Final phase 1 report with emphasis on Fitton Cave area : Inventory and delineation of karst hydrology features, Buffalo National River, Arkansas

Aley, Thomas; Aley, Catherine

This report deals with the first phase of a two phase study to inventory karst hydrology features and to delineate groundwater recharge areas for important features and areas. Two study areas were involved in these investigations. The Regional Study Area is the larger area, and includes within it the Fitton Cave Study Area. During the Phase 1 work all groundwater tracing was limited to locations within the Fitton Cave Study Area. During the Phase 2 work the groundwater tracing work focused on the Regional Study Area. A subsequent report will deal with the findings from the Phase 2 work. Section 1 of this report summarizes previous work in the regional study area with special attention to the Fitton Cave Study Area. Several previous groundwater traces (including two by the National Park Service) provided both credible and valuable data. Section 2 of this report involved mapping of karst features in the Regional Study Area and identification of areas where land use activities might present hazards to groundwater quality. One of the important conclusions from this work was that essentially all of the streams in the areas underlain by the Boone Formation are losing streams, even when the streams have perennial flow. Losing streams are very important groundwater recharge areas. Land uses which can adversely impact groundwater quality can be divided into point sources and non-point sources. While there are some point source groundwater quality hazard areas which we located and assessed, most of the land uses which impact or could impact groundwater quality are non-point sources. Section 3 of the report dealt with groundwater tracing investigations to delineate the recharge area for Fitton Spring (which is analogous to the recharge area for Fitton Cave). A total of 13 sampling stations were established for this groundwater tracing work, and 1 1 separate dye introductions were made during the study. There were five successful traces to Fitton Spring (two of these also yielded dye to Van Dyke Spring). There were six successful groundwater traces to Van Dyke Spring, and two groundwater traces which yielded dye to neither Van Dyke Spring nor Fitton Spring. The delineated recharge area for Fitton Spring is shown in Figure 3 and consists of two areas. The total area which contributes recharge water to Fitton Spring is 5.40 square miles (3,460 acres). Approximately 92% of this area also contributes recharge water to Van Dyke Spring. The total area which contributes recharge water to Van Dyke Spring is also shown on Figure 3 and encompasses 12.59 square miles (8,050 acres). To avoid misunderstandings, the areas which share recharge waters with Fitton and Van Dyke Springs do so in the following manner. During storm events some runoff water sinks from the surface into the groundwater system which feeds Fitton Spring. However, especially during larger runoff events, not all of the runoff water sinks; some remains on the surface until it has left the area which contributes water to Fitton Spring and then some of this surface runoff water enters the groundwater system where it contributes to the flow of Van Dyke Spring. We found no evidence in this study of any areas where the associated groundwater discharges from both of these springs. It is our conclusion that the most significant present adverse hydrologic impact on Fitton Cave and Fitton Spring is probably sediments derived from the steep NPS service road which leads from the Erbie Road to the old cabin near Chestnut Spring. This road provides valuable access to the cave so that NPS personnel can routinely change the lock combination and check for forced entry into the cave. If this road is to remain open actions are needed to reduce erosion of the road and sediment input into the karst groundwater system.