Laserfiche WebLink
Memorandum to Henry Bazbe, MCC <br />July 28, 2000 <br />Page 4 <br />' multiple-regression analysis was used to develop two equations; one based on mean annual <br />streamflow and mean basin elevation, and the other on drainage area. The two equations for the <br />' Central Region of Colorado are: <br />LSS = 23.1 Qaes Eh -3.4 (3) <br />' where: Lys =mean annual suspended-sediment load, tons <br />Qa =mean annual streamflow, acre-feet <br />' Eb =mean basin elevation divided by 5000, feet <br />Lss = 109 Ad.so (4) <br />where: Lss =mean annual suspended-sediment load, tons <br />Ad =drainage-basin area, squaze miles. <br />Based on a mean annual runoff of 1900 acre-feet (2.62 cfs), a mean basin elevation of 8460 feet, <br />and a drainage basin of 4.0 squaze miles the following sediment loads were obtained: <br />t Equation (3) = 660 Tons /year <br />' Equation (4) = 330 Tons /year <br />A recommend method is to average the two values, which results in 495 tons/yr. This is <br />' equivalent to a sediment load of 0.32 AF/year or 0.08 AF/min/yr at a unit weight for sediment 70 <br />Ibs/cubic foot. <br />' A check on the sediment yield in terms of suspended sediment concentration shows an average <br />concentration of about 190 mg/L. Estimates during the field observation on June 19, 2000 <br />support this average concentration. <br />' CONCLUSION <br />' Deep Creek between the Upper and Lower gaging stations is characterized by a we]]-incised <br />channel with cobble- to boulder-size rock common along the streambed. The stream transports <br />significant volumes of sandy sediments, especially during peak flows, as evidenced by the large <br />buildup behind the beaver dam. The armoring of the channel bottom limits the amount of <br />vertical degradation. <br />1 <br />C \831-032\530ard\finalmemo doc <br />1 <br />' Wright Water Engineers, Inc., 2490 W. 26P1 Avenue, Ste. 100A, Denver, CO 80211 <br />Tel. 303/480-1700; Fax. 303/480-1020, e-mail:krwright@wrightwaler.wm <br />1 <br />