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<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />.' <br />I <br />I, <br />I <br />1 <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />002l:J6 <br /> <br />3.0 RESULTS <br /> <br />A total of twenty-two erosion sites were identified as a result of the soil erosion survey. <br />Erosion was observed on all shores of the Williams Fork Reservoir (north, east, south, <br />and west), as well as the on the Williams Fork River as it flows into the reservoir. A map <br />illustrating the location of each erosion site within the FERC project boundary is <br />provided in Appendix B. Approximately 29% of the reservoir edge was experiencing <br />erosion activity at the time of this survey, Most of the erosion sites are located on the <br />southern and western portions of the reservoir edge, where small peninsulas extend into <br />the reservoir. <br /> <br />No erosion sites were identified on upland areas within the FERC project boundary, and <br />as a result all but one (95%) of the erosion sites were reservoir bank; the other erosion <br />site (ER02-1718) was identified with a site type of stream bank. This erosion site is <br />located along the Williams Fork River as it flows into the reservoir. Based on the <br />similarity of erosion site types observed, it would be expected that the classification of <br />these erosion sites would also be similar. In fact, 86% (nineteen) of the erosion sites are <br />bank cut. One site (5%) was classified as bank cut/sheet, and two (9%) were gully, <br /> <br />The bank cut Isheet erosion site (ER02-1706) is a particularly unique feature located at <br />the tip of a peninsula extending into the reservoir. It appears that this site was originally <br />a bank cut site exclusively. However, as time passed and the reservoir waters continued <br />to cut into the upland areas, the height of the bank decreased, Eventually, reservoir water <br />flowed over the top of the bank and began eroding topsoil via sheet erosion. Although <br />the current form of erosion taking place is classified as sheet, evidence of bank cut <br />erosion occurring in the past does exist at this location, The two gully erosion sites <br />(ER02-1713 and ER02-1714) are a result of overland vehicle activity. They are located <br />within dirt roads that extend down the reservoir bank to the beach, As water flows down <br />these roads, it creates well-defined channels down the length of the road. Water from <br />these channels eventually flows into the reservoir. The intensity of erosion in these areas <br />may increase if vehicle use continues. <br /> <br />Not only are a high percentage of the erosion sites similar with respect to location, site <br />type, and classification, but thirteen of the twenty-two sites (60%) had sand as a major <br />component of its soil. This would be expected in erosion sites, as sandy soils are <br />typically easily broken down and eroded, Of the nine erosion sites not composed <br />primarily of sandy soil, five (23% of total) were dominated by clay. Two (9%) sites had <br />a soil composition of clay with small gravel, and three (14%) erosion sites were <br />composed of clay with chunks of mudstone. The remaining three erosion sites varied <br />greatly with respect to dominant soil type. Two (9%) were composed primarily of cobble <br />greater than 12 inches, one (5%) was dominated by fractured bedrock, and one (5%) was <br />composed of river gravels, <br /> <br />All but one (95%) of the erosion sites were active. ER02-1706 was the only inactive <br />erosion site observed, This erosion site was classified as bank cut/sheet, and its <br /> <br />Willlllrru; Furk Reservoir <br />Hydmdect'ric Projec, <br />January 2004 <br /> <br />Steigers Curporation <br />Erosion Survey Repul1. <br /> <br />Page 5 <br />