Senior Honors Projects, 2010-current

Preferred Name - First Author

Thady, Erin

Date of Award

Spring 2016

Document Type

Dissertation/Thesis

Degree Name

Bachelor of Science (BS)

Department

Department of Biology

Advisor(s)

Dr. Bruce Wiggins

Dr. Christine May

Dr. Idelle Cooper

Abstract

The Shenandoah Valley encompasses some of the highest agricultural producing regions in Virginia, many of which are large contributors of nutrients and sediment. The Conservation Reserve Enhancement Program (CREP) assists landowners in the installation of riparian restoration projects in which cattle are fenced out or a riparian buffer is planted. We examined the temporal effects of riparian restoration and the impact of upstream landuse on water quality for eleven farms participating in the CREP program for various times (from 1 to 14 years). We hypothesized that the length of time that the CREP program has been established would have a positive effect on the water quality of a stream. Water quality was quantified by measuring benthic macroinvertebrate assemblages using the Hilsenhoff Biotic Index (HBI), Virginia Stream Condition Index (VA-SCI), Shannon Diversity Index, and total abundance. GIS analysis was also employed to calculate upstream land use and stream channel characteristics: land use, canopy cover, slope, impervious surface, relief, road density, and watershed area were assessed for the watersheds and 100-meter stream buffers at each sampling site. Single variable and multiple linear regressions were performed separately within the watershed and buffer zones. While no single variable showed a significant relationship, the time since restoration and the percentage of upstream forested land use predicted HBI values, both in the watershed (p = 0.003, R2 = 0.712) and in the buffer zone (p < 0.002, R2 = 0.748). VA-SCI was predicted by time since restoration and upstream impervious surface in the buffer zone only (p = 0.001, R2 = 0.777). These data show that CREP efforts are having a positive effect on water quality, although upstream land use is also an important factor.

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