
Wednesday, December 5, 2007 : 11:00 a.m.
Channel Bar Hydrogeology: Ideas for Ground Water and Surface Water Exchange
Ground water mounds and a water table depression, relative to the adjacent river stage, are evident and the spatial area and relative height differences are consistent over time. Variability in river stage and precipitation events did not significantly alter the potentiometric surface features, reducing the importance of infiltration recharge alone. An application of the numerical code TOUGH2 was developed to simulate saturated and unsaturated flow patterns and heat transport within the channel bar. Additionally, a multi-component analysis was completed that synthesized flow patterns, water quality, geochemical analysis, microbial analysis, and heat tracing in an effort to determine the physical mechanisms for ground water mounding.
We present several possibilities for processes that may induce the water table features and suggest that non-Darcian flow patterns may be responsible. These potentiometric surface features may have a significant impact on nutrient dynamics within the subsurface. These effects are realized when the localized variances in water quality and chemistry occur with flux into the surface water.
Christopher L. Shope, Desert Research Institute Christopher L Shope is a graduate student in hydrogeology at the University of Nevada in Reno. His research focuses on ground water and surface water interactions using heat as a tracer. Chris earned his BS in hydrogeology from Western Michigan University, his MS in Hydrogeological Engineering from Montana Tech and is currently a pursuing his PhD in Hydrologic Sciences.
W. Alan McKay, Desert Research Institute Alan W. McKay has over 20 years of experience in a broad range of hydrologic studies. His research has included; surface geophysics applications, hydrogeochemical investigations, and non-point source pollution from agriculture and mining activities. Alan is an Associate Research Hydrologist with the Desert Research Institute in Reno, Nevada.