PREDICTING AREAS OF SHORELINE EROSION IN SALT FORK LAKE, SOUTHEASTERN OHIO, USING DIGITIAL ELEVATION MODELS (DEMs) AND WINDNINJA

Shoreline erosion along man-made lakes can be influenced by several different factors including: inherited hydrological factors, river valley morphology, long- and short-term weather patterns, and human activities. We modeled the affect of river valley morphology and long-term weather patterns on the development of shoreline erosion in Salt Fork Lake. Salt Fork Lake, which is located about 10 miles northeast of Cambridge OH, was originally intended to be a water source for the city but has become a major recreation area. The area is part of the unglaciated Allegheny Plateau and has, in general, flattened ridgetops and narrow stream valleys. The local geology which consists of the Pennsylvanian-age Conemaugh and Allegheny Groups influences the shape of the lake which is usually less than 1,200-feet wide. An earthen dam was completed in 1967 creating a 2952 acre lake with approximately 65 miles of shoreline.

Areas surrounding the lake with a slope of 20 percent or greater were identified from 2.5 foot-grid DEMs. The high slope areas were clipped using ArcGIS geoprocessing tools with a 100 foot buffer of the lake shape. High slope areas account for about 19 percent, or about 12 miles, of the shoreline. These areas might represent banks created by shoreline erosion, sandstone ledges along the lake shore, or constructed features. Wind data from seven regional airports surrounding the Salt Fork Lake area were analyzed to determine regional wind pattern trends. The WindNinja program was used to evaluate the effects of the local topography on wind speed and direction over the lake. WindNinja modeling suggests that only about 4 percent of the lake surface receives high winds. The model used the regional wind vector and average wind speed. This reduces the amount of shoreline that might be impacted by consistent waves to 8 percent or about 5 miles. We plan to survey these areas for shoreline erosion during the spring and summer of 2011.