Hi, I’m Xun-Hong Chen, professor of hydrogeology in the UNL School of Natural Resources. I work in the fields of groundwater modeling, hydrogeology, stream-aquifer systems, and aquifer tests. I teach Groundwater Modeling and Geostatistics.
As my fields of interest indicate, a good deal of my work involves the analysis of groundwater systems. Water is one of the world’s most valuable and vulnerable resources, which makes the study of water increasingly important.
To better understand how water flows, my research often employs computer models. Some of these models explore how groundwater irrigation affects stream depletion. In other projects, I integrate multiple models like ground- and surface-water models to more fully illustrate the water processes involved. I use public-domain modeling software. I also develop my own computer source codes using the Galerkin finite-element method; they have been used to simulate air flow around a soil-vapor extraction well (Fig. 1), stream-aquifer interactions (Fig. 2), biodegradable contaminant transport in heterogeneous porous media (Fig. 3) and radial groundwater flow to pumping wells.
In addition to modeling, my research also studies the hydraulic properties of aquifers and stream-bed sediments. Many times, this work will take the information gathered about hydraulic properties and examine the role these properties have in stream flow depletion.
Currently, I am using some of the modeling techniques described above to explore the hydrologic cycle in the Nebraska Sandhills, in the Platte and Republican River valleys, as well as in the Blue River basin and the Elkhorn River basin, Nebraska. I have determined some of the aquifer’s hydraulic properties and then studied their role in the interaction of groundwater and stream water.
I have been at UNL since 1994. Before my tenure with the School of Natural Resources, I worked with an environmental/hydrogeologic consulting company for three years in Wyoming. I have collaborative research projects with a number of universities in China such as Zhejiang University, Hohai University, Beijing Normal University, Chang’An University, and Northwest University.
Figure 1. Air flow lines from the ground surface to a gas extraction well. Zd and rd are scaled vertical and radial axis, respectively.
Figure 2. Flow net for a vegetation-aquifer-stream profile. The river gains water from the left side and loses water to the right side. The unit for the vertical and horizontal axis is meter.
Figure 3. Simulated contaminant plume in a porous media of heterogeneous hydraulic conductivity. One gird = two meters.
Key Research Publications
Song, J., X. H. Chen, C. Cheng, S. Summerside, and F. Wen, 2007. Effects of hyporheic processes on streambed vertical hydraulic conductivity in three rivers of Nebraska, Geophysical Research Letters, 34, L07409, doi:10.1029/2007GL029254.
Chen, X.H., 2007. Hydrologic connections of a stream-aquifer-vegegation zone in south-central Platte River Valley, Nebraska. Journal of Hydrology 333: 554-568.
Chen, X.H., and L. Shu, 2006. Groundwater evapotranspiration captured by seasonally pumping wells in river valleys. Journal of Hydrology 318: 334-347.
Wen, F. J. and X. H. Chen, 2006. Evaluation of the impact of groundwater irrigation on streamflow depletion in Nebraska. Journal of Hydrology 327: 603-617.
Chen, X, Y. Q. Chen, and X. H. Chen, 2006. Separation of baseflow accounting for the effect of bank storage. Journal of Hydrology 327: 5390549.
Chen, X.H., and Y. Yin, 2006. The Flexible Tolerance Method for estimating the evapotranspiration and infiltration in the root zone. Journal of American Water Resources Association 42(2): 495-512.
Zhang, Y. I. A. Khan, X. H. Chen, and R. F. Spalding, 2006. Transport and persistence of ethanol in groundwater. Journal of Contaminant Hydrology 82: 183-194.
Chen, X.H., and Y. Yin, 2004. Semi-analytical solutions for stream depletion in partially penetrating streams. Ground Water 42 (1), 92-96.
Chen, X.H., and X. Chen. 2004. Simulating the effects of reduced precipitation on groundwater and streamflow in the Nebraska Sand Hills. Journal of the American Water Resource Association 40(2): 419-430.
Chen, X. H., 2004. Streambed hydraulic conductivity for rivers in south-central Nebraska. Journal of the American Water Resource Association 40(3): 561-574.
Chen, X.H., and X. Chen, 2003. Sensitivity analysis and determination of streambed leakance and aquifer hydraulic properties. Journal of Hydrology 284:270-284.
Chen, X., and X. H. Chen, 2003. Stream water infiltration, bank storage, and storage zone changes due to stream-stage fluctuations. Journal of Hydrology, v. 280, p. 246-264.
Chen, X.H., and X. Chen, 2003. Effects of aquifer anisotropy on the migration of infiltrated stream water to a pumping well. Journal of Hydrologic Engineering 8(5), 287-293.
Chen, X. H., J. Goeke, J.F. Ayers, and S. Summerside, 2003. Observation well network design for pumping tests in unconfined aquifers. Journal of American Water Resources Association 39(1), 17-32.
Chen, X.H., and L.C. Shu, 2002. Stream-aquifer interactions: evaluation of depletion volume and residual effects from ground water pumping. Ground Water 40(3), 284-290.
