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<br /> - 4 - <br />to identify flood easement boundaries a full topographic survey of the reservoir <br />was conducted in April of 2013. <br /> <br />Surprisingly, the survey revealed that the reservoir has a larger capacity than <br />shown by both the initial 1889 survey and the1920 enlargement survey. The <br />decreed storage volume for the reservoir is 1781 acre feet at gauge height 22 <br />feet. What the 2013 survey shows is that the reservoir has a storage capacity of <br />2098 acre feet at this level. However, 202 acre feet of this storage are dead pool <br />storage that could only be removed from the reservoir by pumping. <br />Consultations with the Water Commissioner and Dam Safety Engineer indicate <br />that this storage can be either included or excluded in the total storage <br />calculations. If the dead pool storage is included in the storage volume, the <br />reservoir would have full storage capacity at approximately gauge height 19 feet. <br />If the dead pool storage is excluded the reservoir would have full storage <br />capacity at approximately gauge height 21 feet. <br /> <br />If the storage level was limited to gage height 19 feet the impact on privately held <br />land around the reservoir would be significantly reduced, particularly on the five <br />ten-acre lots bordering the reservoir in the subdivision to the north and east. <br />With the normal storage level at gauge height 19 feet and allowing for three to <br />four feet of freeboard on the dam, flood easements would be needed on small <br />portions of five of the subdivision lots. Alternatively, with a minimal amount of fill <br />and grading on these lots the required flood easement line could be moved onto <br />NPIC land and no long term flood easements would be needed. With the normal <br />storage level at gate height 19 feet water can be contained within NPIC owned <br />lands on all but a small portion of the land owned by the McChesney’s to the <br />south. This area could also be filled moving both the normal storage elevation <br />and the flood boundary line onto NPIC land <br /> <br />Lowering the storage level to gauge height 19 feet would move the high water <br />line into the midst of the cottonwood grove on the southwest side of the reservoir. <br />It would then be possible to save a portion of the trees above the normal storage <br />line if the age and condition of the trees justifies salvaging them. Water <br />consumption of these trees should also be considered. Studies of the <br />evapotranspiration rates of cottonwood trees show that the rate is dependent <br />upon proximity to ground water, temperature, wind velocity, and tree size. Given <br />that these trees are large mature trees in a warm, windy area close to <br />groundwater it can be assumed that they are consuming water at a high rate <br />during the summer months. No specific studies have been completed in this <br />area but other studies indicate that mature trees can transpired an average of <br />200 gallons per day. Assuming this rate for six months each year the 400 trees <br />around the reservoir would consume 44 acre feet of water per year. <br /> <br />An alternative to lowering the normal storage level to gauge height 19 feet is to <br />exclude the dead pool storage from total storage and set the normal storage level <br />at 21 feet. Major advantages to this alternative include use of the full decreed