Identifying the Stream Erosion Potential of Cave Levels in Carter Cave State Resort Park, Kentucky, USA

摘要

Cave levels, passages found at similar elevations and formed during the same constant stream base level event, reveal information about paleoclimates and karst geomorphology. The investigation presented here examines how Stream Power Index (SPI) relates to cave levels. The study area, Carter Caves State Resort Park (CCSRP), is a fluviokarst system in northeastern Kentucky containing multiple cave levels. SPI determines the erosive power overland flow based on the assumption that flow accumulation and slope are proportional to potential for sediment entrainment. Part of this digital terrain analysis requires the creation of a flow accumulation raster from a digital elevation model (DEM). In creating the flow accumulation raster, one has the option to fill depressions (also considered errors) within the DEM. Filling these depressions, or “sinks,” creates a well-connected stream network; however it also removes possible sinkholes from the DEM. This paper also investigates the effects a filled and an unfilled DEM have on SPI and what each reveals about erosion potential in the area. The data shows that low elevations within the filled DEM maintain a high SPI value when compared to the unfilled DEM. The filled DEM also created a stream network similar to reality. The unfilled DEM demonstrated similar SPI results between all levels, indicating a well-connected karst system. In order to truly understand the mechanics of this system, a combination of these two DEMs is required.