REV91705 - Laserfiche WebLink

Home Browse Search

1.3 Project Description The project consists of three parts (SAE facilities): a Fan Bench, a Staging Area, and a Topsoil Storage Pile. 1.3.1 Location Locations are shown on Drawing LPG-103F, 7/29/94, Lone Pine Gulch Fan/Portal Bench Design. 1.3.2 Configuration Enclosure 1 is a map (1' = 200') which portrays the three SAE elements. Enclosure 2 is a map (1" = 2,000', an extract of the Somerset, CO, 1:24,000 USGS Topographic Map Quadrangle) that indicates the general outlines of four watersheds that extended beyond the limits of the larger scale map. The drainage system is described by a number of watersheds, ditches, culverts, and vegetative debris filters. Characteristics of the features are presented in Enclosure 3. The Topsoil Storage Pile analysis considers six Watersheds (1 through 6). Watershed 1 is the natural slope above the Topsoil Storage Pile. Waterbars transfer flows across the road above the intersection with the watershed and prevent runoff from Watershed 1 from combining with Watershed 7 flows to Culvert C-1. Runoff from Watershed 1 is intercepted and diverted towards the west a sufficient distance to avoid the Topsoil Storage Pile, and is released back to sheet flow by a gradual reduction in the depth (tapering) of the ditch. This Ditch, D-1, is designed to capture the runoff from a 10-year, 24-hour storm event, and is located a minimum of ten feet from circumvential ditches (Ditches D-2 and D-3) located above and at the toe-of-slopes of the Topsoil Storage Pile. Ditch D-1 is seeded, but is considered as an erodible channel in this review. Runoff from the area between the interceptor ditch D-1 and the circumvential ditch D-2 (west side of the Topsoil Storage Pile, Watershed 2), and runoff from the southwest quadrant (western up-hill portion of the storage pile, Watershed 3) drains to circumvential ditch D-2. The runoff is diverted around, and is distributed (by energy dissipator filter fencing and tapering of the ditch) before the silt fence below, the Topsoil Storage Pile. Similarly, runoff from the area towards the east between the interceptor ditch D-1 and circumventia] ditch D-3 (Watershed 4), and the southeast quadrant of the Topsoil Storage Pile (Watershed 5) drains to circumvential ditch D-3. The runoff is diverted around, and is distributed (by energy dissipator fencing and tapering of the ditch) before the silt fence below, the Topsoil Storage Pile. Circumvential ditches D-2 and D-3 are designed to pass the runoff from a 10-year, 24-hour storm event. Runoff from the down-hill side of the Topsoil Storage Pile (Watershed 6) is released, through a filter fence, directly into vegetative debris (filter). (Lone Pine Gulch SAES As-build Review, 24 May 95, Page 2 0[ 13) ~~~wa~ ~v-~+o`y qs-