Department: Geological and Atmospheric Sciences, Environmental Science
Research Interests: physical/chemical hydrogeology, groundwater quality in agricultural watersheds, groundwater/surface water interaction, effects of climate change and biofuels development on groundwater sustainability
Brief description of current research:
Dr. Simpkins' current research is focused in five major areas:
1) the hydrogeology and geochemistry of till and related glacial sediments;
2) the groundwater quality of restored, multi-species riparian buffers in agricultural watersheds;
3) processes controlling nutrient transport via groundwater to lakes and streams in Iowa;
4) application of groundwater modeling to predict the hydrologic effects of conservation practices in agricultural watersheds;
5) assessing the sustainability of alluvial aquifers in central Iowa under changing climate and biofuels development.
Helmers, M.J., T.M. Isenhart, C.L. Kling, T.M. Moorman, W.W. Simpkins, and Mark Tomer. 2007. Water quality in Agriculture 101: Heterogeneity of pollutants, practices, and programs. Choices.
Schilling, K.E., M. Tomer, P.E. Gassman, C.L. Kling, T.M. Isenhart, T.B. Moorman, W.W. Simpkins, C.F. Wolter. 2007. A tale of three watersheds: non-point source pollution and conservation practices across Iowa. Choices.
Simpkins, W.W. 2006. A multi-scale investigation of ground water flow at Clear Lake, Iowa. Ground Water 44 (1):35-46.
Helmke, M.F., W.W. Simpkins, and R. Horton. 2005. Simulating conservative tracers in fractured till
under realistic timescales. Ground Water 43 (6):877-889.
Helmke, M.F., W.W. Simpkins, and R. Horton. 2005. Fracture-controlled transport of nitrate and
atrazine in four Iowa till units. J. Environ. Qual. 34:227-236.
Helmke, M.F., W.W. Simpkins, and R. Horton. 2004. Experimental determination of effective diffusion parameters in fractured till. Vadose Zone Journal 3:1050-1056.
Burkart, M.R., W.W. Simpkins, A.J. Morrow, and J.M. Gannon. 2004. Occurrence of total dissolved phosphorus in surficial aquifers and aquitards in Iowa. J. Amer. Water Resources Assoc. 40(3):827-834.
Schultz, R.C., T.M. Isenhart, W.W. Simpkins, and J.P. Colletti. 2004. Riparian forest buffers in agroecosystems – lessons learned from the Bear Creek Watershed, central Iowa, USA. Agroforestry Systems 61:35-50.