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<br />VIT. MAJOR REGULATION PROBLEMS. Regulation problems experienced during <br />the period of this report are discussed briefly in the following paragraphs. <br /> <br />a. Water Quality. Water qualjty problems including algal blooms and low dissolved <br />oxygen exist at certain tributary reseIVoirs. The principal water quality issues and problems <br />at each of the projects during 1992 are covered in a separate report prepared by the Water <br />Quality Unit. <br /> <br />b. Downstream Channel Capacity. Inadequate or reduced channel capacity is a <br />problem below many of the tributary reseIVoirs. Encroachment by natural plant growth due <br />to low flows, by flood deposits left in place, and by human construction and agriculture <br />practices are common. In some cases, downstream channel capacity is significantly less than <br />flood control releases. For example, the channel downstream of Cold Brook Dam is <br />undefmable due to residential construction. The channel capacity of the South Platte River <br />ow e Tn-Lakes projects hinders or prevents releases in accordance with the three- <br />reseIVoir (Chatfield, Bear Creek, and Cherry Creek) plan of regulation to evacuate flood <br />storage. Compounding this situation is the fact that the reservoir design routings for <br />Chatfield, Bear Creek and Cherry Creek Reservoirs were made independently of each other <br />and that the individual routings neglected 1) the effect of the releases from the other two <br />dams in the three-reseIVOir system, 2) the effect of the incremental runoff below the dams, <br />and 3 the actual channel ca aci below the three dams. <br /> <br />This year's experience with releasing water at the USBR projects has provided <br />valuable information on the downstream channel capacities at these projects. At Boysen <br />ReseIVoir, the capacity of the downstream channel is limited to around 11,000 cfs by a <br />bridge crossing at Thennopolis. The design discharge is 15,000 cfs. At Yellowtail, the <br />maximum nondamaging release appears to be around 12,000 cfs. The design discharge is <br />20,ooocfs. A release of 15,ooocfs at Canyon Ferry was made without causing damage. The <br />design discharge is 15,000 cfs. <br /> <br />c. Releases for Purposes other than Authorized Project Functions. No releases <br />were made for purposes other than authorized project functions. <br /> <br />d. Potential Hazardous Conditions. A potential problem exists if water is released <br />over the project spillways where the land downstream of the project has been developed into <br />urban areas. A hazard-ta-life condition exists if a significant flow of water is discharged over <br />the spillways at, the_se projects. <br /> <br />VITI. WATER CONTROL MANUALS. Attempts to obtain funding for revision <br />and/or preparation of Water Control Manuals through the O&M budgeting process have, <br />continued to be unsuccessful. The District is allocating limited funds from other functions <br />to work on high priority manuals. Final approval on the completed Papillion Creek Water <br />Control Manual is still forthcoming from the Missouri River Division. The Lake Audubon <br />and Westerly Creek Manuals are expected to be completed in Fiscal Year 1993. <br /> <br />18 <br /> <br /> <br />'. <br />{' <br /> <br />\ <br />I <br />! <br />I <br />, <br />I <br />I <br />I <br />.1 <br />I <br />i <br />