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I I I I I I I I I I I I I I I I I I I Project Description The purpose of this project is to provide a means for the PRCC to continue providing irrigation water to shareholders while minimizing the occurrence of future disruptions of water flow. Four alternatives were considered: 1. Reline the existing tunnel. 2. Open up the tunnel by removing the overburden. 3, Relocate the canal approximately 150 feet west of the existing canal (tunnel) and lay six-foot diameter reinforced concrete pipe, 4, No action, Alternative No.1 would involve relining the entire 600 feet of tunnel with treated timbers. Based on past experience of relining 100 feet of this tunnel, the total cost of this project is estimated at more than $500,000, In addition to the considerable cost to do the work, finding a contractor to do the work is problematic, and in the end, the Company would still have a tunnel with treated timbers and its attendant problems, This alternative was eliminated due to cost, and because it did not provide a permanent solution to the problem. Alternative No.2 would involve moving power utility poles at an estimated cost of $60,000, removing the overburden from the tunnel and disposing of the excavated material at a cost of $300,000, This alternative was eliminated due to cost, and because it is not desirable to the State Highway Department. Alternative No.4 would result in continually increased maintenance costs and the very real likelihood of portions of the tunnel collapsing and depriving shareholders of irrigation water and substantially reducing their farm and ranch income, The risks associated with this alternative are not acceptable to the PRCC Board of Directors. (See Economic Analysis portion of this study.) The selected alternative, Alternative No.3, involves the construction of a new canal approximately 150 feet west of existing tunnel and laying six foot diameter reinforced concrete pipe for a distance of approximately 700 feet, bypassing the tunnel entirely. The pipe will have an inlet and outlet structure and is designed to carry 200 cfs with extra capacity allowing for 25-year storm flow, The pipe will be designed for open channel flow and will have a trash rack at the entrance of the pipe. Engineering designs and cost estimates for the project have been prepared by the La Plata County Office of the Natural Resources Conservation Service (NRCS). Preliminary plans as prepared by the NRCS are attached in the back pocket of this study, Pine River Canal Company Tunnel Hill Project Feasibility Study January 1999 Page 11 of 15