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l'1")'~ ~?? u _..;....0.4 Affected Environrnent & Consequences 3. to ) c' It should also be noted that operation of the proposed AB Lateral facility results in a more natural hydrograph downstream from the Tunnel. Prior to Aspinall construction, winter flows on the Gunnison were typically 200 to 500 cfs; Aspinall operation artificially increased these to the 1000 to 2000 cfs level. " Y; 3.3 Irrigation Systems The UVRP is one of the oldest irrigation projects in the United States and irrigates more than 80,000 acres of land. Seven small dams divert water from the Gunnison and Uncompahgre Rivers and convey flows to irrigated fields through several hundred miles of canals, laterals, and drains. Water diverted and not consumed is returned to the Uncompahgre and Gunnison Rivers. The UVWUA operates the UVRP. '-, 3.3.1 Existing Conditions The South Canal, the principal conveyance for transporting flows from the Gunnison River into the Uncompahgre River, begins at the West Portal of the Tunnel and runs southwesterly about 11,4 miles to the Uncompahgre River. Its maximum carrying capacity is 1,010 cubic feet per second (cfs) at the upper end while near its outlet at the Uncompahgre River, it is slightly more than 900 cfs. Upstream of the proposed AB Lateral tailrace, there are 3 major canal systems. The West Canal is supplied by the South Canal and conveys irrigation flows to about 7,500 acres west of the Uncompahgre Riverc Mean monthly flows into the system typically range from 170 to 180 cfs. The Montrose and Delta (M&D) Canal is approximately 40 miles long and diverts flows from the Uncompahgre River to more than 25,200 acres on the west side of the Valley. Maximum flows into the system range between 550 and 560 cfs. Included with the Montrose and Delta diversions are flows that are ultimately used by the Ironstone Canal. These flows are diverted into the M&D because a flow restriction on the Ironstone. The Ironstone's diversion works on the Uncompahgre River does not allow carriage of all flows required further downstream. The Ironstone flows are carried via the M&D, and are delivered to the Ironstone system through Coal Creek. The Loutzenhizer Canal, nearly 15 miles long, diverts water from the Uncompahgre River about 2 miles downstream from the M&D Canal headgates. This canal serves about 6,200 acres on the east side of the Valley near Montrose. There are four major canal systems downstream from the proposed Project tailrace. The Selig Canal diverts water from the Uncompahgre just north of Montrose and runs 20 miles to the north, irrigating approximately 10,000 acres on the east side of Valley. The diversion dam for the Ironstone Canal is located a few miles south of Olathe. The AS Lateral Hydropower Project July 2000 ; '" jl' :j < ,~,Jl ", c"lL.lii "'c,~"~,Ji;"