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<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />reservoir was used for the temporary storage of water derived from water ri~~hts in the <br />Greeley No.2 Canal. Seeley Lake RHservoir was awarded priority No. 60 for the storage <br />of irrigation water on or around OctobBr 1909. In normal years the reservoir remains near <br />capacity as OILC has water rights dimctly from the Cache la Poudre River and only uses <br />the water in Seeley Lake when these rights are not available. <br /> <br />A copy of the decree for storage is provided in Appendix C. <br /> <br />NEED FOR THE PROJECT <br /> <br />Seeley Lake Reservoir is currently not under any storage restriction by the Office of the <br />State Engineer. Several years ago a sink hole opened near the county road at the <br />downstream toe of the dam. This put the condition of the outlet pipe into question. OILC <br />purchased ductile iron pipe and contacted a contractor to repair the outlet pipe downstream <br />of the gate tower without proper approval from the SEO. The work was halted and OILC <br />contacted Smith Geotechnical to provide engineering services. Initially SEO approved the <br />replacement of the outlet pipe downstream of the gate tower in October 2001. Before <br />construction started the owner decided to address other problems with Seeley Lake. <br /> <br />Seeley Lake Reservoir has a service spillway incorporated into the gate structure. A low <br />area to the east of the dam has historically been considered the emergency spillway. In <br />1976 the SEO performed an in-house hydrology study to determine the dischar~~e capacity <br />of the combined spillways. It was determined the spillways were inadequate. OILC <br />contracted with an engineer to design an emergency spillway. It appears the work was <br />performed, but never submitted to the SEO and construction never occul"red. The <br />proposed replacement of the outlet pipe caused the SEO to bring up the spillway issue <br />again. The owner decided to incorporate the construction of the emergency spillway into <br />the repair of the outlet pipe, and Smith Geotechnical was again contacted. A new design <br />was submitted to the SEO including a new emergency spillway. Along with the repair of <br />the outlet pipe, a new gate tower incorporating a service spillway was designed. The new <br />design has been submitted to the SE.O and is nearing final approval for construction. <br /> <br />EXISTING FACILITIES <br /> <br />Photographs of the reservoir and gate structure appear in Appendix A. The dam crest is <br />approximately 1500 feet long with upstream and downstream slopes of 3 to 1. The vertical <br />height of the dam is approximately 18-feet, which is the depth from the dam crest to the <br />pipe invert. The dam height above the natural ground at the downstream toe' and <br />throughout most of the dam is only approximately 5-feet. Most of the lake stora~Je is due to <br />a natural depression and the ground level is well above the upstream outlet conduit invert. <br />, The dam outlet was placed in an excavation at an elevation lower than the surrounding <br />area at the dam. Due to this, an inlet structure was placed out into the lake approximately <br />150 feet from the dam toe. This structure is tied to the gate control tower with a pipe and <br />makes it possible to drain the reservoir even though the surrounding area downstream of <br />the dam is higher than the reservoir bed. <br /> <br />Rehabilitation of Seeley Lake Outlet - Feasibility Study <br /> <br />Page 5 <br />