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I I I I I I I I I I I I I I' I I I I I 002H4 water flowing through the site, and observation of waves from the reservoir impacting an erosion site. The presence of only one of these parameters was necessary to conclude active site status. Inactive sites showed no signs of recent erosion, and no erosion activity was observed during the survey, Classification of Erosion Type (Sheet, Rill, Gully, Bank Cut) Each erosion site was classified as sheet, rill, gully, or bank cut erosion according to the definitions provided in the Soil Conservation Service Soil Survey Manual (1993)1. Sheet erosion is the uniform removal of soil from an area without the development of water channels, The removal of soil through the cutting of many small water channels is rill erosion. Gully erosion occurs when water cuts defined channcls down into the soil along the line of flow. Bank cut erosion is caused by water activity cutting into a bank (for example, reservoir banks or stream banks), Status Ranking (Class 1-4) All erosion sites identified within the FERC project boundary were ranked on a severity scale of I to 4, based on ranking definitions provided in the Soil Conservation Service Soil Survey Manual (1993). In this erosion scale, Class 4 is considered the most severe and Class I is least severe. Class I consists of soils that have lost on average less than 25 percent of upper soil horizons, and Class 2 erosion consists of soils that have lost between 25 and 75 percent of the upper soil horizons on average, Soils that have lost 75 percent or more of the upper soil horizons are considered Class 3, and soils that have lost all of the upper soil horizons are considered Class 4. Due to the nature of expected erosion (bank cut), it was anticipated that most of the erosion present at the Williams Fork Project would be Class 4, Resource Risk Description The resource risk associated with each erosion site, at the time of this survey, was assessed and documented. All erosion, based on the nature of its action, presents at least some risk to natural resources occurring in the vicinity, For example, as even small amounts of sediment are carried away from a site, it may have a commensurately small effect on upland areas or downstream aquatic habitat. For the purpose of this survey, resource risks are characterized by significance for each erosion site. For example, those erosion sites that encroach on campgrounds, roads, bridges, or affect wi]dlife or critical habitat downstream are considered significant rcsource risks, Erosion sites that pose resource risks in the form of minor upland loss and/or loss of aesthctic appeal are considered minor resource risks, Erosion sites rcsulting in nothing more than minor loss of upland areas at a very slow, natural rate are ] Soil Survey Division StalT. 1993. Soil Survey Manual. Soil Conservation Service. U.S. Department of Agriculture Han~book 18. williams Fork Reservoir Hydroelectric Project January 2004 Steigers CorporatIOn ErosIOn Survey Report Page 3