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TABLE 2. Channel Sizes <br />Waldo Canyon <br />(above US 24) <br />Bottom width (feet) <br />Side slope (horiz.,H to 1 vert.) <br />Design depth, D (feet) <br />~. Y X., (..~ .~ <br />Sediment & Sediment Control <br />12.0 <br />2.0 <br />3.3 <br />East tributary <br />8.0 <br />2.0 <br />1.4 <br />No information is presently available regarding the sediment <br />transport regime of Waldo Canyon and only a limited amount of <br />data is available on Fountain Creek. The US Geological Survey <br />collected periodic suspended sediment data from December, 1984 <br />through September, 1985 and again from December, 1985 through <br />Septmeber, 1986 at the Fountain Creek gaging station just west of <br />Colorado Springs (M07103700). This limited sampling gives some <br />information to the sediment transport characteristics of the <br />area. The Fountain Creek produces generally low concentrations <br />of suspended sediment, from 10 to 200 mg/1, during the low and <br />near average flows of 15 cfs (29 year average). However, during <br />the spring snowmelt season when the ground thaws and rapid melt <br />commences, the stream averages several hundred mg/1 of suspended <br />sediment with the recorded maximum concentration at the station <br />being 5,120 mg/1 in 116 cfs of flow on April 30, 1985 which also <br />corresponded to the day of peak runoff for that year. Some <br />particle size analyses by the USGS indicate that during low and <br />normal flows, the transported sediment is distributed about 25B <br />sand size and 758 silt size particles. As expected, during the <br />higher runoff, this distribution is approximately reversed. <br />Thus, during higher runoff, onsite sediment control measures will <br />be most effective because the larger particles are more easily <br />controlled by filtering and sedimentation. <br />-SEQm(gT!£-Wfii- IT~d'S'd1T"C[~7t~evrstroi pEagram to <br />neiniwise ti~et aatary'~~ tk~at ie do1lres~e8 to <br />the ataeems. This sediment control plan will include the <br />following elements: 1) nv.dsai+~ge oi~anne2 evnstrnetion µ11l <br />occur It season of March through June; <br />,7 -2) cu be installed wherever it is necessary <br />for Waldo Canyon or the East tributary; <br />3) hay--i9a ed between the drainage cteamtels and any <br />areas that hav4 been di.at+rrbed and not reclaimed, either <br />temporarily or permanently (as shown in figure Exhibit G-3); and <br />4) a sediment pond will be. maintained below the confluence of the <br />two streams and above trighway US 24. This pond will be utilized <br />to provide sedimentation of particles transported in the runoff <br />which results from.land.dieturbance ceased by the pot eparation. <br />+p-.J <br />~. ~ <br />f <br />Surface Water Responses: Summit Pit Jlpplicatioel page B <br />