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Novemlxr 1993 Raton Creek "Small Ama Ezemptian ~ 3 <br />• The required length of fences should be calcula[ed assuming a flow depth of 1 foot. Actual <br />fence installation should be a minimum of 1.5 fee[ to allow free board and a fattor of safety on <br />the permissivi[y. <br />The sil[ fence should be ins[alled in accordance with the manufattures recommends[ions. <br />Designs assume regular inspections and maintenance. <br />1.6 SAE Request <br />Given the limited size of both disturbed areas, the previously discussed drainage and sediment <br />control measures (designed [o effettively prevent significant adverse downstream water quali[y <br />impatts), and [he lack of any underground mine water discharge sources, EFMC requests DMG <br />approval of small area exemp[ions for bo[h sites. <br />2.0 BURLINGTON LOADOUT <br />The Burlington loadou[ has recen[ly been reclaimed and the area, a[ the direction of the <br />landowner (Ci[y of Trinidad), is temporarily being used and main[ained as cropland. The Ci[y <br />of Trinidad, has indicated that it plans to develop the site for disposal of [reared municipal <br />sewage sludge and has initiated contatts with the Colorado Department of Health [o coordinate <br />required permits. Given the present site configuration, EFMC has competed hydrologic designs <br />to control runoff from the newly regraded and plowed area. <br />• The loadout area includes approximately 3 acres of developed cropland. Runoff from the site <br />will be controlled by collection berms which will divert al] run-off to a sediment fence located <br />at [he northeast corner of the si[e as shown on [he Burlington No. 1 Loadout Map, (Exhibit L). <br />Run-on to the site is effectively controlled by the farm-light use road located along [he <br />northwest edge of the loadout. All drainage s[ruttures will be constructed [o safely pass the <br />peak discharge from a 10-year, 24-hour event. <br />2.1 Hydrology Designs <br />Runoff peak discharge calculations were performed utilizing the SEDCAD+ computer model <br />consistent with the me[hodology previously discussed in this Exhibit. The sediment fence and <br />diversion berms were designed to handle the peak discharge from a 10-year, 24hour storm event. <br />2.2 Hydrology Inputs <br />All hydrology inpu[s are shown on the SEDCAD+ computer prin[outs (see a[tached). <br />The CN numbers used for bo[h areas were ob[ained from Procedures for Determining <br />Peak Flows in Colorado and Technical Release No. 55 (USDA-SCS, 1980). Based on soil <br />type and vegetation cover, curve numbers were determined using Table 2-2a and 2-2d, <br />USDA-SCS TR-55, for the following Conditions: <br />lJ <br />A~~956BTR0].PGS <br />t vzvss to,,,, TerraAfatrix/ACZ lnc. " P.O. Boz 7740/8 'Steamboat Springs, Colorado 80477 " (303f 8796260 <br />