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Dams: <br />Certain Facts Related to the September 2013 Flooding <br />Little Thompson River Watershed, Colorado <br />O�'pD pPn SRF�iy BRA <br />�Rr�kG snarti Si�+CE ineq <br />Dam Name <br />Reservoir <br />Normal Storage <br />(acre-feet) <br />Reservoir <br />Flood Storage <br />(acre-feet) <br />Reservoir <br />Area <br />(acres) <br />Jurisdictional <br />Height (ft) <br />Sunset Lake <br />8.6 <br />19.26 <br />2.5 <br />6 <br />Willow Lake <br />26.67 <br />59.5 <br />5.5 <br />10 <br />Rainbow Lake <br />37.3 <br />48.9 <br />6.5 <br />10 <br />Meadow Lake <br />32.3 <br />90.38 <br />7 <br />10.1 <br />Mirror Lake <br />18.16 <br />29.91 <br />4 <br />10 <br />Totals <br />123 <br />248 <br />26 <br />Meadow Lake classified as a "minor size, low hazard" dam in accordance with dam safety Rules. All <br />other dams were considered "non -jurisdictional" (10 feet or less in height) according to Rules. (see <br />references). All dams were reportedly built in the late 1950's. <br />Meadow Lake dam is inspected every 6 years. Last regular inspection — 11/7/2008 recommended <br />outlet works rehab; Outlet works rehab project final construction inspection 11/16/2012, project <br />accepted for full use April 3, 2013. Dam considered in satisfactory condition prior to September. <br />All other dams within Big Elk Meadows HOA are 10 feet or less in height and considered "Non - <br />jurisdictional" per Rules, no formal inspections required. <br />Flooding: Preliminary Results of Analysis <br />Rainfall -Induced: The total volume of rain that fell on the subbasins and the percentage of the total <br />is as follows: <br />Subbasin <br />Rainfall <br />(Ac -ft) <br />Runoff <br />(Ac -ft) <br />% of total <br />Runoff <br />Peak Discharge % of Peak <br />(cfs) Discharge (cfs) <br />Meadow <br />14,110 <br />10,850 <br />26.5% <br />7884 36% <br />Mu ins/LT <br />20,650 <br />15,200 <br />37.1% <br />6560 30% <br />North Fork <br />17,520 <br />13,270 <br />32.4% <br />6552 30% <br />Rowell <br />2,230 <br />1,700 <br />4.1% <br />936 4% <br />Totals <br />54,510 <br />41,020 <br />100% <br />17,700* 100% <br />Based on the basin response parameters utilized in the model: <br />Percent of total rainfall to run off — 75.3% <br />Average percent Infiltration — 24.7% <br />Peak Discharge at station 23120.01 (just below X Bar 7 Ranch) — 17,700* cfs <br />(*cumulative peak discharge is lower and the sum of the peak discharges due to differences in timing <br />of the basin flows relative to each other) <br />Peak Stage (water depth) at station 23120.01 (just below X Bar 7 Ranch) = 14 feet <br />Little Thompson River Sept 2013 Flooding - Fact Sheets 3/29/14 <br />Public Meeting, Lyons, CO Page 2 of 4 <br />