Tana L. Haluska 201010 raster digital data Reston, VA U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?col_riv_obthk_f Burns, E.R., Morgan, D.S., Peavler, R.S., and Kahle, S.C. 201010 U.S. Geological Survey Scientific Investigations Report 2010-5246 Reston, VA U.S. Geological Survey http://pubs.usgs.gov/sir/2010/5246/ The obthk_f grid represents the modeled thickness of the Overburden geomodel unit at a 500 foot resolution. It is one grid of a geomodel that consists of eleven grids and a spatial extent polygon shapefile. As part of a U.S. Geological Survey Groundwater Resources Program study, a three-dimensional geomodel was constructed for approximately 53,000 mi2 of the Columbia Plateau in Washington, Oregon, and Idaho. This geomodel was constructed to define the general aquifer system geometry for use in a regional numerical groundwater flow model. Simplifications and assumptions consistent with this ultimate goal and the uncertainty in the available data were made. The geomodel units consist of Miocene age Columbia River Basalt Group strata and younger alluvial overburden covering approximately 44,000 mi2. Data were compiled from numerous databases and detailed studies completed during the past three decades. These data include stratigraphic interpretations made on more than 13,000 wells and a contiguous compilation of surficial geology and structural features spanning the study area. These data were simplified and used to construct piecewise-smooth trend surfaces that represent upper and lower subsurface geomodel unit boundaries in this complex folded and faulted terrain. The smoothness of the surfaces implicitly represents uncertainty in prediction of each surface resulting from data gaps, errors in borehole interpretations, errors in mapped contact locations, and uncertainty in the shape of the paleo-surface upon which flood basalts were emplaced. Using a rule-based algorithm, surfaces were then recombined to construct a fully three-dimensional model with a 500-foot grid resolution that is consistent with the data and for which error estimates may be made. The modeling process yielded improved estimates of unit volumes, refinement of location of large structural features, and identification of features that may be important for ongoing groundwater studies. The obthk_f grid represents the modeled thickness of the Overburden geomodel unit and was generated as part of a geomodel that will be used as the foundation for a groundwater flow model for the Columbia Plateau Regional Aquifer System. This study is part of the Groundwater Resources Program funded by the USGS Office of Groundwater. The report documenting and describing grid generation is: Burns, E.R., Morgan, D.S., Peavler, R.S., and Kahle, S.C., 2010, Three-Dimensional Digital Geomodel of the Columbia Plateau Regional Aquifer System, Idaho, Oregon, and Washington: U.S. Geological Survey Scientific Investigations Report 2010-5246. 201010 publication date Complete None planned -121.844958 -115.367389 48.419451 44.261075 None geomodel Columbia Plateau Regional Aquifer System CPRAS Columbia Plateau overburden inlandWaters None Oregon Washington Idaho Pacific Northwest Columbia River Basin None The U.S. Geological Survey should be acknowledged as the data source in products derived from these data. Erick Burns U.S. Geological Survey Hydrologist mailing and physical address

2130 SW 5th Avenue

Portland OR 97201 USA 503-251-3250 N/A 503-251-3470 eburns@usgs.gov (Warning: Although accurate at the time of production, this information may have become obsolete. See the Metadata_Reference_Information section for a current contact.) http://water.usgs.gov/GIS/browse/obthk_f.jpg Illustration of dataset JPEG Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 3; ESRI ArcCatalog 9.3.1.3500 The resulting geomodel integrates a large number of different types of data to create a fully-consistent three-dimensional representation of the large-scale geometry of the Columbia Plateau Regional Aquifer System. As such, it is the synthesis of the best current understanding gained from previous studies at a variety of scales. Its error is quantifiable (fig. 11a-d in report), with the error being a function of the amount of data. The following list of shortcomings should be considered when using the results of this study: There are errors in the data used to construct the surfaces. This is known because some studies did not agree on stratigraphic interpretations. These errors may cause bias in the interpreted surfaces. Many of the picks made for