Hydrologic Modeling of Flow through Sinkholes Located in Streambeds of Cane Run Stream, Kentucky

Abstract

Hydrologic modeling of karst watersheds requires detailed information on geologic settings and hydrologic properties for efficient simulation of spring and streamflow hydrographs. In this paper, sinkholes located in the streambed of a karst watershed in Kentucky were conceptualized as orifices, and flow through these orifices was modeled as a function of sinkhole diameter. The karst flow components were incorporated in a soil and water assessment tool (SWAT), called KarstSWAT in this study. The KarstSWAT was able to reproduce the observed hydrographs better than the SWAT model in terms of both peak flow and hydrograph volume. Flow through a groundwater basin that is partly fed by the sinkholes and is discharged from a spring was estimated using a method called the successive summation routing algorithm (SSRA) in this study. The time series analysis of simulated spring flows showed that the quantity of water recharging the sinkholes was sufficient to reproduce the observed spring hydrographs. The proposed method could be adapted to karst watersheds dominated by sinkholes and to watersheds that drain water from sinkholes to springs.