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I I I I I I I I I I I I I I I I I I I II-2 STUDY REACH 2 (TUCKER GULCH TO McINTYRE STREET) STATION 744+00 to STATION 885+00 Study Reach 2 encompasses most of the Adolph Coors Industries structures along Clear Creek and is the largest reach in the study area at 14,100 feet (2.7 miles). There are many crossings of the creek in this reach: Vasquez Street, Crawford Street, t\\Q pedestri an bri dges, the Co lorado and Southern Railroad, Coors Bridge No.3, and three aerial util ity pipel ines. There are several dams along this reach for agricultural and industrial water use, and numerous drop structures for control of the channel slope. Problem areas along Reach 2 include the inadequacy of the concrete walled channel to carry the 100-year flow, which is compounded by the backwater effects of the pedestrian bridges and the Crawford Street and Vasquez Street bridges. This results in overbank flooding which affects several industrial structures in the Coors Complex. Three aerial pipel ine crossings would likely be severed by high velocity lOO-year flows. There are t\\Q basic types of channel configurations in study Reach 2. Be- tween Ford Street and the Colorado and Southern Railroad bridge there is ap- proximately 2,600 feet of structural walled channel. This channel, with concrete walls and a natural cobble invert has a flow capacity of approxi- mately 6,000 to 10,000 cubic feet per second. Flow during the 100-year flood would be extremely unstable, however, because the steep slope of the channel creates very high velocities. Downstream of the C&S Railroad bridge the channel bank configuration changes from the vertical concrete walls to heavy rock riprap banks sloping between 1:1 and 3:1 (horizontal to verti- cal). The channel bank riprap was placed by Coors Industries as part of their relocation and stabil ization efforts along Clear Creek through their property. With few exceptions this channel has the capacity to carry the 100-year discharge of 13,470 cfs. STUDY REACH 3 (McINTYRE STREET TO YOUNGFIELD STREET) STATION 651+00 to STATION 744+00 This reach, 9,400 feet (1.8 miles) long, is the least developed floodplain segment of the study area. The only structures in this area are the Coors Industries Corrmodities Transload building, miscellaneous gravel operations and an asphalt paving pl ant. The creek is crossed by McIntyre Street, a railroad bridge serving the transload building, Interstate 70 and Youngfield Street. Two major water supply conduits cross Clear Creek near Eldridge Street and provide water from Ralston Reservoir to Denver's Moffat Treatment Plant. The channel between McIntyre Street and Eldridge Street is a continuation of the riprap channel section constructed by Coors Industries and described under Reach 2. Between Eldridge Street and 1-70 the channel maintains a re- latively straight alignment as it passes by the asphalt paving plant and the Jefferson County gravel operations. Just upstream of 1-70 the floodpl ain becomes relatively wide and flat and the channel is braided. The agricultural and industrial water diversions from Clear Creek along this reach are both numerous and complex. Downstream of Ford Street the Agri- cultural Ditch, the Farmers Highline Canal and Coors Industries maintain large diversion headgates. Further downstream are other diversion works; the Wannamaker Ditch; the Lee, Stewart and Eskins Ditch; the Croke Canal; the Rocky Mountain Ditch; and the Miles and Eskins Ditch. There are few problems in Study Reach 3, since the channel has the capacity to carry the 100-year discharge with the exception of the area upstream of the railroad bridge east of McIntyre Street. In this area the backwater from the railroad bridge can cause overflows to occur over the north bank and cause flooding at the Commodities Transload building.