particular units are inferential, based on previous work, which may be the source of some errors. In most cases, the data are not closely enough spaced to resolve features below the scale of the trend model. Generally, error increases with depth due to limited amounts of data in many areas. This is evidenced in the residual histograms (fig. 11 a-d in report). The Older Bedrock Unit top has some bias, and may be underestimated in the north and northwest where Columbia River Basalt Group depositional style has changed from flood basalt to intra-canyon flows. Error increases with distance from data. The error implied by the residual histograms may be misleading very far from data since the implicit assumption is that the trend surface is correct on average. Error in heavily folded or faulted areas is greater than for smoothly varying areas with moderate data support. Our dataset was insufficient to resolve these features. The surfaces and thickness are modeled from smooth trend surfaces representing unit tops and consequently result in smooth tops where buried. The modeled values represent expected values at any subsurface location, but the true value will likely be somewhat different. Confidence that a unit will be encountered within a given range of elevations may be computed from the residuals. Quality assurance was confirmed by project hydrologist. All raster layers of the geomodel were inspected for overlaps, completeness, and logical consistency. Data are complete. Raster cellsize is 500 feet and all raster cells align with the other rasters in the geomodel. Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD83). Vertical coordinate information is referenced to the North American Vertical Datum of 1988 (NAVD88). Compile project data from sources listed below. See report for details on how each source was used. Bela, J.L., compiler, 1982, Geologic and neotectonic evaluation of north-central Oregon-The Dalles 1 degree by 2 degree quadrangle: Oregon Department of Geology and Mineral Industries Geological Map Series GMS-27, 2 sheets, scale 1:250,000. Bjornstad, B.N., Babcock, R.S., and Last, G.V., 2007, Flood basalts and Ice Age floods: Repeated late Cenozoic cataclysms of southeastern Washington, in Stelling, P., and Tucker, D.S., eds., Floods, Faults, and Fire: Geological Field Trips in Washington State and Southwest British Columbia: Geological Society of America Field Guide 9, p. 209-255. Cleveland, W.S., E. Grosse, and W.M. Shyu, 1992. "Local Regression Models," Statistical Models in S, Ch. 8, pp. 309-376, Wadsworth & Brooks/Cole Advanced Books & Software, Pacific Grove, California, USA. Conlon, T., 2006, Columbia River Basalt Stratigraphy in the Pacific Northwest website, http://or.water.usgs.gov/projs_dir/crbg/, accessed April 29, 2008. Deutsch, C.V., 2002, Geostatistical Reservoir Modeling, Applied Geostatistics Series, Oxford University Press, New York, NY. Davies-Smith, A., Bolke, E.L., and Collins, C.A. 1988, Geohydrology and digital simulation of the ground-water flow system in the Umatilla Plateau and Horse Heaven Hills area, Oregon and Washington: U.S. Geological Survey Water-Resources Investigation Report 87-4268, 72 p. Drost, B.W., and Whiteman, K.J., 1986, Surficial geology, structure, and thickness of selected geohydrologic units in the Columbia Plateau, Washington: U.S. Geological Survey Water-Resources Investigations Report 84-4326, 11 sheets. Drost, B.W., Whiteman, K.J., and Gonthier, J.B., 1990, Geologic framework of the Columbia Plateau Aquifer System, Washington, Oregon, and Idaho: U.S. Geological Survey Water-Resources Investigations Report 87-4238, 10 p., 10 sheets. Gonthier, J.B., 1990, Geology, structure, and thickness of the hydrogeologic units in part of the Columbia Plateau, Oregon: U.S. Geological Survey Water-Resources Investigations Report 86-4001, 6 sheets. Jenks, M.D., Niewendorp, C.A., Ferns, M.L., Madin, I.P., Staub, P.E., and Ma, L., 2006, Oregon Geologic Data Compilation, Version 3: Oregon Department of Geology and Mineral Industries, at http://www.oregongeology.com/sub/ogdc/, accessed March 28, 2008. Jones, M.A., Vaccaro, J.J., and Watkins, A.M., 2006, Hydrogeologic framework of sedimentary deposits in six structural basins, Yakima River basin, Washington: U.S. Geological Survey Scientific Investigations Report 2006-5116, 24 p. Jones, M.A., and Vaccaro, J.J., 2008, Extent and depth to top of basalt and interbed hydrogeologic units, Yakima River basin aquifer system, Washington: U.S. Geological Survey Scientific Investigations Report 2008-5045, 22 