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2.05.6(6) <br />The Terror Ditch is an unlined earthen structure with a capacity of about 6 to <br />8 cfs. The Ditch delivers irrigation water to Garvin Mesa. The first 2,500 feet <br />of the ditch is constructed along a very steep hillside above Terror Creek. <br />This section of the ditch was constructed by pioneering a road into the <br />location of the headgate and then excavating the ditch along the inside of the <br />road. Once the ditch emerges onto Garvin Mesa it splits into various laterals <br />and delivery ditches. <br />Bruce Park Dam consists of a main dam and a saddle dam. The original <br />dam was constructed in the 1940s. The dam was raised to a reported <br />structural height of 58 feet between 1950 and 1952. The reservoir has a <br />reported storage capacity of 598 acre-feet with a water surface area of 33 <br />acres. The outlet works consists of a 14-inch diameter, welded steel pipe <br />with a reinforced concrete encasement. The intake to the outlet works is a <br />hand operated hoist slide gate. In 1990 Bruce Park Dam was re-classified <br />as a Class I (high hazard) dam. The Operator recognizes that the Bruce Park <br />Dam and Reservoir is under a Forest Service Special Use Authorization to <br />Terror Creek and Reservoir Company. <br />The Bruce Park landslide is located on a southeast facing slope with <br />grades of about 15 to 20 percent dipping into the reservoir. An existing <br />road is located in the lower portions of the slide adjacent to the reservoir <br />and several ditches cross the slide area. The slide area is covered with <br />grass, weeds and bushes and is generally devoid of trees. The <br />topography is hummocky and vegetative growth indicated that water <br />ponds in several areas of the slide and/or springs may be observed during <br />spring runoff. The landslide materials consist of low to high plasticity clay. <br />Materials with high fine contents (passing No. 200 sieve), especially clay <br />fines, are at low risk for liquefaction. Based on test results, the fine <br />contents in the landslide materials are in excess of 70 percent indicating <br />low susceptibility to liquefaction. The estimated the landslide volume <br />(volume of solids and volume of water) is about 1.5 to 2.0 million cubic <br />feet. (YEH Final Geotechnical Investigation and Evaluation Report Bruce <br />Park Landslide, April 5, 2006, revised November 6, 2006) <br /> <br />PR-11 <br />2.05 - 103 - 11 /08 <br />/~ PPRovE~ <br />I ~~ l9/b 8 <br />