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Table TR 90-06-15 <br /> <br />~- " +F VALUES OF CROP~MANAGEMENT FACTOR C FOR PERMANENT PASTURE, GRAZEO <br />FOREST LAND, RANGE AND IDLE LAND (47) <br />Vegetative Canopy Cover That Contacts the Soil Surface <br />/ , <br />i~ <br />Type and Heights <br />Corer' Type' <br />0 <br />No appreciable <br />canoPY <br />Tall grass, weeds <br />ar short brush <br />with average <br />drop tall <br />of 20 in. or less <br />Appreciable brush <br />or bushes, with <br />average drop fall <br />height of 6.5 h <br />Trees, but no <br />appreciable low <br />brush. Average <br />G <br />W <br />25 G <br />W <br />$0 \ t~ <br />\_~ N. <br />75 G <br />W <br />25 G <br />W <br />0.45 <br />0.45 <br />0.76 <br />O.J6 <br />0.26 <br />0.26 <br />O.17 <br />O.17 <br />0.40 <br />0.40 <br />50 G 0.74 <br />W 0.34 <br />75 G 0.28 <br />W 0.28 <br />25 G 0.42 <br />W 0.42 <br /> Percent Ground Cover <br />20 40 60 <br />0.20 0.1o a.oaz <br />0.24 0.15 0.091 <br />0.17 0.09 0.038 <br />0.20 0.13 O.OBJ <br /> 0 J`b <br />0.13 0.07 0.035 <br />O.16 0.11 0.076 <br />O.IO 0.06 0.072 <br />0.12 0.09 0.068 <br />0.18 0.09 0.040 <br />0.22 O.14 0.087 <br />0.16 O.OB 0.078 <br />0.19 0.13 0.082 <br />0.14 0.08 O.OJ6 <br />0.17 0.12 0.078 <br />0.19 0.10 0.041 <br />0.23 0.14 0.089 <br />80 <br />o.m3 <br />0.043 <br />0.011 <br />0.041 <br />0.012 <br />0.039 <br />O.OII <br />0.038 <br />O.OIJ <br />0.042 <br />0.012 <br />0.041 <br />0.012 <br />0.040 <br />O.Ol3 <br />0.042 <br />100 <br />0.007 <br />O.OII <br />0.007 <br />0.011 <br />0.003 <br />0.011 <br />0.003 <br />0.011 <br />0.007 <br />0.011 <br />0.003 <br />0.011 <br />0.007 <br />0.011 <br />0.007 <br />0.011 <br />drop fall height SO G O.J9 O.18 0.09 0.040 0.013 0.003 <br />of 17 tt W 0.79 0.21 0.14 0.087 0.042 O.OII <br />75 G O.J6 0.17 0.09 0.079 0.012 0.003 <br />W 0.36 0.20 O.U 0.084 0.041 0.011 <br />'The listed C values require that the vegetation and mulch be randomly distributed over the entire area. For gr»e1 <br />forest land, multiply rhea values by 0.7. <br />'Canopy height is meuurcd u the average tall height of water drops falling from eaoopy to ground. Canopy eHcat e <br />inversely proportional to drop tall height and is negligible it tall height exceeds 33 k. <br />'Portion of total arcs suAarc that could be hidden (tom view by canopy in a vertical projection. <br />'G: rover at surfarc is grass, grasslike plaon, decaying compacted duH, or litter. W: mver at surface is mostly bmsE. <br />leaf herbaceous plants (weeds) or undecaytd midues or both. <br />~J <br />* From Engineering Hydrology Principles and Practice (Ponce, 1989) <br />from original in: <br />USDA Soil Conservation Service <br />National Engineering Handbook, Section 3, Sedimentation (1983) <br />TR 90-06 Exhibit 3 - 45 Revised 11/16/90 <br />