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I I I I I I I I I I I I I I I I I I I 2. Problem Areas. rehabilitate the two of deficiencies. There are several problems which contribute to the need to dams that form Reservoir No.6. Following Is a general Ilst 1. Inadequate freeboard to allow fllllng to the maximum decreed gage height. 2. Severely deteriorated outlet conduit and operator. 3. No spillway. 4. Seepage problems on the main dam at the outlet ditch. 6. Inadequate to nonexistent upstream slope protection. 6. Locally oversteep face slopes In certain areas. 7. No energy dissipation structure. Due to the poor condition of the outlet works and no emergency splllway, the State Engineer has placed a restriction on the dam requiring no storage In the reservoir. Because of the deteriorating conditions and the current storage restriction, the owner Is losing up to approximately 10,000 acre-feet of storage per year. The restrictions at this time do not greatly affect the operation of the North Poudre system as only 640 acres can be irrigated out of NO.6. However, the owner Is concerned with the lost revenue that could be generated from the use and or sale of the water. There is also some concern about the possibility of losing a portion or all of its water right were another water user to file a challenge to their use and future right to store. The loss of 10,000 acre-feet of water that possIbly could be exchanged wIth another entity hIgher up In the basin could have a major Impact on the North Poudre shareholders and the crops they produce In a dry year. 3. Proposed Improvements. In order to restore the reservoir to full utilization, It Is necessary to reconstruct and repair major portions of the dam. Both the upstream and downstream faces need to be reworked to a uniform slope. The crest of the dam must be raised approximately 3 feet to provide adequate freeboard; a new outlet works needs to be installed; rlprap and rlprap bedding must be placed on the upstream slopes; a toe drain must be Installed at the toe of the main dam and outlet channel to control the underseepage; and a spillway must be constructed that will pass a minimum of 75% of the Probable Maximum Flood (PMF) as required by the State Engineer's office for a Class I, Intermediate size dam as outlined In Rule 6 of The Rules And Ref(u!atlons For Dam Safety And Darn Construction. A more detailed description of the proposed Improvements and structural plans is Included In Article A.7. of this chapter. A.2. GEOTECHNICAL INVESTIGATIONS. The geologic and geotechnical Investigations are described In Appendix D. These Investigations were conducted In 1979 by Chen and Associates for Bruns Engineering. The plan of development Is based on their data and additional drilllng, sampling, and testing wlll have to be conducted prIor to final design to verify the Information. PAGE 2 Chapter V - Yo. 6 FeulbUlty