Agenda - 11-19-1985 - Laserfiche WebLink

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.-.- . Mr. Ken R. Thompson Page -6- May 15, 1985 : . . ANNEX A MODEL ASSESSMENT of Modified Pro•osed O•eration of the I./seer Eno . . $ ( River Water Resources S stem in Oran•e Count Table 1 gives the volume corresponding to various levels of drawdown for the existing spillway elevation (614 ft MSL) and the proposed elevation (616 ft MSL) . Drawdowns are noted as both feet below the - -- - spillway crest and as percent of storage, to aid in interpretation of values given in the water shortage ordinance. k . TABLE 1 • . , iPercent Existing Conditions Proposed Conditions Storage spillway 614 ft MSL Spillway 616 ft MSL . V Volume Drawdown Volume Drawdown (Ac-ft) (ft) Ac-ft) (ft) k . 100 1307 0 1626 ' 0 ' ,..;.. 60 784 4.2 976 4.4 .i. 50 653 5 .6 813 5.9 40 523 7.2 650 7. 6 %., „ . . r?-t ( 30 ' 392 9.0 488 9.6 , le, .20 261 11. 0 325 . 12.0 J.'..' . Several computer models were developed to analyze the yield from the .R, . reservoir and river basin system supplying the study area. The models differed in the operating conditions assumed. The models attempted to reproduce actual operating conditions. ..,-., . e- Under proposed operating conditions, the -water withdrawal restrictions given in the ordinance and with instream flow releases noted in the ii table on page 3 above, we estimate that the total yield from the system is 2. 6 MGD. F. t. This yield is based on the occurrence, once in 40 years, of a condition at Lake Orange where the usable storage is zero. The model, however, shows that there would be 19 periods in which Lake Orange would be below 20 percent, or about 5 percent of the time. .,. F' . - .;g7t . ( . 0 . , 4 f 4,7 i., . i .