IDENTIFYING KARST RESOURCES WITHIN A NATIONAL PARK: THE EXAMPLE OF THE CHESAPEAKE AND OHIO CANAL NATIONAL HISTORIC PARK

For the past two years there has been a multidisciplinary effort to understand the extent, impact and origins of the karst resources in the Chesapeake and Ohio Canal National Historic Park (CHOH). These resources contain a variety of subterranean biota, geologic features and cultural artifacts of interest to the National Park Service. Geographically, the CHOH karst is located near the center of the Great Valley province. In this region, the karst is characterized by diffuse-distributary flow, passage development disconnected to present geomorphic processes, and poorly understood recharge sources. For this project 21 CHOH caves were surveyed, 16 springs were inventoried, and 21 waters were sampled. Relevant sections of the canal were checked for previously unknown resources, resulting in the discovery of six new caves and springs and additional passage in two known caves.

All karst resources exist along a 39 km stretch of the canal immediately west of Harpers Ferry, WV. Most caves and springs can be found within two Cambro-Ordovician limestone formations: the Elbrook and Conococheague. Nearly all caves in the park are small (<70m), maze-like and located near the surface. Those qualities, combined with a lack of vadose dissolution features, suggest that most caves were enlarged under slow moving, phreatic conditions. Only one cave, Dam #4, currently has an active stream. Fourteen of the 16 springs inventoried appear to be perennial. Numerous other ephemeral springs were located but not included in this study. Most inventorying took place during baseflow conditions to ensure minimal impact from rainfall. Two of the spring-stream systems deposit observable travertine; a feature not previously identified as a park resource. One of these springs is adjacent to Dellinger Cave but appears to be hydrologically unconnected to the cave and other nearby springs. This spring is directly above a mapped major fault and consequently it may represent the discharge of a particularly deep flowpath system. Based on the distribution of springs, regional karst patterns and geologic structures, the remaining springs are likely to have long, narrow catchments oriented along strike.