Impact of dam operations on hyporheic exchange in the riparian zone of a regulated river
Article first published online: 26 MAY 2009
Copyright © 2009 John Wiley & Sons, Ltd.
Special Issue: Hyporheic Hydrology: Interactions at the Groundwater-Surface Water Interface
Volume 23, Issue 15, pages 2129–2137, 15 July 2009
How to Cite
Hucks Sawyer, A., Bayani Cardenas, M., Bomar, A. and Mackey, M. (2009), Impact of dam operations on hyporheic exchange in the riparian zone of a regulated river. Hydrol. Process., 23: 2129–2137. doi: 10.1002/hyp.7324
- Issue published online: 2 JUL 2009
- Article first published online: 26 MAY 2009
- Manuscript Accepted: 10 MAR 2009
- Manuscript Received: 20 OCT 2008
- hyporheic exchange;
- surface water-groundwater interaction;
- regulated rivers
Dam operations commonly cause large, frequent fluctuations in river stage, which persist for long distances downstream. The stage fluctuations force river water into and out of the banks, defining lateral hyporheic exchange paths. To evaluate the penetration distance and rates of dam-induced hyporheic exchange, we monitored water-table elevation, temperature, and specific conductivity along a transect perpendicular to the Colorado River (Austin, Texas, USA), 15 km downstream of the Longhorn dam. Stage fluctuates daily by almost a metre. The daily hyporheic exchange volume per metre of bank is 1·0 m3. Dam-induced hyporheic exchange penetrates several metres into the riparian aquifer, while water-table fluctuations propagate 30 m into the riparian aquifer. Water chemistry and temperature fluctuate near the channel in response to the flow oscillations. In the absence of dam operations, groundwater would flow steadily through the riparian aquifer towards the river, laterally limiting hyporheic exchange and stabilizing temperatures and water chemistry near the channel. Therefore, dam operations fundamentally change the hydrological, thermal, and geochemical dynamics of riparian aquifers and their hyporheic zones. Copyright © 2009 John Wiley & Sons, Ltd.