Toward a conceptual model relating chemical reaction fronts to water flow paths in hills

a Earth and Environmental Systems Institute, Pennsylvania State University, University Park, PA 16802, USA b Department of Geosciences, Pennsylvania State University, University Park, PA 16802, USA c Department of Geology and Geological Engineering and Hydrologic Science and Engineering Program, Colorado School of Mines, Golden, CO 80401, USA d Department of Geography and Atmospheric Sciences, University of Kansas, Lawrence, KS 66045, USA e Department of Geosciences and Watershed Studies Institute, Murray State University, Murray, KY 40271, USA