Trog Sink and its Hydrologic Effects on Head Waters of the East Blackburn Fork River

Abstract

A hydrologic model was developed to predict runoff in an urban watershed in Cookeville, TN. In the research area there resides a massive sinkhole responsible for storing and transmitting storm water to the East Blackburn Fork River. The sinkhole is hypothesized to store excess rain water, and release it at a steady rate. Maintaining a higher baseflow discharge well after storms have passed over the watershed. A rain gauge and two stream gauges were deployed to record water level in the sinkhole and at a spring known to be its outlet. ArcGIS Pro software was used to calculate the watershed area and interpret the terrain of the watershed. The hydrologic model HEC-HMS (Army Corps of Engineers) was used to model runoff from a rain event that happened on December 5, 2020. Results showed a normal hydrograph with peak rainfall and a fairly quick return to baseflow estimated at hours compared to the time recorded in field data. Field data showed Trog sink retaining a large volume of water about 8.5ft in height at its maximum, and not allowing the spring to return to base flow for roughly thirteen days. Further research and modeling are hypothesized to display Trog sinks actual retention pattern in a hydrograph and become more synonymous with the field data during the rain events.