Imaging rainfall drainage within the Miami oolitic limestone using high‐resolution time‐lapse ground‐penetrating radar

[1] The vadose zone of the Miami limestone is capable of draining several centimeters of rainfall within a fraction of an hour. Once the water enters the ground, little is known about the flow paths in the oolitic rock. A new rotary laser-positioned ground-penetrating radar (GPR) system enables centimeter-precise and rapid acquisition of time-lapse surveys in the field. Two-dimensional (2-D) GPR time-lapse surveying at a 3-min interval before, during, and after rainfall shows how buried sand-filled dissolution sinks efficiently drain the bulk of the rainwater. Hourly repeated 3-D imaging of a dissolution sink in response to surface infiltration shows how the wetting front propagates at a rate of 0.6–1.2 m/h traversing the 5-m-thick vadose zone within hours. At the same time, some of the water migrates laterally into the host rock guided by stratigraphic unit boundaries. Average lateral propagation measured over a 28-hour period was of the order of 0.1 m/h. On a seasonal time frame, redistribution involves the entire rock volume. Comparing 3-D surveys acquired after wet summer and dry winter conditions shows good GPR event correspondence, but also time shifts up to 20 ns caused by the change of overall water content within the vadose zone. High-precision time-lapse GPR imaging can therefore be used to noninvasively characterize natural drainage inside the vadose zone ranging from transient loading to seasonal variation.

[1]  M. Toksöz,et al.  Velocity variations and water content estimated from multi-offset, ground-penetrating radar , 1996 .

[2]  Remke L. Van Dam,et al.  Identifying causes of ground‐penetrating radar reflections using time‐domain reflectometry and sedimentological analyses , 2000 .

[3]  M. Vanclooster,et al.  Effect of soil roughness on the inversion of off‐ground monostatic GPR signal for noninvasive quantification of soil properties , 2006 .

[4]  Ralf J. Weger,et al.  Full-resolution 3D GPR imaging , 2005 .

[5]  Immo Trinks,et al.  Monitoring water flow in the unsaturated zone using georadar , 2001 .

[6]  David Lumley,et al.  Cross‐equalization data processing for time‐lapse seismic reservoir monitoring: A case study from the Gulf of Mexico , 2001 .

[7]  J. Best,et al.  Three-Dimensional Sedimentary Architecture of a Large, Mid-Channel Sand Braid Bar, Jamuna River, Bangladesh , 2003 .

[8]  Vincent C. Tidwell,et al.  Laboratory method for investigating permeability upscaling , 1997 .

[9]  Thomas Aigner,et al.  Towards realistic aquifer models: Three-dimensional georadar surveys of Quaternary gravel deltas (Si , 1999 .

[10]  S. Truss.  Characterisation of sedimentary structure and hydraulic behaviour within the unsaturated zone of the Triassic Sherwood Sandstone aquifer in North East England , 2004 .

[11]  Andrew Binley,et al.  High‐resolution characterization of vadose zone dynamics using cross‐borehole radar , 2001 .

[12]  U. Asprion,et al.  Aquifer architecture analysis using ground-penetrating radar: Triassic and Quaternary examples (S. Germany) , 1997 .

[13]  G. McMechan,et al.  Detailed internal architecture of a fluvial channel sandstone determined from outcrop, cores, and 3-D ground-penetrating radar: Example from the middle Cretaceous Ferron Sandstone, east-central Utah , 2001 .

[14]  Erwan Gloaguen,et al.  Estimation of hydraulic conductivity of an unconfined aquifer using cokriging of GPR and hydrostratigraphic data , 2001 .

[15]  T. Aigner,et al.  Three-dimensional GPR analysis of various Quaternary gravel-bed braided river deposits (southwestern Germany) , 2003, Geological Society, London, Special Publications.

[16]  Johan Alexander Huisman,et al.  Measuring soil water content with ground penetrating radar , 2003 .

[17]  D.C. Nobes,et al.  Radar "lensing" by a small river: can a layer of surface water improve the signal? , 2004, Proceedings of the Tenth International Conference on Grounds Penetrating Radar, 2004. GPR 2004..

[18]  Susan S. Hubbard,et al.  Mapping the volumetric soil water content of a California vineyard using high-frequency GPR ground wave data , 2002 .

[19]  Susan S. Hubbard,et al.  Field‐scale estimation of volumetric water content using ground‐penetrating radar ground wave techniques , 2003 .

[20]  S. Siegesmund,et al.  Correlation between rock fabrics and physical properties of carbonate reservoir rocks , 1999 .

[21]  A. P. Annan,et al.  Ground-penetrating radar for high-resolution mapping of soil and rock stratigraphy , 1989 .

[22]  D. Daniels.  Ground Penetrating Radar , 2005 .

[23]  Alan G. Green,et al.  Using two- and three-dimensional georadar methods to characterize glaciofluvial architecture , 1999 .

[24]  R. Weger,et al.  Three-dimensional ground-penetrating radar imaging of sedimentary structures, fractures, and archaeological features at submeter resolution , 2004 .

[25]  Rodney Calvert,et al.  4D technology: where are we, and where are we going? , 2005 .

[26]  Anthony L. Endres,et al.  Ground Penetrating Radar Imaging of an Aquifer During a Pumping Test , 2000 .

[27]  H. Jol,et al.  Ground-penetrating radar investigation of a Lake Bonneville deita, Provo level, Brigham City, Utah , 1992 .

[28]  A. Neal.  Ground-penetrating radar and its use in sedimentology: principles, problems and progress , 2004 .

[29]  Mark Grasmueck,et al.  Integration of Ground-Penetrating Radar and Laser Position Sensors for Real-Time 3-D Data Fusion , 2007, IEEE Transactions on Geoscience and Remote Sensing.

[30]  A. P. Annan,et al.  Electromagnetic determination of soil water content: Measurements in coaxial transmission lines , 1980 .

[31]  R. A. Overmeeren,et al.  Ground penetrating radar for determining volumetric soil water content ; results of comparative measurements at two test sites , 1997 .

[32]  Anthony L. Endres,et al.  The non-invasive characterization of pumping-induced dewatering using ground penetrating radar , 2003 .

[33]  A. P. Annan,et al.  Measuring Soil Water Content with Ground Penetrating Radar: A Review , 2003 .

[34]  Georgios P. Tsoflias,et al.  Monitoring pumping test response in a fractured aquifer using ground‐penetrating radar , 2001 .

[35]  A. Peter Annan,et al.  Ground‐penetrating radar monitoring of a controlled DNAPL release: 200 MHz radar , 1994 .

[36]  A. Binley,et al.  Vadose zone flow model parameterisation using cross-borehole radar and resistivity imaging , 2001 .

[37]  K. Cunningham.  Application of ground-penetrating radar, digital optical borehole images, and cores for characterization of porosity hydraulic conductivity and paleokarst in the Biscayne aquifer, southeastern Florida, USA , 2004 .

[38]  J. E Hoffmeister,et al.  Miami Limestone of Florida and Its Recent Bahamian Counterpart , 1967 .

[39]  J. H. Hudson,et al.  Pleistocene Barrier Bar Seaward of Ooid Shoal Complex Near Miami, Florida , 1977 .

[40]  Ralf Birken,et al.  Use of four-dimensional ground penetrating radar and advanced visualization methods to determine subsurface fluid migration , 2000 .