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Harry Ranney -2- October 20, 1994 <br />primary discharge tube, after having taken transit readings of various pond features. The <br />following are my revised elevations: <br />Top of embankment <br />Top of emergency weir <br />Top of primary <br />Bottom of pond <br />Map C-13 Elevation <br />7501 <br />7500 <br />7498.21 <br />7492.5 <br />Revised Elevation <br />7391 <br />7390 <br />7387.5 <br />7382.5 <br />I used the curve numbers of 73 for north-facing undisturbed areas and 86 for the yard area, <br />since these are the values the Division suggested the operator use (See Kent's memo to you, <br />dated December 9, 1993). I used a total area of 21.6 acres rather than the 24.6 acres the <br />operator used. The east side diversion ditch reduced the land area draining to the west pond. <br />My Sedcad run calculated a yearly sediment load of .13 acre-feet, rather than the .OS acre- <br />feet used in the operator's design. My pond elevation-capacity figures were very close to <br />the operator's figures. My calculations show a pond capacity, up to the top of the <br />emergency spillway weir, of 1.82 acre-feet, as compared to 1.864 acre-feet that the operator <br />obtained. <br />For the east pond, I, again, attempted to correlate map C-4 elevations with map C-13 <br />features. However, the transit readings that I had obtained showed that the elevation of the <br />top of the emergency spillway weir of the east pond was 2.05 feet lower than the elevation of <br />the top of the emergency spillway weir of the west pond. The operator's figures on map C- <br />13 show a difference of 3 feet. I used my Figures. Also, I changed the elevation of the <br />primary discharge structure., based on the transit data. The following are my revised <br />elevations: <br />Map C-13 Elevation <br />Top of embankment <br />Top of emergency weir <br />Top of primary <br />Bottom of pond <br />7498 <br />7497 <br />7493.81 <br />7485.5 <br />Revised Elevation <br />7389 <br />7387.95 <br />7386.15 <br />7376.5 <br />The volume of water entering the east pond due to the runoff from back to back 10 year - 24 <br />hour and 25 year - 24 hour events was calculated to be .27 acre-feet by me and .21 acre - <br />feet by the operator. The sediment volume was .01 acre-feet in the operator's designs and <br />