HR: 10:30h
AN: NB52E-01    [Abstracts]
TI: Influence of Hyporheic Exchange on Solute Transport in a Highly Hydropower-Regulated River
AU: * Worman, A
EM: anders.worman@bt.slu.se
AF: Dept. of Biometry and Engrg / SLU, P.O. Box 70 32, Uppsala, S-750 07 Sweden
AU: Jonsson, k
EM: karin-j@kemakta.se
AF: Kemakta Konsult AB, P.O. Box 12 655, Stockholm, S-112 93 Sweden
AB: This study is a first step to understand the effect of hyporheic exchange on solute transport in larger rivers and to investigate whether river regulation alters the hyporheic zone interaction. The present study focuses on the effect of hyporheic exchange on inert solute transport in the Lule River, northern Sweden. A modelling framework comprising both a hydraulic and a solute transport model was developed. Recent theories for the hydrodynamics of the hyporheic exchange were used to generalize exchange relationships developed for a smaller stream system to the Lule River. The effect of hyporheic exchange on solute transport was investigated by means of numerical simulations during both regulated and unregulated conditions. The dissolved hyporheic exchange significantly affected solute transport in both the regulated and the unregulated Lule River. The hyporheic exchange caused significant retardation of an inert solute pulse. In the unregulated river, the expected residence time could be prolonged by ~100 percents compared to the case where no hyporheic exchange was present. This prolongation provides changed reaction times in the river, which can be of importance to possible chemical and biological processes. Further, hyporheic exchange caused the relative spread of an inert solute pulse to increase by up to ~11 times compared to the case where no hyporheic exchange was present. The effect was found to be largest in the unregulated river. The spreading of the pulse implies a smoothing out of temporal variations of the solute concentrations in the Lule River.
DE: 1719 Hydrology
DE: 1890 Wetlands
DE: 4842 Modeling
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly