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OKLAHOMA STATE UNIVERSITY Biosystems and Agricultural Engineering. Electrical Resistivity Profiling and Hydraulic Properties of Preferential Flow Paths in Alluvial Floodplains. R.B. Miller, D.M. Heeren, G.A. Fox, T. Halihan, D.E. Storm and A.R. Mittelstet.
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OKLAHOMA STATE UNIVERSITY Biosystems and Agricultural Engineering Electrical Resistivity Profiling and Hydraulic Properties of Preferential Flow Paths in Alluvial Floodplains R.B. Miller, D.M. Heeren, G.A. Fox, T. Halihan, D.E. Storm and A.R. Mittelstet ASCE EWRI Conference, May 18, 2010
Introduction • Preferential Flow Paths (PFPs) • Subsurface transport (e.g. phosphorus) • Bypass buffer strips • Transient storage zone PFP
PFP Previous Research • Tracer tests • Rapid flow • Discrete direction • Little P sorption
Preferential Flow: Stream/Aquifer Interaction OKLAHOMA STATE UNIVERSITY Biosystems and Agricultural Engineering Department Ozark Ecoregion
Alluvial floodplains Topsoil: high infiltration rates Subsoil: coarse chert gravel Preferential Flow: Stream/Aquifer Interaction OKLAHOMA STATE UNIVERSITY Biosystems and Agricultural Engineering Department Field Sites Honey Creek gravel bar Barren Fork streambank: topsoil /gravel Alluvial subsoil material obtained from site
Geomorphically Active Preferential Flow: Stream/Aquifer Interaction OKLAHOMA STATE UNIVERSITY Biosystems and Agricultural Engineering Department
ERI Instruments Preferential Flow: Stream/Aquifer Interaction OKLAHOMA STATE UNIVERSITY Biosystems and Agricultural Engineering Department • Geometrics OhmMapper • Lower precision • Large areas • AGI SuperSting • High precision • Small areas
Large Scale Mapping Preferential Flow: Stream/Aquifer Interaction OKLAHOMA STATE UNIVERSITY Biosystems and Agricultural Engineering Department • Abandoned channels and buried gravel bars
High Precision Mapping Honey Creek Flint Creek
ERI Hydraulic Conductivity? • Darcy’s Law: • K function of: • Porosity • Saturation • Pore size • Clay content • Ohm’s Law: • ρ function of: • Porosity • Saturation • Solute concentration • Clay content
Borehole Permeameter
USBR Solution Zone 1: Unsaturated Zone 2: Unsaturated, near WT
ERI Interpolation • Horizontal slices • Variogram • 3-D Ks data
Conclusions • Heterogeneity at each site • Non-random • Connected high K zones: PFPs • Linear ρ-Ks correlation (R2=0.73) • Max Ks increased with stream order • Data for numerical groundwater models
Acknowledge:Oklahoma Conservation Commission (EPA 319 grant)E-mail: derek.heeren@okstate.eduResearch Website: http://biosystems.okstate.edu/Home/gareyf/AlluvialPTransport.htm