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material may have 100 percent passing the 3/R-inch sieve, 70 percent passing <br />the MB sieve, 30 percent passing the N40 sieve, and less than 30 percent . <br />passing the N200 sieve for a permeability of 2 ft/day. <br />The toe drain should be placed as shown on Exhibit 13-5. The underdraln <br />system should consist of a series of six-inch diameter Schedule 3034 <br />perforated pipes surrounded by a minimum of six inches of free draining <br />granular material. The granular material should extend up to the bottom of <br />the next bench and should contain less than 3 percent passing the M200 sieve <br />and more than 50 percent retained on the N4 sieve. The granular drainage <br />materials will be wrapped •.rlth Mlr aft 140N filter cloth. An adequate layer <br />of fill material should cover the drainage blanket in order to maintain its <br />I <br />integrity. <br />3. The embankment section be overconstructed with approximately one foot of <br />additional material [n the central portion of the dam to account for overall <br />settlement of [he natural subgrade soils and compacted embankment materials. <br />The entire embankment, including adjacent dlstu[bance areas, disturbed by <br />construction will be stabilized with respect to erosion by seeding the area . <br />irunediately after construction is complete in accordance with the Reclamation <br />Plan. Areas in which the vegetation is not successful or where rills and <br />gullies develop, shall be repaired and reveq etated in accordance with the rill <br />and gully plan. <br />Selected References <br />Barfield, B.J., Warner, R.C., and Haan, C.T. i9R 3. Applietl Hydrology and <br />Sedimente logy Eor Disturbed Areas. Oklahoma Technical Press, Stillwater, Oklahoma. <br />Dodson d Associates, Inc., Houston, Texas. 1986. "Pipe Culver[ and Trapezoidal <br />Ctia nnel Analysis". User's Manual and Program Reference. <br />McKool, D.K., Brown, L. C., Foster, G.R., Mutchler, C.K., and L.D. Meyer. 1987. <br />"Revised Slope Steepness Factor for [he Universal Soil Loss Equation". ASAE - Soil <br />and Watec Division (approved for pubLicat ion - June, 1987. <br /> <br />NOAH Precipitation Frequency Atlas of the Western States. Volume II. Colorado, <br />1973. <br />Renard, K.G. i9R 7. Principles of Soil Erosion Control: Rangelands. USDA-ARS, <br />Tucson, Arizona. <br />Simonton, J.R. 1987. Soil Loss Equation Using the Universal Soil Los s Equation, <br />Revised USLE for Ranyeland, Ve[sion R.17. USDA-ARS, Tucson, Arizona. • <br />13-4-12 Revised 07/15/97 <br />