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<br /> <br />In the above sedcad categories, "condition" was based upon the cover <br />values given in SCS Publication TR-55 for hydrologic condition for <br />pasture, grassland and range. Ground cover estimates were made in the <br />field by Division personnel. <br />Condition Vegetative Condition <br />Poor: < 50$ ground cover (or heavily grazed) <br />Fair: 50$ - 75$ ground cover (and not grazed) <br />Good: > 75$ ground cover (or occasionally grazed) <br />To arrive at the above curve numbers, the values for first and second <br />year growth were reduced by eight points to account for disking and <br />contour furrowing. These reductions seem to be consistent with <br />reductions made in sedcad curve number tables to account for disking <br />and contour furrowing (from fallow, with poor crop residue to row <br />crops, contoured, impervious soils). These reductions were made for <br />modeling 25 year events despite an opinion given in Peak Flow of <br />Colorado (SCS, 1984) on page 24, that adjustments for contoured or <br />terraced treatments should not be made for storm frequencies greater <br />than l0 years) <br />In selecting an appropriate curve number, the following Land Use <br />Descriptions that might reflect site conditions at Colowyo through the <br />second year of reclamation were taken into consideration: <br />Land Use Description Condition B Hvdro Group <br />Fallow, Bare Soil N.A. 86 <br />Fallow, Poor Crop Residue <br />Fallow, Good Crop Residue <br />Row Crops, Contoured, Impervious <br />Row Crops, Contoured, Pervious <br />Row Crops, Contoured, C. Residue <br />Small Grain, Contour, C. Residue <br />N.A. 85 <br />N.A. 83 <br />Vegetated 79 <br />Vegetated 75 <br />Good 74 <br />Poor Cover 73 <br />Small Grain, Contour, C. Residue Good Cover 72 <br />Herbaceous, 0~ Cover No Cover 85 <br />Herbaceous Fair Cover 71 <br />Herbaceous Good Cover 62 <br />