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I I I I I I I I I I I I I I I I I I I The Nunn-Fort Collins Ulm soils are deep, nearly level to moderately sloping, well drained clay loams and loans formed in alluvium: on fans and side slopes. The Otero-Nelson-Tasssel soils are shallow to deep, nearly level to moderately steep, well drained sandy loams that formed in materials weathered form sandstone in alluvium modified by wind on uplands and fans. The precipitation in the Loveland area averages approximately 12.0 inches, the average afternoon relative humidity is about 40 percent in summer, the average summer temperature is 87 degrees, and the average snowfall is 40 inches. The length of the growing season in the area is approximately 140 days with the average for the last killing frost in the spring being May 10 and the first killing frost in the fall being September 30. LAND OWNERSHIP The land irrigated in the project service area includes private farms, ranches, public parks, golf courses, and cemeteries. NEED FOR THE PROJECT The Louden Irrigating Canal and Reservoir Company, Inc is undertaking this project to meet the requirements of the State Engineer's Office for dam safety. The reserv~ir is currently restricted to GR 10.0' due to seepage problems. The repair will allow full storage to GH 12.4' for an increase of 150 acre-ft of storage, and will allow LICRC to continue to provide irrigation water to its shareholders to irrigate their crops. The Rist-Benson Reservoir Dam and associated structures were constructed in the early 1900's. The dam is approximately 1,450 feet in length, has approximately 2 to 1 upstream and downstream slopes with a crest width of 16 feet and a maximum structural height of approximately 20 feet. The dam is located on the south and west sides of the reservoir with the outlet located on the south side. The dam embankment has experienced seepage problems since the height of the embankment was increased in 1932. To help in limiting seepage the dam has been excavated and recompacted twice, between Sta. 14+25 to 21+00 in 1993, and between Sta. 10+70 to 14+25 in 2001. Therecompacted sections of the dam have had limited the seepage from the dam since the recompaction was completed. Between Sta. 21 +00 to 24+93 the dam embankment has not been recompacted and seepage is seen along the downstream toe when the reservoir is raised above the GH 10.0' height. Due to the seepage seen when the reservoir level is above OH 10.0' the Office of the State Engineer has placed a fill restriction on the dam limiting the reservoir elevation to OR 10.0'. The upstream face of the sections of the dam where recompaction has occurred, Sta. 10+70 to 21 +00, is protected against erosion by using riprap protection from the upstream toe to the crest of the dam as required by the Office of the State Engineer. Where the dam has not been recompacted, Sta. Rist-Benson Feasibility Study Page 6