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I I I I I I I I I I I I I I I I I I II ~ ~ ~ ~ place. If sagebrush is sprayed or plowed, it should be done in strips perpendicular to any washes or existing flow paths. This will increase infiltration rates while decreasing overland flows. The success of vegetation treatment projects will be enhanced by using a diversity of plant species, insuring a lack of annual or noxious weeds, optimal orientation, and using a mix of treated and untreated acres. Limitations in this zone include soil depth, slope, native (or lack thereof) preferred plant species in the plant community, and precipitation. For example, a site may lend itself to one treatment over another because it has a good understory of native grasses and forbs. Such a site would be a good candidate for spraying to decrease the amount of sagebrush (in strips) and enhance infiltration rates over that site. The presence of good understory would decrease the need for reseeding. UNIT 2 - Mancos Terrace - The Mancos Terrace, covering 5,658 acres, is the other zone recommended for treatment as a result of this study. The elevation for the areas delineated on the map range from 4500 to 5200 feet. Precipitation on the Mancos Terrace ranges from about 7 to 10 inches yearly. This unit is within the Saltbush Zone as described in the resource area EIS (1983). The steep topography, thin soil and low precipitation over much of the terrace limit the potential for successful vegetation treatment. The ecological sites in the Mancos Terrace include the Desert Shallow clay and the Desert clay site. The Mancos Terrace Zone, as are the other geomorphic units within the Saltbush Zone (as discussed in the EIS), is utilized by domestic sheep in the winter and cattle in the spring. The predominant wildlife grazing in the watershed is by antelope and deer. The primary goal of a project in the Mancos Terrace would be to slow the flow of water and lengthen flow paths, as in the Pinion-Juniper-Sage Terrace. However, because of the limited precipitation, the potential for successfully reseeding on the Mancos Terrace is considerably less than in the P-J Terrace. Recommended treatment measures are harrowing and/or discing across the flow paths of the Terrace. A deep disc rangeland drill may make deep enough furrows. The recommended work pattern is to harrow around the tributary gullies and major concentrated flow paths. The harrowing should be two harrow widths per every 300 to 400 feet of slope and the harrowing should be located within 5 to 10 feet of the gullies or concentrated flow paths. Reseeding prescriptions would include vegetation adapatable to slightly saline to saline soils. Species that may grow include hycrest crested wheatgrass, streambank wheatgrass, and forage kochia. The maintenance or improvement of vegetation productivity would complete the success of the project. UNIT 3 - Upper Watershed - The Upper Watershed zone is 7