An understanding of groundwater/surface water interaction is a critical component of watershed analysis, but locating groundwater exchange zones is challenging when seepage occurs underwater in streambed or lakebed sediments. We have been studying geophysical methods – specifically electrical resistivity and ground penetrating radar –to supplement traditional point measurements made using seepage meters. Our lake study site was Mirror Lake, New Hampshire in the Hubbard Brook Experimental Forest. Our stream study sites are urban streams in Pennsylvania. One of the streams, Crabby Creek, has been the site of a stream restoration project
FUNDING: This project was funded through a previous grant from the National Science Foundation (NSF) hydrologic Sciences program.
Collaborators include Jonathan Nyquist from my department at Temple (geophysicist), Rob Ryan of Temple Engineering and Don Rosenberry of the USGS.
Toran, L. Groundwater-surface water interactions. In. Maurice, P. ed. Encyclopedia of Encyclopedia of Water: Science, Technology, and Society. John Wiley and Sons. pdf
Toran, L., Nyquist, J., Rosenberry, D., Gagliano, M., Mitchell, N., & Mikochik, J., 2015. Geophysical and Hydrologic Studies of Lake Seepage Variability. Groundwater. 53(6): 841-850. DOI: 10.1111/gwat.12309
Toran, L., Hughes, B., Nyquist, J., and Ryan, R., 2013. Freeze Core Sampling to Validate Time‐Lapse Resistivity Monitoring of the Hyporheic Zone. Ground Water, 51: 635-640.
Toran, L, Hughes, B., Nyquist, J.E. Ryan, R. 2012. Using hydrogeophysics to monitor change in hyporheic flow around stream restoration structures. Environmental & Engineering Geoscience, 18, 83-97.
Toran, L., Nyquist, J.E., Fang, A. C., Ryan, R.J., and Rosenberry, D.O. 2012. Observing heterogeneity in hyporheic flow with electrical resistivity and subsurface well sampling during a stream tracer test. Hydrologic Processes, DOI: 10.1002/hyp.9269.
Rosenberry, D.O., Toran, L., and Nyquist, J.E. 2010. The effect of surficial disturbance on exchange between groundwater and surface water in near-shore margins. Water Resources Research, 46, W06518, doi:10.1029/2009WR008755.
Toran, L, Johnson, M., Nyquist, J., and Rosenberry, D. 2010. Delineating a road salt plume in lakebed sediments using electrical resistivity, piezometers, and seepage meters at Mirror Lake, NH. Geophysics, 75 (4), 73-85.
Nyquist, J., Heaney, M. and Toran, L, 2009. Characterizing Lakebed Seepage and Geologic Heterogeneity Using Resistivity Imaging and Temperature Measurements. Near Surface Geophysics. 7 (5-6): 487-498.
Nyquist, J. E., Freyer, P. A., and Toran, L. , 2008 Stream Bottom Resistivity Tomography to Map Ground-Water Discharge. Ground Water, 46 (4), 561-569.