Laserfiche WebLink
<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />CENTRAL CITY MASTER DRAINAGE STUDY <br /> <br />4 <br /> <br />The Nevada Gulch tributary of Gregory Gulch is comprised of <br />Nevada and Spring Creeks. Nevada Gulch drains 704 acres to the <br />confluence with Eureka Gulch. Elevations range from 9974 feet to <br />8380 feet. Both drainages have experienced extensive mining <br />operations. These operations have left tailings piles that are <br />unstable and at the angle of repose throughout the basins. In <br />several locations on Spring Creeks, tailings pilings extend into <br />the creek itself. <br /> <br />1.3 <br /> <br />Previous Studies and Information Used in Report <br /> <br />CWCB (1987) is a flood hazard identification report by the <br />Colorado Water Conservation Board. This study and its technical <br />addendum were the basis which provided much of the field <br />information used in the conceptual design. The HEC-2 Hydraulic <br />Program was used to model water surface profiles through Central <br />City. HEC-2 data used by CWCB in their 1987 study was obtained <br />to assess the impact of drainage modifications on the 10 and 100- <br />year profiles. <br /> <br />Two-foot contour mapping provided by Central City by Ray & <br />Associates, Inc. (scale 1 inch equals 100 feet) completed in <br />July, 1975, was used in this study. The reduced version of this <br />mapping from CWCB (1987) is used herein to locate improvements <br />and aemonstrate their effect. <br /> <br />Additional information includes utility mapping <br />Central City, also that used the Ray & Associates, <br />as a base and aerial photograph, date unknown, <br />Central, City. <br /> <br />provided by <br />Inc. mapping <br />provided by <br /> <br />.' <br /> <br />HydroDynamics Incorporated <br />