C150125 Approval Letter - Laserfiche WebLink

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Surface Creek Ditch & Reservoir Company - Dam Rehabilitation November 25-26, 2002 Agenda Item 20c unsuitable material and investigate seepage areas. In January 2002, as a result of removal of the entire downstream shell of the embankment, the SEO issued a zero storage restriction until all repairs are completed. A significant amount of unsuitable material and voids were discovered in the dam, resulting in almost a complete rebuilding of the dam. Dam repairs have been progressing under the approval and oversight of the SEO, based on design plans and specifications prepared by Resource Engineering, Inc. of Glenwood Springs. Temporary construction financing is being provided by the Surface Creek Bank in Cedaredge. Feasibilitv Studies The SCD & RC through its President, Ellis Fritchman and Secretary, Chuck Richards has completed the feasibility study in accordance with CWCB guidelines. The study includes a recommended alternative available for dam rehabilitation. The engineering design and cost estimate have been provided by Resource Engineering, Inc. of Glenwood Springs. Surface Creek Ditch and Reservoir Company The SCD & RC is a Colorado mutual ditch company and non-profit corporation registered in the State of Colorado, in good standing. The Company was incorporated in 1886. There are 255 shareholders holding 810 shares of stock. The SCD & RC exists in perpetuity and sets annual assessments that are assigned to the stockholders according to the number of shares they own. It also holds the power to refuse to deliver water to shareholders who fail to pay their assessments, and the power to offer shares for sale to pay for unpaid assessments. The Board of Directors has the authority to incur debt as they deem necessary to carry out the purposes of the company. Water Rights The SCD & RC owns and operates a system of 18 reservoirs, and delivers on the average 8900 ac-ft per year. Hotel Twin has a water right to store 436.31 acre-feet, based on 1907 and 1937 decrees. Proiect Description Based on recommendations by Resource Engineering, Inc. (July 2002) the dam is being rebuilt essentially from the ground up. It is a fairly typical dam rehabilitation design, in that it will include a chimney drain and blanket drain to provide controlled collection and conveyance of seepage water within the dam, and a toe drain to provide controlled discharge of the seepage water. The USFS has a road over the top of the dam that is being widened from 24' to a 30' paved width (two 11' lanes with 4' shoulders). The USFS is sharing in the cost of the project as the dam is an integral part of their road system, and Delta County is providing in-kind work. The dam embankment will be enlarged by 22' to have a crest width of approximately 44 feet, with the road shifted off of the dam embankment on the downstteam side. The existing outlet works is being retained but extended through the new embankment, and a new concrete outfall structure and riprap channel constructed. A new 36" service spillway pipe (with a 1 OO-year design) is being installed, and the emergency spillway is an area on the east embankment where water would flow over the roadway in a controlled manner. Engineering plans have been approved by the State Engineer's Office, and they are confident that all unsuitable materials have been removed. Seepage has always been the big concern with the dam, and the results of the geo-technical investigation resulted in a clear design imperative to rebuild the dam. With serious structural concerns, other possible alternatives such as lining the upstream Slope were not considered viable. Page 2 of 5