1986-06-13_GENERAL DOCUMENTS - C1981018

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I • -28- aspen, mountain brush and coniferous vegetation types. These drainages are either perennial or dependably contain flows sufficient to allow diversion during the irrigation season (Alvin Jones, personal communication) . The land use map and discussion with Mr. Jones, Range Conservationist with the Soil Conservation Service in Meeker, document that it is not the regional practice to irrigate alluvial deposits associated with ephemeral drainages contained within the 9 - 12 inch precipitation zone in Rio Blanco County. C. Salinity hazard of surface water based on data in the ERO study would be classified as "high" based on USGS criteria (USGS, 1970). D. Vegetation and soil pit information in the ERO Document indicate that Greasewood (Sarcobatus vermiculatus) , the most prominent vegetation species on the alluvial terraces adjacent to the Red Wash Channel is probably subirrigated. Greasewood is a salt tolerant phreatophyte and soil pits indicate an alluvial zone of saturation at depths of between 5 and 8 feet. Greasewood is not an agriculturally useful species and is, in fact, poisonous to sheep under certain conditions. Data collected by the permittee do not indicate the presence of agriculturally significant vegetation which might be expected to benefit from the high water table. This is supported by observations made on-site by Division staff in September, 1983. The potential agricultural importance of the high water table and • subirrigation is negated by the high electrical conductivity (EC) of the alluvial ground water. Analyses of ground water quality samples collected for Alluvial Well Qal - 2 located at the confluence of Red Wash and the White River indicate a range in EC levels from a low of 3,500 umhos/cm to a high of 12,000 umhos/cm between March, 1981 and August, 1982 (ERO, 1982). Based on a USGS irrigation water rating chart (USGS, 1970), the salinity hazard of such water could be rated "very high". References Cited ERO Resources Corporation, 1982. Red Wash Drainage Basin Alluvial Valley Floor study. 30 pp. Jones, Alvi-n,1983. SCS Range Conservationist. Personal Communication. United States Department of Agriculture, 1976. Land Use and Natural Plant Communities Map, Rio Blanco County, Colorado. 3 sheets. United State Geological Survey, 1970. Study and Interpretation of the Chemical Characteristics of Natural Water. United States Government Printing Office. 363 pp. Western Fuels-Utah, Inc. , 1980. Deserado Mine Mining Permit Application. 2. Scullion Gulch The AVF finding regarding Scullion Gulch has not changed from the original findings document. The Division and OSM concluded that Scullion Gulch is not an alluvial valley floor, on the following basis: