SS3.13 Natural Disturbances on Landscapes and Their Impacts on Aquatic Systems
Date: Thursday, June 13, 2002
Time: 4:45:00 PM
Location: Carson A
 
BurkholderJM, North Carolina State University, Raleigh, USA, joann_burkholder@ncsu.edu
Glasgow, H, B, North Carolina State University, Raleigh, USA, howard_glasgow@ncsu.edu
Melia, G, M, North Carolina State University, Raleigh, USA, greg_melia@ncsu.edu
Deamer, N, J, North Carolina State University, Raleigh, USA, nora_deamer@ncsu.edu
 
COMPARATIVE IMPACTS OF HURRICANES ON WATERSHED PROCESSES AND WATER QUALITY IN THE NEUSE RIVER AND ESTUARY
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More hurricanes and tropical storms made landfall in North Carolina from 1996-1999 than in the previous 35 years combined. Impacts of the most severe storms (Hurricane Fran – 1996; and successive hurricanes Dennis, Floyd, and Irene [DFI] - 1999) on the Neuse River and Estuary were evaluated. During H-Fran the watershed received ~14% mean annual precipitation. Dissolved oxygen in freshwater segments was < 2 mg/L for 2 weeks post-Fran, coinciding with high NH4+N, TP, bacteria densities, and with massive fish kills. DO remained > 3 mg/L in most estuarine waters, with no fish kills. Flooding from DFI contributed ~50% of mean annual precipitation. DO was > 5 mg/L post-DI and decreased to 3-5 mg/L for 2 weeks post-Floyd, with no fish kills. Although H-Fran was shorter in duration with less precipitation than H-Floyd, TN and TP loadings to the estuary were much higher from H-Fran (by 20% and 10%, respectively). Thus, hurricanes with high dilution and massive volume of flow can protect receiving waters from extreme oxygen deficits and high pollutant concentrations, relative to those sustained from intensive, low-flooding storms.