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Ms.Amy Eschberger <br /> RE: Treiber Lakes M-2011-049 <br /> December 1, 2021 <br /> Reclamation Plan <br /> The Treiber Lakes site final land use is currently permitted for developed water resources and <br /> includes construction of lined below-grade reservoirs. This Technical Revision does not propose <br /> changing the permitted final land use. As illustrated on the revised Exhibit F-1,Reclamation Plan, <br /> the purpose of this Technical Revision is to add existing and proposed reservoir infrastructure to <br /> the overall reclamation plan. The primary aspect of the site reclamation that creates the final land <br /> use for developed water resources, slurry wall construction, was included in the original approved <br /> reclamation plan and has been completed. <br /> Slurry Wall Construction. The Treiber A and Treiber B slurry wall construction was completed in <br /> 2013 and 2016, respectively. The Colorado State Engineer's Office approval letters for each <br /> reservoir_are included in_Altachmetit A. _ <br /> Cache la Poudre Riverbank Stabilization. The Colorado Front Range flooding of September 2013 <br /> included flooding within the Cache la Poudre River basin. Although the river did not overtop the <br /> Treiber Lakes site banks, significant riverbank erosion was observed in two specific reaches <br /> adjacent to the recently completed Treiber A slurry wall. Emergency action took place in 2014 to <br /> repair and stabilize the affected embankment reaches. Stabilization included embankment grading, <br /> boulder toe protection, graded riprap embankment cover, and willow staking. All local, State, and <br /> federal permits for floodplain and waters of the U.S. work were obtained prior to construction. <br /> Design plans for the stabilization activities are included in Attachment B. <br /> Treiber A Interconnect Structures. To facilitate water transfers to and from the Treiber Lakes site <br /> reservoirs,in 2014-2015 interconnect piping was installed on the east and south sides of Treiber A. <br /> The interconnect piping connects Treiber A to the Overland Ponds Complex Pond B (M-2002-081) <br /> to the south and Treiber B reservoir to the east. The design report, plans, and an as-built survey <br /> are included in Attachment C. During preparation of the interconnect report and design, borelogs <br /> and laboratory test were conducted and hydraulic and structural calculations were performed. <br /> Although not included in Attachment C, these tests and calculations are available upon request. <br /> All local permits and right-of-way agreements were obtained prior to construction. <br /> Treiber B Outfall Structure. Again, to facilitate water transfers to and from the Treiber Lakes site <br /> reservoirs, in 2020 a gravity outfall structure was constructed in the northeast corner of Treiber B <br /> reservoir. The structure takes advantage of a pre-existing outfall to the Cache la Poudre River to <br /> deliver water from the reservoir to the river. All applicable local, State, and federal permits for <br /> floodplain and waters of the U.S. work were obtained prior to construction. As-built drawings of <br /> the structure are included in Attachment D. <br /> Treiber A Intake Rundown. As noted in the DRMS report from the May 26, 2021, Treiber Lakes <br /> site inspection, significant erosion gullies and ruts have developed along the north shoreline of <br /> Treiber A. The erosion gullies are the result of water being pumped from the Cache la Poudre <br /> River to the reservoir. Discharge of water into the reservoir has created significant headcutting <br /> along the reservoir embankment and if not addressed,could result in impacts to the slurry wall. To <br /> correct the problem, when the water level in Treiber A is lowered in the spring of 2022, the <br /> Page 2 of 4 <br />