p. Kahle, S.C., Olsen, T.D., and Morgan, D.S., 2009. Geologic setting and hydrogeologic units of the Columbia Plateau Regional Aquifer System, Washington, Oregon, and Idaho: U.S. Geological Survey Scientific Investigations Map 3088, 1 sheet. (Also available at http://pubs.er.usgs.gov/usgspubs/sim/sim3088.) Leek, F., 2006, Hydrogeological characterization of the Palouse Basin Basalt Aquifer System, Washington and Idaho: Washington State University, Master of Science in Engineering thesis, 38 p. Lindsey, K, Tolan, T., Nielson, M., and Loper, S., 2007, Geologic framework of the suprabasalt sediment aquifer system, Columbia Basin Ground Water Management area of Adams, Franklin, Grant, and Lincoln Counties, Washington, Edition 1, August 2007, variously paginated. Packard, F.A., Hansen, A.J., Jr., and Bauer, H.H., 1996, Hydrogeology and simulation of flow and the effects of development alternatives on the basalt aquifers of the Horse Heaven Hills, south-central Washington: U.S. Geological Survey Water-Resources Investigations Report 94-4068, 92 p. Reidel, S.P., Johnson, V.G., and Spane, F.A., 2002, Natural gas storage in basalt aquifers of the Columbia Basin, Pacific Northwest USA: a guide to site characterization: Pacific Northwest National Laboratory, Richland, Washington, variously paginated, at http://www.pnl.gov/main/publications/external/technical_reports/PNNL-13962.pdf Richmond, G.M., Fryxell, R., Neff, G.E., and Weis, P.L., 1965, The Cordilleran ice sheet of the northern Rocky Mountains, and the related Quaternary history of the Columbia Plateau, in Wright, H.E., Jr., and Frey, D.G., eds., The Quaternary of the United States: Princeton, New Jersey, Princeton University Press, p. 231-242. Snyder, D.T., and Haynes, J.V., 2010. Groundwater conditions during 2009 and changes in groundwater levels from 1984 to 2009, Columbia Plateau Regional Aquifer System, Washington, Oregon, and Idaho: U.S. Geological Survey Scientific Investigations Report 2010-5040, 12 p. (Also available at http://pubs.er.usgs.gov/ sir/2010/5040/.) State of Washington Office of Financial Management, 2007, Washington's Rank in the Nations Agriculture, 2007 Data Book, http://www.ofm.wa.gov/databook/resources/nt14.asp, accessed June 16, 2009. Swanson, D.A., Anderson, J.L., Bentley, R.D., Byerly, G.R., Camp, V.E., Gardner, J.N., and Wright, T.L., 1979a, Reconnaissance geologic map of the Columbia River Basalt Group in eastern Washington and northern Idaho: U.S. Geological Survey Open-File Report 79-1363, 26 p., 12 sheets, scale 1:250,000. Swanson, D.A., Anderson, J.L., Camp, V.E., Hooper, P.R., Taubeneck, W.H., and Wright, T.L., 1981, Reconnaissance geologic map of the Columbia River Basalt Group, northern Oregon and western Idaho: U.S. Geological Survey Open-File Report 781-797, 35 p. Swanson, D.A., Brown, J.C., Anderson, J.L., Bentley, R.D., Byerly, G.R., Gardner, J.N., and Wright, T.L., 1979b, Preliminary structure contour maps of the top of the Grande Ronde and Wanapum Basalts, eastern Washington and northern Idaho: U.S. Geological Survey Open-File Report 79-1364, 2 sheets, scale 1:500,000. Swanson, D.A., Wright, T.L., Hooper, P.R., and Bentley, R.D., 1979c, Revision in the stratigraphic nomenclature of the Columbia River Basalt Group: U.S. Geological Survey Bulletin 1457-G, 59 p. Tolan, T.L., Reidel, S.P., Beeson, M.H., Anderson, J.L., Fecht, K.R., and Swanson, D.A., 1989, Revisions to the estimates of the areal extent and volume of the Columbia River Basalt Group, in Reidel, S.P., and Hooper, P.R., eds., Volcanism and tectonism in the Columbia River flood-basalt province: Geological Society of America Special Paper 239, p. 1-20. Tolan, T., Lindsey, K., Nielson, M., and Loper, S., 2007, Geologic framework of selected sediment and Columbia River Basalt units in the Columbia Basin Ground Water Management area of Adams, Franklin, Grant, and Lincoln Counties, Washington, Edition 2, August 2007, variously paginated. U.S. Department of Agriculture, 2007, The Census of Agriculture, http://www.agcensus.usda.gov/Publications/2007/Online_Highlights/Rankings_of_Market_Value/Washington/index.asp, accessed June 16, 2009. Waitt, R.B., Jr., and Thorson R.M., 1983, The Cordilleran ice sheet in Washington, Idaho, and Montana, in Wright, H.E., and Porter, S.C., eds., Late-Quaternary environments of the United States, v. 1.: Minneapolis, University of Minnesota Press, p. 53-70. Washington Division of Geology and Earth Resources, 2005, Digital 1:100,000-scale geology of Washington State, version 1.0: Washington Division of Geology and