13 Karst Hydrogeology

Thursday, 19 March 2015
1:30 PM - 5:30 PM
Case Study 2

KARST INVENTORY MAPPING IN NORTHERN ARKANSAS

Paper number: 13-10
Program: Theme Sessions
Time: 4:15 PM – 4:35 PM

Authors

Abstract

In the Ozark Plateaus of Arkansas, karst aquifers are an important drinking water source. Several studies indicate that karst features, such as sinkholes and caves, increase susceptibility of groundwater and surface water to contamination. Contaminants sourced from various land-use activities are readily introduced into the groundwater in karst areas due to the predominance of focused, conduit flow. The Buffalo River was analyzed in a previous study that showed for similar agricultural land-use areas, groundwater in areas with a high density of karst features tended to have higher nitrate concentrations. However, relatively few studies have quantified the relation between the quantity of karst features (an indication or metric for degree of karst development) and water quality. Here we show that digitizing topographic maps of northern Arkansas currently has resulted in the identification of 274 springs, 566 sinkholes, and 16 caves mapped within Benton, Washington, and Carroll counties, alone.

ArcGIS will be used to digitize karst features from existing databases and topographic and geologic maps for the Ozarks. Features included will be natural and anthropogenic. Natural attributes will include springs, caves, sinkholes, lineaments, faults, geologic units, and gaining/losing stream segments. Anthropogenic features will include quarries and mines which will be analyzed by using isotope data to determine if they are a source of contamination in karst groundwater systems. The objective of the study is to produce an interactive map for public use of karst features as a metric of karst development that will provide a better understanding of the relative vulnerability of groundwater to contaminants, allowing improved protection of drinking water sources. The density of occurrence of karst features will be combined with water-quality data to assess relative susceptibility of groundwater to contamination. Many water-quality issues in northern Arkansas may be addressed by the completion of the karst inventory map.