STREAM CONDUCTIVITY IN JOHN BOYD THACHER STATE PARK

Conductivity is a useful tool to describe water quality and the amount of total dissolved solids a water source contains. By taking this measurement you can infer where the source originates. The electrical conductivity of the two underground streams that flow over the John Boyd Thacher State Park’s Indian ladder trail is not monitored via stream gaging or EPA testing. Due to the karst topographic nature of the limestone’s that make up the Helderberg Escarpment in upstate New York, there are sinkholes and cracks in the rock formations that feed these streams. This research used a conductivity meter to determine the conductivity of water samples taken at locations at and around these underground streams to determine the source of the water. The measurements were taken before and after a precipitation event at the underground streams, the surface streams, and Thompson’s lake. As evident by the Guide to the Geology of John Boyd Thacher Park, Thompson’s lake drains into the same formations as the streams on the Indian ladder trail. The precipitation and stream gaging information from the USGS and the NADP was used to interpret the measurements taken, and each water input was correlated to the surface runoff using a simple 2S test. While the closest sinkhole-sump formation was only trickling drops of water, the underground streams were flowing at a much higher volume, this observation also supports the hypothesis. Coupled with the measurements taken, this information was used to conclude that the underground streams are most likely not fed by one source of water. Further research could evaluate how the water quality changes as runoff feeds the karst streams that flow underneath the park, along with where the specific pathways lie in the topography.