Earth Resources Open-File Report 2005-3, at http://www.dnr.wa.gov/ResearchScience/Topics/GeologyPublicationsLibrary/Pages/pub_ofr05-3.aspx, accessed September 8, 2006. Whiteman, K.J., Vaccaro, J.J., Gonthier, J.B., and Bauer, H.H., 1994, The hydrogeologic framework and geochemistry of the Columbia Plateau aquifer system, Washington, Oregon, and Idaho: U.S. Geological Survey Professional Paper 1413-B, 73 p. Wilson, M.S., Dyman, T.S., and Condon, S.M., 2008, Evaluation of Well-Test Results and the Potential for Basin-Center Gas in the Columbia Basin, Central Washington, Chapter 4 of Geologic Assessment of Undiscovered Gas Resources of the Eastern Oregon and Washington Province: U.S. Geological Survey Digital Data Series DDS-69-0. Zientek, M.L., Derkey, P.D., Miller, R.J., Causey, J.D., Bookstrom, A.A., Carlson, M.H., Green, G.N., Frost, T.P., Boleneus, D.E., Evans, K.V., Van Gosen, B.S., Wilson, A.B., Larsen, J.C., Kayser, H.Z., Kelley, W.N., and Assmus, K.C., 2005, Spatial databases for the geology of the Northern Rocky Mountains-Idaho, Montana, and Washington: U.S. Geological Survey Open-File Report 2005-1235, 201 p., at http://pubs.usgs.gov/of/2005/1235/ US Geological Survey, EROS Data Center, National Elevation Dataset (NED) 30-meter digital elevation model. 2010 The obthk_f grid was generated by computing a trend surface for the top of bedrock for all locations buried under significant thicknesses of sedimentary overburden, then stitching together this trend surface with the land surface digital elevation model (DEM) where thicknesses are assumed to be negligible. The DEM is a 500-foot grid that was resampled from a 30-meter National Elevation Dataset (NED) DEM. Taking the difference between the stitched together surfaces and the DEM provides the modeled thickness in feet of the Overburden unit. A value of NULL was assigned to all cells with zero thickness. This is one of four modeled thicknesses. The modeled thicknesses, listed in order from uppermost to lowermost, are (1) obthk_f (modeled thickness of the Overburden unit), (2) smthk_f (modeled thickness of the Saddle Mountains Basalt unit), (3) wnthk_f (modeled thickness of the Wanapum Basalt unit), and (4) grthk_f (modeled thickness of the Grande Ronde Basalt unit). A complete description of geologic units and assumptions are provided in: Burns, E.R., Morgan, D.S., Peavler, R.S., and Kahle, S.C., 2010, Three-Dimensional Digital Geomodel of the Columbia Plateau Regional Aquifer System, Idaho, Oregon, and Washington: U.S. Geological Survey Scientific Investigations Report 2010-5246. 2010 ArcGIS 9.3.1 Buffered the CRB_extent4xconnections.shp by 30,000 feet and used the buffered polygon to clipped the obthk_f grid. 2010 ArcGIS 9.3.1 Raster Grid Cell 2958 3151 1 Lambert Conformal Conic 45.833333 47.333333 -120.500000 45.333333 1640416.666667 0.000000 row and column 500.000000 500.000000 survey feet North American Datum of 1983 Geodetic Reference System 80 6378137.000000 298.257222 North American Vertical Datum of 1988 .001 feet Explicit elevation coordinate included with horizontal coordinates Grid values represent modeled thickness of the Overburden geomodel unit, in feet. Burns, E.R., Morgan, D.S., Peavler, R.S., and Kahle, S.C., 2010, Three-Dimensional Digital Geomodel of the Columbia Plateau Regional Aquifer System, Idaho, Oregon, and Washington: U.S. Geological Survey Scientific Investigations Report 2010-5246. U.S. Geological Survey Ask USGS -- Water Webserver Team mailing address

445 National Center

Reston VA 20192 USA 1-888-275-8747 (1-888-ASK-USGS) http://water.usgs.gov/user_feedback_form.html Downloadable Data Although these data have been used by the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of these data, software, or related materials. The use of firm, trade, or brand names in this report is for identification purposes only and does not constitute endorsement by the U.S. Geological Survey. The names mentioned in this document may be trademarks or registered trademarks of their respective trademark owners. ArcInfo Grid PKZIP compression Winzip 35.673 http://water.usgs.gov/GIS/dsdl/ColumbiaRiverPlateauGeomodel.zip None. This dataset is provided by USGS as a public service. 20100824 U.S. Geological Survey Ask USGS -- Water Webserver Team mailing address

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Reston VA 20192 USA 1-888-275-8747 (1-888-ASK-USGS) http://answers.usgs.gov/cgi-bin/gsanswers?pemail=h2oteam&subject=GIS+Dataset+col_riv_obthk_f FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998 local time