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<br />,!()r' " <br />'1':> J .J <br /> <br />. <br /> <br />. <br /> <br />41. . PLAN OF RESERVOIR REGUDATIO/lo- <br /> <br />a. General.- Thc authorizcd Pueblo Dam and Reservoir on the <br />Arkansas River would be operated to control floods to 5,000 c.f.s. down- <br />stream from Pueblo to John ~Iartin Dam wherever possible. This discharge <br />has been determined to be the safe channel capacity belOl< Pueblo F100d- <br />way to John t.lartin Dam. The design flood, the June 1921 flood as it <br />occarred, would be controlled with no rcleases. This would require <br />93,000 acre-feet of flood control storagc. Control of the design flood <br />without releases being made from the reservoir would generally be re- <br />quired because Fountain Creek would also be in flood stage when thcre <br />would be large inflows into the reservoir. Fountain Creek enters the <br />Arkansas River just below Pueblo. Uncontrolled flOl<s in the Arkansas <br />River below Pueblo Dam would generally approach the safe channel capacity <br />of 5,000 c.f.s. below Fountain Crcek. <br /> <br />b. OutZet caDaait)./ for flood control.- A gated river outlet <br />with a minimum capacity of 5,000 c.f.s. when the pool stage is at the <br />top of the conservation pool would be required to control dOl<nstrealn <br />flows to S,OOO c.f.s. With thcsc provisions, the flood control pool <br />could be evacuated through the outlet in about ten d~ys if dOlmstrecun <br />conditions permito <br /> <br />c. Joint use of flood control pool. - Part of tbe flood con- <br />trol pool would be used for conservation storage during the winter months <br />when upstream reservoirs in the Fryingpan-Arkansas Project would be <br />evacuated to provide storage for spring runoff. The joint use pool <br />would provide 66,000 acre-feet of joint use storage for the months of <br />November through ~larch. ' The remaining 27,000 acre-feet of flood con- <br />trol storage would be held inviolate for possible winter floods. The <br />conservation water in the flood control pool would be released by 15 <br />April each year. Studies of runoff and rainfall records for the sub- <br />~. . _ .: _ . bas in.above. l'ucbJo.DanL indica te_tha tmajor_f1o~od.p.r~oducing_ra ins_do_no~t. _ _ _ = _ _ <br />occur prior to 15 April, Rccords furthcr show that excessive runoff <br />does not occur prior to that date. <br /> <br />42, Preliminary operation studies by the Bureau of Reclamation <br />indicate that joint use of the flood control pool would he required for <br />threc seasons during the period of record 1928-1965. Plate 3 shows the <br />historic content of Pueblo Reservoir on 1 April for the period 1928 to <br />1965 "i th j oint use of flood control. <br /> <br />43. HYDROLOGIC FACILITIES.- Flood control regulations at Pueblo <br />Dam will require stream gaging stations both upstream and do"nstream <br />of the project. TIle existing stations on the Arkansas River at Portland <br />and Pueblo will meet these requirements. The recording reservoir gage <br />and tbe Class A weather station, I<hich will be provided by the Bureau <br />of Rcc1amation, "Iill be adequate for flood control regulation. Data for <br />forecasts for flood control purposes will be obtained from existing <br />facili ties and facil i ties insta lIed for other purposes of the project. <br /> <br />14 <br />