HR: 0800h
AN: H51H-0860    [Abstracts]
TI: IMPACT OF STORM CHARACTERISTICS AND LAND USE ON NUTRIENT EXPORT IN TWO CENTRAL INDIANA WATERSHEDS, USA
AU: * Vidon, P
EM: pvidon@iupui.edu
AF: Indiana University-Purdue University, Indianapolis, 723 W. Michigan Street, SL118, Indianapolis, IN 46202, United States
AU: Wagner, L E
EM: laewagne@iupui.edu
AF: Indiana University-Purdue University, Indianapolis, 723 W. Michigan Street, SL118, Indianapolis, IN 46202, United States
AU: Gray, M
EM: mark.gray@veoliawaterna.com
AF: Veolia Water Indianapolis, 1220 Waterway Boulevard, Indianapolis, IN 46204, United States
AB: This study investigates nitrate and dissolved organic carbon (DOC) export during three spring storm events in an agricultural watershed and a mixed agricultural/urban land use watershed in till landscape in Central Indiana, USA. The objectives of the study are (1) to determine how land use affects water, nitrate, and DOC delivery (timing, amount) to streams during spring storms, and (2) to determine nitrate and DOC flow pathways to streams during storms. High frequency stream sampling of nutrients and cations, coupled with hydrograph separations using δ18O, was used to identify water flow pathways and event and pre-event water contributions to the streams. Results indicate that nitrate and DOC concentrations display distinct temporal patterns during spring storm events. DOC concentration increased with stormflow, and peaked with discharge and the peak in event water regardless of land use or storm characteristics. Nitrate concentrations followed Ca2+, Mg2+, and Na+ trajectories and decreased with stormflow in both watersheds. In addition, the nitrate concentration peak was delayed relative to DOC in the mixed land use watershed. Data suggest that during storms, DOC is exported either via overland flow or via preferential flow through soil macropores. On the other hand, nitrate appears to be mainly delivered to streams in association with pre-event water via subsurface flow. This study contributes to a better understanding of nutrient export pathways during storms for a variety of land uses and to the development of better management strategies and nutrient loading models at the watershed scale.
DE: 0402 Agricultural systems
DE: 1804 Catchment
DE: 1871 Surface water quality
DE: 1879 Watershed
SC: Hydrology [H]
MN: 2007 Fall Meeting