| Presentation |
| Paper |
Brian Evans
University of North Carolina at Asheville
Subject Listing - Environmental Studies
Advisor: Dr. Steven C. Patch
Thursday, Oral Session 1, Presentation 2, New Hall 118
THE EFFECT OF AN EXTREME FLOODING EVENT ON LONG-TERM WATER QUALITY IN THE SOUTHERN APPALACHIANS
In September 2004, the remnants of three hurricanes, Frances, Ivan and Jeanne, brought high levels of rainfall and intense flooding to Western North Carolina. The goal of this study was to assess the effects of the hurricanes on the water quality of three subwatersheds of the French Broad River, and determine if there have been any long-term effects. This study also determines how land-use, slope, and rainfall influenced flood severity and impact. Stream samples collected between October 2003 and August 2004 were analyzed and compared with samples collected between October 2004 and August 2005. Water samples were tested for pH, alkalinity, turbidity, total suspended solids, heavy metals, and nutrient content. Post-hurricane benthic monitoring was done at sites with pre-hurricane data using the standard NC Division of Water Quality (DWQ) "EPT" collection method, where only the most pollutant-intolerant groups are collected, mayflies, stoneflies and caddis flies. These data were compared with past data obtained from DWQ. Areas of stream bank erosion were located by aerial photography, personal interviews with local officials associated with the monitoring of each subwatershed, and GIS-based modeling of stream channel morphological characteristics using the HEC-GeoRAS model. USGS Stream flow data, along with precipitation data supplied by the National Weather Service, was used to estimate the flood intensity for each subwatershed. Land Cover data were separated into three categories: agricultural, urban and forested. Mixed linear models were used to assess differences in water quality pre- and post-flooding and the effects of land-cover on the degree of variation. Using overlay analysis in ArcGIS, the results of each of the water quality tests were compared with land-cover classification in order to estimate the effects of land cover on response to the hurricanes.
Advisor: Dr. Steven C. Patch, Professor, Department of Mathematics, University of North Carolina at Asheville, Asheville, NC