FLOOD10207 - Laserfiche WebLink

Home Browse Search

SECTION m STUDY AREA DESCRIPTION Section III gives an ovelView of the "Rocky Flats Plant Drainage and Flood Control Master Plan" study area. Figures, tables and text are provided to describe the drainage basins and their characteristics, including topography, soils, geology, and groundwater. The Rocky Flats drainage area lies mostly in the Big Dry Creek basin. Big Dry Creek is an 86 square-mile tributary of the South Platte River. Its confluence is 42 miles downstream of Rocky Flats near Brighton, Colorado. The limits of the "Rocky Flats Plant Drainage and Flood Control Master Plan" (Master Plan) study area are Indiana Street on the east; the northern edge of the Walnut Creek Basin and State Highway 128 on the north; the upstream limits of the Rock Creek, Walnut Creek, Woman Creek, and Upper Big Dry Creek basins on the west; and the southern boundary of the Upper Big Dry Creek drainage basin on the south. There is a study area extension east of Indiana Street that was used to provide verification with existing master drainage planning done by the Urban Drainage and Flood Control District (UDFCD). This extension includes the Walnut Creek basin from Indiana Street to the spillway of Great Western Reservoir and the Woman Creek and Upper Big Dry Creek basins from Indiana Street to the spillway of Standley Lake Reservoir. A location map is given on Figure III-I. The basins studied are shown on Figure III-2, sheets 1 and 2. Sheet 1 provides overall drainage basin delineation, while sheet 2 shows more detailed sub-basin delineation within the plant boundaries. Five streams, all ephemeral, affect the study area. These streams are Walnut Creek, Woman Creek, Upper Big Dry Creek, Coal Creek, and Rock Creek. Of these, Walnut Creek and Woman Creek are the most important to this study because they drain the majority of the Rocky Flats Plant site. Walnut Creek and its tributaries head in the study