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<br />Arona Pond Modifications <br /> <br /> Existing Stage/Storage Proposed Stage/Storage Increase <br />Elevation Area Storage Area Storage area volume <br />(ft. ) (ac.) (ac.ft.) (ac.) (ac.ft.) (%) (%) <br />888* 2.00 0.00 3.84 0 92 -- <br />890 2.73 3.53 4.35 8.29 59 135 <br />892 3.45 9.70 4.66 17.30 35 78 <br />894 3.90 17.04 4.97 26.93 27 58 <br />896 4.34 25.28 5.3 37.20 22 47 <br />898 5.12 34.73 5.63 48.13 10 39 <br /> <br />Table 1. Existing and Proposed Stage/Storage <br /> <br />* Existing area at 888 estimated <br /> <br />Table 2. Model High Water levels* <br /> <br />Design Event Existing Drainage Areas Arona Site Developed <br /> Pond Bounce Pond Bounce <br />(SCS Type II) HWL (ft. ) HWL (ft. ) <br />2 -year/24-hou r /2. 8-i nches 891.3 3.3 891.5 3.5 <br />5-year/24-hou r /3. 6-i nches 892.8 4.8 893.0 5 <br />10-year/24-hour/4.2-inches 894.1 6.1 894.3 6.3 <br />100-year/24-hour/6.0-inches 897.8 9.8 898.0 10 <br /> <br />* Model simulations assume: 1.Weir is removed, <br />2.Pipe invert of 897.23 controls pond outflow <br />3. Lift station draw down to NWL of 888 <br />4. Pond volume increased as proposed in Table 1. <br /> <br />Note: Simulated HWL for 1 OO-year event under existing conditions is 901.9 <br />Note: Low structure elevation is 898.48 (corner of apartment garage) <br /> <br />Table 3. Lift Station Draw Down Time <br /> <br />Design Event Approximate Drawdown Time (days) <br />(SCS Type II) 1 cfs Lift 2 cfs Lift 3 cfs Lift <br /> Station Station Station <br />2-year/24-hour/2.8-inches 7.6 3.8 2.5 <br />5-year/24-h ou r /3.6- inches 11.2 5.6 3.7 <br />10-year/24-hour/4.2-inches 14.4 7.2 4.8 <br />100-year/24-hour/6.0-inches 22.1 11 .1 7.4 <br />