Abstract
Pending
Download.
In Press
Abstract
Pending
Download.
In Press
As featured on the Geology Department’s News page, a team of our researchers were out measuring the flow and water quality of 64 streams that drain 80% of the Lower Peninsula into the Great Lakes.
Abstracts are invited for “NovCare2011″: Novel Methods for Subsurface Characterization and Monitoring – From Theory to Practice” co-organized by the hydrogeology group http://www.novcare.org.
The Hydrogeology Group has been awarded with a $1.2M NSF grant to predict sustainable solutions for communities across the High Plains that rely upon a diminishing water supply. Read more: http://news.msu.edu/story/8467/
Electrical resistivity of soils and sediments is strongly influenced by the presence of interstitial water. Taking advantage of this dependency, electrical-resistivity imaging ERI can be effectively utilized to estimate subsurface soil-moisture distributions. The ability to obtain spatially extensive data combined with time-lapse measurements provides further opportunities to understand links between land use and climate processes. In natural settings, spatial and temporal changes in temperature and porewater salinity influence the relationship between soil moisture and electrical resistivity. Apart from environmental factors, technical, theoretical, and methodological ambiguities may also interfere with accurate estimation of soil moisture from ERI data. We have examined several of these complicating factors using data from a two-year study at a forest-grassland ecotone, a boundary between neighboring but different plant communities. At this site, temperature variability accounts for approximately 20%–45% of resistivity changes from cold winter to warm summer months. Temporal changes in groundwater conductivity mean 650 S/cm; 57.7 and a roughly 100- S/cm spatial difference between the forest and grassland had only a minor influence on the moisture estimates. Significant seasonal fluctuations in temperature and precipitation had negligible influence on the basic measurement errors in data sets. Extracting accurate temporal changes from ERI can be hindered by nonuniqueness of the inversion process and uncertainties related to time-lapse inversion schemes. The accuracy of soil moisture obtained from
ERI depends on all of these factors, in addition to empirical parameters that define the petrophysical soil-moisture/resistivity relationship. Many of the complicating factors and modifying variables to accurately quantify soil moisture changes with ERI can be accounted for using field and theoretical principles.
My research areas are electrical and electromagnetic methods of geophysics and their applications on hydrogeophysics, archaeogeophysics, environmental geophysics. My Ph.D. thesis research focuses on characterization of a highly heterogeneous aquifer using novel characterization methods such as full-resolution 3D GPR and DPP hydraulic conductivity tool. My other research interests are data processing, numerical solutions, modeling, and simulation since I personally like advanced math and coding in Matlab. For more information see my personal website.
My interests include geophysics and hydrogeology with an application to engineering and environmental issues. Current work includes the development of a field data database and an analysis of soil moisture and temperature variability in the shallow subsurface. I will pursue an advanced degree in either hydrogeology or hydrogeophysics in Fall 2011.
B.S. Geological Sciences, Concentration in Geophysics, Michigan State University, May 2011.
SAGE – Summer of Applied Geophysical Experience 2010, Los Alamos, NM.
Study Abroad – Ecology of the Mountains 2010, Lesser Himalayas, India.
bbchrisman@gmail.com
chrisma8@msu.edu
I take an interdisciplinary approach in researching issues related to water quality and quantity. More specifically, I use the principles of landscape ecology together with biogeochemistry and systems modeling to investigate ecosystem services in a changing landscape. My current research evaluates temporal shifts in coupled human and natural systems. To this end, I am using both multivariate statistical techniques and mechanistic models to investigate the role of historical land use/cover in driving physical, chemical, and biological characteristic currently observed in lake, stream, and wetland ecosystems.
Overall, my goal is to conduct research for the purpose of guiding ecosystem management, with ecosystem type unconstrained by salinity or water residence time. One line of research which I plan on pursuing is the concept of land use/cover legacies.
My research interests are in the application and improvement of near-surface geophysical methods for hydrological and engineering problems, sedimentology and stratigraphy, issues of environmental change, and characterization of soils.
Dogan, M., Hyndman, D.W., and Van Dam, R.L., 2009, Geophysical methods to characterize a highly heterogeneous aquifer. Novcare, Leipzig Germany.
Van Dam, R.L., Jayawickreme, D.H., and Hyndman, D.W., 2009, Quantifying vegetation driven moisture dynamics using DC electrical resistivity. AGU Joint Assembly. Toronto, Canada, May 24-27.
Van Dam, R.L., Simmons, C.T., Hyndman, D.W., and Wood, W.W., 2008, Geophysical Characterization of Natural Free Convection in a Coastal Sabkha, Geological Society of America, Annual Meeting, Houston, Texas, October 5-9, 2008. Invited.