Date of Project

4-29-2017

Document Type

Honors Thesis

School Name

College of Arts and Sciences

Department

Environmental Science

Major Advisor

Dr. Martha Carlson Mazur

Second Advisor

Dr. Jay Gatrell

Third Advisor

Dr. Roberta Challener

Abstract

Riparian vegetation along streams has many positive effects on water quality and macroinvertebrate communities, especially in agricultural areas. Some of these effects include erosion prevention, pollutant removal, and lower summer water temperatures. There has been much research done examining the link between these riparian areas and streams; however, riparian vegetation is understudied in karst areas. Karst is a geologic formation that is composed of limestone, which dissolves in groundwater, forming sinkholes. Thus, the question this paper seeks to investigate is does riparian vegetation around sinkholes in a karst plain influence water quality within a watershed? Water quality, land cover, and topography were analyzed, in the Blue River watershed in Southern Indiana. Water quality variables analyzed as dependent variables were nitrate concentration and the ratio of pollution intolerant macroinvertebrates to pollution tolerant macroinvertebrates (EPT:C). Land cover variables included percentage of forest and agricultural land cover within the watershed. Geospatial data were collected using ArcGIS and included sinkhole density, total number of sinkholes, number and percentage of non-vegetated and vegetated sinkholes, and the average riparian buffer width. Multiple linear regression analyses showed that more riparian vegetation around sinkholes led to lower nitrate concentrations in the stream when watershed area was taken into account. Analyses also showed that higher nitrate concentrations led to higher EPT:C. Agricultural land cover in the upper watershed was shown to have negative impacts on EPT:C. These findings are useful in determining whether riparian vegetation should be maintained in agricultural areas if water quality is to be maintained.

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