Laserfiche WebLink
Predicted Peak Flows. The annual mean and select peak discharges have been predicted for • <br />the following drainages in and proximate to the Seneca II-W Mine: 1) 005 Culch; 2) 006 <br />Culch; 3) Hubberson Gulch; 4) Watering Trough Culch; 5) Dry Creek; and 6) Sage Creek. <br />Discharges were predicted using techniques outlined in the USGS Water Resources <br />Investigations Report 85-4086, titled Estimation of Natural Stream Flow Characteristics in <br />Western Colorado (Kircher et al., 1985). The techniques used to predict discharge <br />characteristics for the si x drainages incorporated the use of regres sion relationships <br />determined from historical streamflow records in western Colorado. Basin parameters and <br />precipitation records were used to correlate discharge characteristics of four different <br />regions of western Colorado: 1) 1•fountain; 2) Rio Crande; 3) Southwest; and 4) Northwest. <br />A71 six drainages lie within the northwestern region as outlined by Kircher et. al., <br />(1985). The regression model developed for this region is as follows: <br />(b <br />) E <br />(6 <br />) <br />A(b1) <br />(64) <br />Z <br />3 <br />P <br />B <br />0 = a <br />SB <br />where, <br />0 =discharge (cfs) <br />A =drainage area (min) • <br />P =mean annual precipitation minus 10 (i n) <br />E <br />= mean basin elevation minus 5,000 per 1,000 feet (ft) <br />B <br />' S <br />= mean basin slope (ft/f t) <br />B <br />i <br />and, <br />a, 61, bZ, 63, and b4 are regression coefficients. <br />Using this regression model, the mean annual discharge and peak discharges for the 2-, 5-, <br />10-, 25-, 50-, and 100-year recurrence intervals were predicted for each drainage at the <br />following locations: 1) 005 Culch at confluence with Dry Creek; 2) 006 Gulch at <br />i confluence rvith Hubberson Gulch; 3) Hubberson Culch at confluence with Watering Trough <br />Culch; 4) Watering Trough Gulch at confluence with Hubberson Gulch; 5) Dry Creek at Site <br />SW-52W-SCS (SB0068); and 6) Sage Creek approximately one mile below the Sage Creek <br />Reservoir (see Exhibit 7-1 ). T.a ble 7-30 presents the regression equations and <br />coefficients applied for each discharge characteristic based on the northwestern region <br />' regression model (Kircher et. al, 1985). Table 7-31 presents the results of the <br />calculations for each drainage. <br /> • <br />From Table 7-31, it is evident that the regression models generally predict higher peak <br />discharges for basins with larger wa[ershed areas. However, the regression model for the <br />91 <br />