The Value of Geophysical Data to the Refinement of a Groundwater-flow Model Les Voigt Fish Hatchery, Bayfield, WI Leah Kammel 1 Peter Chase 2, Carolyn Streiff 2, Michael Baierlipp 3, William Kean 3 1 USGS WIWSC, 2 WGNHS, 3 UW-Milwaukee This information is preliminary and is subject to revision. It is being provided to meet the need for timely best science. The information is provided on the condition that neither the U.S. Geological Survey nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information. WI AWRA March 5, 2015 Photo by Fabiola Buarnè 1
Les Voigt Fish Hatchery WI DNR facility in operation since 1897 Hatching and rearing of brook, brown and lake trout steelhead splake Chinook and coho salmon Increased water needs Hatchery Well 2
Groundwater-flow Model Regional model for the Bayfield Peninsula Cell size of 264 feet Local hatchery scale Feasibility and impact of increasing water supply Refine parameters of regional model using local hydrogeologic data Collect geophysical data to further refine the model at the local scale 3
Geologic Setting Figure adapted from Goebel et al. (1983) and Fitzpatrick et al. (2015)
Geophysical Investigations 1) Borehole logs at existing hatchery well 2) Electrical Resistivity Imaging (ERI) profiles -identify material and structure of subsurface 3) Horizontal-to-vertical spectral ratio (HVSR) passive seismic measurements -estimate depth to bedrock 5
Borehole Logs 800-ft deep water supply well at the hatchery Measured gamma rays, normal resistivity, single point resistivity, fluid conductivity, flow, and temperature Hatchery Well Image log to identify changes in formation and hydrogeologic character 6
Image Log Top of bedrock at 126 Evidence of fractures and intervals of preferential flow near weathered bedrock surface Preliminary Information-Subject to Revision. Not for Citation or Distribution. 7
Electrical Resistivity Imaging (ERI) I: Current injected into ground between two current electrodes V: voltage measured between potential electrodes resulting from the current passing through the subsurface material k: geometric factor determined by electrode configuration Figure from Muchingami, et al. (2013), adapted from Sharma (1997) 8
Electrical resistivity is a function of: -mineral type -porosity -fluid content -dissolved salts, etc. Typical Range of Material Resistivity (ohm-meters) Clays 1-100 Alluvium and sands 10-800 Bedrock 600-6000 (values and figure above from Loke, 2014) 24 electrodes, 5 m spacing Standard survey length of 115 m Measure to depth of 24 m Roll-along surveys of 195 m 9
Location of ERI Profiles Example ERI profiles discussed in next slide 10
Example ERI Profiles LV Fine-grained sediment, silts and clays BR1 Fine-grained sediments Sand and gravel, possibly bedrock Preliminary Information-Subject to Revision. Not for Citation or Distribution. 11
HVSR Measurements Estimate depth to bedrock (thickness of unconsolidated sediment) HVSR = average horizontal spectra (N-S and E-W) vertical spectrum Method first proposed by Nakamura (1989) Peak HVSR value Empirical relationship between resonance frequency and sediment thickness Z=a*f res b (Ibs-von Seht and Wohlenberg, 1999) a = 83 meters b = -1.232 Resonance frequency 37 control locations in fluvio-lacustrine deposits in Minnesota (Chandler and Lively, 2014) Preliminary Information-Subject to Revision. Not for Citation or Distribution. 12
Control point: hatchery well Preliminary Information-Subject to Revision. Not for Citation or Distribution. 13
Refinements to the GW Flow Model AFTER Bedrock surface refined given HVSR estimates BEFORE Very shallow bedrock in regional model layer Inform stratigraphy and model layer structure Future changes to distribution of hydraulic conductivity based on borehole logs and ERI profile results Preliminary Information-Subject to Revision. Not for Citation or Distribution. 14
Takeaways from the Geophysical Investigations Some preferential flow paths near the weathered bedrock surface around 150-175 ft deep Shallow unconsolidated material consists largely of fine-grained sediments (Miller Creek formation) Confirm existence of a bedrock valley that runs under the hatchery between the two streams towards Lake Superior Next steps: alteration of the distribution of hydraulic conductivity based on the ERI profiles and the borehole logs pumping test in the sandstone aquifer 15
Thanks - Funding provided by Wisconsin DNR Bureau of Fisheries Management, USGS Cooperative Water Program - Darren Miller and staff at Les Voigt - Chuck Dunning, USGS WIWSC - Daniel Feinstein, USGS WIWSC 16
References Chandler, V.W., Lively, R.S., 2014, OFR14-01, Evaluation of the horizontal-to-vertical spectral ratio (HVSR) passive seismic method for estimating the thickness of Quaternary deposits in Minnesota and adjacent parts of Wisconsin. Minnesota Geological Survey. Retrieved from the University of Minnesota Digital Conservancy, http://hdl.handle.net/11299/162792. Fitzpatrick, F.A., Peppler, M.C., Saad, D.A., Pratt, D.M., and Lez, B.A., 2015, Geomorphic, flood, and groundwater-flow characteristics of Bayfield Peninsula streams, Wisconsin, and implications for brook-trout habitat: U.S. Geological Survey Scientific Investigations Report 2014-5007, 80 p., http://dx.doi.org/10.3133/sir20145007. Goebel, J.E., Mickelson, D.M., Farrand, W.R., Clayton, L., Knox, J.C., Cahow, A., Hobbs, H.C., and Walton, M.S., Jr., 1983, Quaternary geologic map of the Minneapolis 4 x 6 quadrangle, United States: U.S. Geological Survey Miscellaneous Investigations Series, Map 1-1420(NL-15), scale 1:1,000,000. Ibs-von Seht, M. and Wohlenberg, J., 1999, Microtremor measurements used to map thickness of soft sediments, Bulletin of the Seismological Society of America, v. 89, p. 250-259. Loke, M.H., 2014, Tutorial: 2-D and 3-D Electrical Imaging Surveys, www.geotomosoft.com Muchingami, I., Nel, J., N., Xu, Y., Steyl, G., Reynolds, K., 2013, On the use of electrical resistivity methods in monitoring infiltration of salt fluxes in dry coal ash dumps in Mpumalanga, South Africa. Water SA[online]. 2013, vol.39, n.4. Available from: <http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=s1816-79502013000400006&lng=en&nrm=iso>. ISSN 1816-7950. Nakamura, Y., 1989, A method for dynamic characteristics estimation of subsurface using microtremors on the ground surface, Quarterly Reports of the Railway Technical Research Institute Tokyo, v. 30, p. 25-33. Sharma, P.V., 1997, Environmental Engineering and Geophysics. Cambridge University Press, Cambridge, UK. 17