported very far from the source; thus, water quality effects easily could be mitigated by 51 |