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<br />Feasibility Study <br />Mariano (Boedecker) Reservoir Dam Rehabilitation <br />September 2001 <br /> <br /> Table 1 <br /> Consolidated Home Supply Ditch and Reservoir Company <br /> Mariano Storage Rights <br />Water Right Appropriation Adjudication Amount Administration Comment <br />Date Date (ac-ft) Number <br />Mariano Reservoir Aug. 1, 1888 Mar. 22, 1890 5,570.70 14093.00000 aka, Boedecker Lake <br />Mariano Reservoir Refill once a year, <br />Refill Jun. 17, 1907 Nov. 14, 1939 5,570.70 29675,20986 George Rist Ditch <br /> 195 cfs <br /> <br />The Company has consistently exercised the Mariano storage right, filling the reservoir during the winter <br />and spring and discharging during the irrigation season, Appendix B presents the monthly diversion <br />records for Mariano Reservoir, <br /> <br />Pro;ect Description and Alternatives <br /> <br />The purpose of this project is to repair the earthen embankment dam to provide safe water storage, The <br />repair work needed to provide sufficient structural integrity is rather straight forward, Thus, the <br />alternatives evaluated are limited to the following: <br /> <br />1. No Action <br />2, Construction of a toe drain and downstream toe berm ($1,048,000) <br />3, Complete dam reconstruction ($3,600,000) <br /> <br />Alternative 1, No Action <br /> <br />This alternative was considered unacceptable due to the loss of storage within the reservoir. Storage loss <br />would occur, as the safe storage level of the reservoir would be significantly lower without rehabilitation <br />efforts to strengthen the dam, The total storage is reported to be 5,570 acre-feet at gage height 23,6, This <br />gage height equals the spillway level. At this normal high water line, the water surface area is 371 acres, <br />An area-capacity curve is provided in Appendix G, Because the reservoir basin is broad and shallow with <br />a gently sloping bottom, the majority of active storage is provide in the top 10 to 15 feet. Restricting the <br />allowable depth of storage will have a substantial impact to water available for use during irrigation. <br /> <br />Alternative 2, Construction of a Toe Drain and Downstream Toe Berm <br /> <br />This alternative involves the construction of a toe drain and construction of a toe berm, This alternative <br />also includes foundation grouting to help control seepage, Outlet modifications to extend the outlet past <br />the proposed toe berm and line the 100+ year old masonry arch outlet are also included as part of this <br />alternative, This alternative consists of economical construction techniques which are commonly <br />employed to repair seepage and downstream slope instability. This alternative will allow full reservoir <br />storage and is considered the preferred alternative, <br /> <br />Alternative 3, Complete Dam Reconstruction <br /> <br />This alternative was ruled out as it would increase the cost of the project significantly and increase the <br />time required to conduct the construction, with little added benefit. <br /> <br />-2- <br />