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~ . . .' IlOl01n 4 " . CllAPl'ER 5 _ FLOOD CONTROL OPERATION 17. FLOOD CONTROL OPERATIOO REQUIREMENTS ( a. Paonia ram and Reservoir v111 be operated for nood control in accordance v1th nood control regulations prescribed by the Secretary of the Army. A draft of the regulations, including the flood control oper- ating plan is contained in Appendix A. The regulations, together with the flood control operating plan, define the schedule for flood control operation of Paonia Reservoir. The regulations provide that when \later is stored in the flood control space (above elevation 6.373.0 ft.) in the res- ervoir during the snawmel t season and snawmel t forecasts indicate that snowmelt runoff of damaging proportions is anticipated, the vater should be released as rapidly as possible at rates not to exceed 3,500 c. f. s. in Horth Fork Gunnison River at Somerset, 1nso1'ar as possible. Under normal operating conditions during the snawmelt season (reservoir storage belov normal full pool elevation), reservoir release rates at no time will cause flovs at North Fork Gunnison River near Saaerset gage to exceed 3,500 c.t.s. because of the design limitations of outlet facilities as shawn on chart 9. b. Because Paonia Dam and Reservoir have been designed and built pri- marily as a conservation project with tlood control as a secondary goal, the flood control regulations gi 'Yen in Appendix A, are designed for objec- tive nood control operation of Paonia Reservoir to the extent that it d()@s not in any way interfere with the pr:lmary purpose ot filling the reservoir by the end of the snowmelt season (30 June). lB. LIMITATIONS ON STORAGE a. Operational limitations on storage in Paonia Reservoir are specified by the nood control operating plan which accaupanies the nood control regu- lations given in Appendix A to this report. ( b. Although all of the j oint use storage of Paonia Re servoir (17,000 acre-feet) is available for flood control purposes, it is too small in rela- tion to the magnitude of the reservoir inflovs, and, therefore, only partially effective in controlling nood novs in North Fork Gunnison River, as illus- trated on charts 15 and 16. Available surcharge above normal full pool (be- tveen elevation 6447.5 ft. and 6454.1 ft.) is only about 2,300 acre-feet, and 18 not very effective for flood control purposes because of the small reser_ voir area and the proportionally large uncontrolled spillway structure. 19 . LIMITATIONS ON REIEASES ^, a. Releases from Paonia Reservoir shall be restricted, insofar as possible, to limit novs at North Fork Gunnison River near Somerset so as not to exceed 3,500 c.f.s., and shall not be changed more than 200 c.f.s. per hour. 15