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<br />Fish Creek Reservoir Expansion EIS <br />S:W:':'~:"AA:r:::..':r:=;:;:;::::->>*:,>>::::;:-~ffi::r::~~,~l?::;:.;"t.:.--:::W'''::;:;:-;$~~':;:;:;~A~.;,%'':";::::::::~~~~~*.<<w....'w-::;:.;~;$;.;~'::<JZi::~:::;:;&=:::.:.:T~~; <br /> <br />Temporary water quality impacts at the site could occur during construction activities in the form <br />of increased sedimentation. Best management praCtices, however, would be utilized during <br />construction to minimize erosion, sedimentation, and the subsequent increase in stream turbidity and <br />suspended solids. Additionally, stream monitoring would be required. During construction, there <br />would also be the potential for petroleum based contamination from heavy equipment leaks and/or <br />spills. A spill prevention and response plan would be required within the construction operating <br />plan. <br /> <br />Under Alternative B, the erosional process in Puppy Dog Lake drainage would be reduced. This <br />would result in a decrease in downstream sedimentation. <br /> <br />With the implementation of Alternative B, the existing vault toilet, which is no longer functional, <br />would be replaced with a composting toilet. Utilization of a composting toilet would protect the <br />water quality of the reservoir by preventing the introduction of untreated wastewater. <br /> <br />Under Alternative B, approximately 50 acres of land would be inundated. Most of this area would <br />be within borrow areas, and thus would not be vegetated at the time of inundation. Small areas of <br />vegetation, however, would be inundated. Given the short growing season at the reservoir site, the <br />existing highly oxygenated, high quality water source, and the minor extent of vegetation to be <br />inundated, water quality impacts associated with inundation are expected to be negligible. <br /> <br />Cumulative water quality impacts are discussed in Section 4.3.3. <br /> <br />4.3.2.3 Alternetive C . Smallar R8Servoir Expansion <br /> <br />Physical Characteristics - Alternative C would be a 908 AF expansion of the existing Fish Creek <br />Reservoir. The total capacity of the small scale reservoir would be 2,750 AF covering 112 acres (an <br />increase in surface area from the existing reservoir of approximately 22 acres). The main dam length <br />would be 750 feet (an increase of 100 feet), and the height would be 63 feet (an increase of 8 feet). <br />The saddle dam would be increased in length to 800 feet from 400 feet, and the height would <br />increase to 26 feet from 10 feet. Water supply from the Upper Middle Fork of Fish Creek and <br />Granite Creek would be sufficient to fiU the small scale enlargement during average years, as well <br />as the 25-year low flow period. <br /> <br />Construction Plan - The construction plan for Alternative C would be the same as for Alternative <br />B. Two construction seasons would still be required, and a diversion structure for the Upper Middle <br />Fork of Fish Creek and Granite Creek would be required during the first construction season. <br /> <br />Operation Plan - The operation plan for Alternative C would be the same as for Alternative B, <br />resulting in a decrease in erosion and sedimentation impacts in the Puppy Dog Lake drainage from <br />the current reservoir operation. <br /> <br />Water Rights - The additional storage capacity of Alternative C is 908 AF. This additional amount <br />of storage could be exercised under the conditional storage right of 2,000 AF. Eventually, however, <br />the City would lose the remainder of this conditional storage right. The stipulated agreement <br />between the City and CWCB would not be pertinent since the additional 200 AF storage right <br />would not be exercised under this alternative. <br /> <br /><.w..;::;?i:::-m~::i.~~~~~~:W.;:;..:.."~'&'::l;;~::::::;::::;:;~-W;:;$;.%~0..0::::~;:;::::f:<z:z':::~::&.:,..~:t:.:.m~'-?:<:::;:.x.:'l~ <br /> <br />P.ge 4.10 <br /> <br />September 1993 <br />