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The Larimer County Canal is predominately earth-lined. Approximately one-quarter mile of the <br />canal has been lined with a mix of concrete and geo-textile liner. WSSC maintains the good <br />condition of the Larimer County Canal through annual maintenance which includes burning of <br />the canal, replacing of headgates as needed, and preventing erosion through the placing of rip- <br />rap. <br />Length: Approximately 58 miles of main canal, not including extending laterals. <br />Capacity: The approximate capacity at the upper end of the canal is 750 cfs. <br />Conveyance Efficiency: In 1990, Rocky Mountain Consultants (RMC) performed a study on <br />seepage in the WSSC System. Over a 1950 to 1985 study period, a total system loss on <br />the Larimer County Canal and plains reservoirs was estimated which included ditch <br />seepage, reservoir evaporation, and miscellaneous losses occurring prior to delivery to <br />farm headgates. The study showed an average system loss in the Larimer County Canal <br />of 14 percent. Additional ditch losses were also determined for the Pierce Lateral and <br />Collins Lateral at 12.5 percent and 5 percent, respectively. The study goes on to report <br />that it is the opinion of RMC that the loss estimates for the laterals are conservatively <br />high and may tend to overestimate ditch losses. <br />In a separate study performed by Wright Water Engineers in September 1964 it was <br />estimated that total water losses to WSSC below the Larimer County Canal headgate over <br />the 1952 to 1963 study period amounted to 25 percent of the deliveries. The total losses <br />estimated in the Wright Water Engineers study included losses due to evaporation, non- <br />beneficial consumption by phreatophyte plants immediately adjacent to the canals and <br />reservoirs, and seepage loss from the canal and associated reservoirs. System losses in <br />the Wright Water Engineers study were found to be influenced by climatic variation, with <br />considerable reductions in losses during average and wet years. It is not clear if this <br />study considered individually-run C-BT water or deliveries to non-WSSC laterals <br />extending beyond the Larimer County Canal. Inclusion of the lateral losses would result <br />in a similar loss estimate as determined in the RMC report. <br />Irrigated Area: Ina 1968 report on the Long Draw Reservoir Enlargement Project prepared by <br />Wright-McLaughlin Engineers and Woodward-Clyde & Associates it was reported that <br />the WSSC comprised an area of 53,859 acres, of which 37,425 acres were being irrigated <br />in 1967. In 2001, WSSC reported irrigated area under the Larimer County Canal of <br />46,300 acres. <br />The distribution of irrigated crops associated with the 1968 Long Draw Reservoir <br />Enlargement Proj ect was as follows: <br />Percent of Irrigated <br />Crop Acres in 1967 <br />Barley 8 <br />Oats 5 <br />Wheat 2 <br />WaterSupply&Storage Memo.doc <br />11 of 21 <br />