WATERSHED SCALE CHARACTERIZATION OF GLACIAL AND BEDROCK AQUIFERS IN EASTERN NEBRASKA

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1 WATERSHED SCALE CHARACTERIZATION OF GLACIAL AND BEDROCK AQUIFERS IN EASTERN NEBRASKA Lawrence, KS May 21, 2015 Jared D. Abraham, MSc., Senior Research Geophysicist, XRI James C. Cannia, P.G., Senior Geologist, XRI Kathleen Cameron, P.G. Eastern Nebraska Water Resources Assessment (ENWRA) Project Coordinator Theodore H. Asch, PhD, P.Gp., Research Geophysicist, XRI

2 COAUTHORS Clint Carney, MSc., P.G. Geologist Andrew Genco, MSc. Geophysicist Rachel Woolf, MSc. Geophysicist Todd Meglich, BSc. Geophysicist Kristen Pierce, BSc. Geophysicist Trevor Irons, PhD. - Research Geophysicist Greg Steele, MSc., P.G., Senior Hydrologist

3 6 Eastern Nebraska Natural Resources Districts (NRD) Formed in 2006 to assess the glaciated area Agency partners: US Geological Survey (USGS), University of Nebraska Lincoln Conservation Survey Division (CSD), Nebraska Department of Natural Resources (NDNR), and Nebraska Department of Environmental Quality (NDEQ) 3 pilot study sites to test toolsets First use of helicopter mapping in 2007 Application of the flight technology evolved over time

4 Groundwater resources are more limited in eastern Nebraska Much of the groundwater supply in eastern Nebraska is from aquifers that are within & below glacial deposits They can be laterally discontinuous, have highly variable geometry, and are heterogeneous making them very complex to map Delineation of these aquifers is critical for management purposes The quantity of water may be limited due to the spatially confined nature of the aquifers Natural water quality varies in different aquifers and human induced (example nitrates) may infiltrate to these aquifers and degrade their quality

5 CROSS SECTION ACROSS NEBRASKA The Groundwater Atlas of Nebraska Resource Atlas No. 4b/2013 Third (revised) Edition Conservation and Survey Division School of Natural Resources Institute of Agriculture and Natural Resources University of Nebraska - Lincoln

6 RECON FLIGHTS AEM survey AEM data processing incorporates existing data along flight lines Test holes logged by state geologists since 1940 Deep oil and gas well cores Study sites local studies and geologic reports Registered well logs Legend ENWRA Oct 2014 Flight Lines LENRD Grid Fall 2014 Planned Spring 2015 Flights Rivers ENWRA NRDs Existing ENWRA Pilot and Partner Studies Lewis & Clark Lower Elkhorn Lower Platte North Lower Platte South Nemaha Papio-Missouri River

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8 E. AUKEN, U. OF AARHUS, DENMARK

9 FLIGHT LINE PLANNING Lines Planned along CSD Cross Sections Pipeline data were acquired from Platts ( CSD/ENWRA assisted in acquiring data on public power systems Auburn Board of Public Works, Burt County Power District, Butler County Power District, Cedar-Knox Power District, City of Fremont, Cornhusker Public Power District, Cuming County Power District, Elkhorn Rural Public Power District, Lincoln Electric Systems, Loup Power District, Nebraska Public Power District, Nemaha-Marshall Electric Cooperative, Norris Public Power District, North Central Public Power District, Northeast Nebraska Public Power District, Omaha Public Power District, Polk County Rural Public Power District, Seward County Public Power District, Stanton County Public Power District Flight lines were adjusted to optimize data collection

10 AEM EASTERN NEBRASKA , ,430 line-km 50 km 2,532 line-km 1,100 line-km 50 km October th, days of data collection 1 weather day (wind Oct 17) April th, days of data collection 2 weather day (rain April 18-19)

11 IN FIELD QA/QC AND INVERSION Within 24 hours we invert SkyTEM 508 system-first time gate 12 μsec 3.0 μsec wide and last time gate of 10.0 msec Aarhus Workbench SCI was used with 30 layer smooth inversion. First layer 5 m.

12 BACKGROUND BOREHOLE DATA

13 CSD HISTORICAL CROSS SECTIONS

14 CSD CROSS SECTIONS

15 RESISTIVITY VERSUS LITHOLOGY AND AQUIFER MATERIALS Non Aquifer Marginal Aquifer Principal Aquifer Coarse Aquifer 39 CSD boreholes with lithology and resistivity geophysical logs ~209,000 individual measurements

16 LITHOLOGY VERSUS AQUIFER MATERIAL Non Aquifer Marginal Aquifer

17 LITHOLOGY VERSUS AQUIFER MATERIAL 21 to 50 Ohm-m Principal Aquifer Coarse Aquifer

18 CSD 5 GT METERS OFF LINE

19 EXAMPLE CROSS SECTION

20 300 m 20 km

21 STRUCTURE IN THE PALEOZOIC 400 m 15 km

22 WATER QUALITY CHANGES

23 3D VIEW OF THE RESITIVITY OF ENWRA

24 300 m 20 km

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26 AEM VERSUS CSD CROSS SECTION 111 km (69 mile) cross section with 27 test holes totaling 2,057 m(average depth of 76 m(250 ft)) $160,000 AEM cost (Average depth 304 m (1,000 ft)) $44,464 28% of the cost of drilling

27 3D OF THE 2014 AEM IN LENRD North

28 3D OF THE 2014 AEM IN LENRD North

29 3D OF THE 2014 AEM IN LENRD North

30 3D OF THE 2014 AEM IN LENRD North

31 3D OF THE 2014 AEM IN LENRD North

32 GOOGLE EARTH FILES

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35 SURVEY CONCLUSIONS Aquifer resources vary considerably within the Quaternary and Tertiary system. The aquifer material is thicker in the western part of the ENWRA. The Quaternary and Tertiary material act as the principal aquifer in the west. Non-aquifer (aquitard) materials are abundant in the central and eastern portions of the survey area, with till and loess sequences exceeding 60 m. The full sequence of Cretaceous strata present in eastern Nebraska was detected by the AEM system. The full thickness of the Dakota (Kd) is revealed in the AEM survey. The AEM indicated potential areas of development. The structure in the Paleozoic was mappable in southeastern NE The line spacing at 3 miles grids can be used to delineate groundwater management areas. The reconnaissance line spacing for the ENWRA flights shows areas of interest for future work.

36 ACKNOWLEDGMENTS Susan Olafsen Lackey- Nebraska Conservation Survey Division (CSD), University of Nebraska Lincoln, School of Natural Sciences Rick Wozniak and Curt Becker Lower Elkhorn Natural Resources District (LENRD) Alan Stack, Pilot Native American Helicopters Jason Marcil, SkyTEM, Project Manager Devbrio Géophysique Inc. B.J. Crocker, Owner - Native American Helicopters Flemming Effersø, CEO SkyTEM Bill Brown, North American Sales SkyTEM Andrea Viezzoli, Aarhus Geophysics

37 CONTACTS Jared D. Abraham, MSc. Senior Research Geophysicist Golden, CO (303) Kathleen Cameron, P.G. ENWRA Project Coordinator Lincoln, NE (402)