MARINE GEOPHYSICAL PROVE-OUT AND SURVEY AT FLAG LAKE BOMBING RANGE BARKSDALE AIR FORCE BASE, LOUISIANA

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Hackworth 1 1 FPM Geophysical & UXO Services, 706 S. Illinois Ave.

hackworth@fpm-geo.com 2 2 CES/CEAOR, 334 Davis Ave.

1 MARINE GEOPHYSICAL PROVE-OUT AND SURVEY AT FLAG LAKE BOMBING RANGE BARKSDALE AIR FORCE BASE, LOUISIANA Garrick Marcoux 1, Wallace Robertson 2, Boban Stojanovic 1, Jeffrey B. Hackworth 1 1 FPM Geophysical & UXO Services, 706 S. Illinois Ave., Ste D-104, Oak Ridge, TN g.marcoux@fpm-geo.com, b.stojanovic@fpm-geo.com, j.hackworth@fpm-geo.com 2 2 CES/CEAOR, 334 Davis Ave. West, Suite 208, Barksdale AFB, LA wallace.robertson@barksdale.af.mil Joint Services Environmental Management Conference Columbus, OH May 22, 2007

2 Introduction Extensive gunnery and bombing training occurred across the East Reservation throughout the mid 1930s and through the 1940s. Work contracted by the U.S. Air Force Center for Environmental Excellence (AFCEE) through Program Contract No.: F D-8601, Task Orders 0013, 0025

3 Introduction (Cont d) UXO Geophysical Site Investigations at 5 East Reservation Bomb Ranges: Update DOD Range Inventory Determine which AOC s s pose greatest hazard to Public Safety and Environment EPA s s Triad Approach Used: Systematic Planning Help manage uncertainty Dynamic Work Plan Adjustments / decisions made in the field Real-Time Measurement Technologies Geophysical and GPS data Web-Enabled GIS

4 Introduction (Cont d) Approximately 600 acres of the 1,100-acre Flag Lake Range is occupied by Flag Lake.

5 Introduction (Cont d) Features visible in historical photography may represent bomb craters.

potential snags and impact hazards Collect and process magnetometer (G-882

6 Marine Geophysical Prove-out out (MGPO) 1) Identify suitable MGPO location Evaluate lake conditions including depth (survey rod and fathometer) and potential snags and impact hazards Collect and process magnetometer (G-882 marine magnetometer) and Side Scan Sonar (SSS) (600-KHz Sea Scan) data across the proposed MGPO area

7 Marine Geophysical Prove-out out 2) Prepare MGPO for geophysical survey Prepare seed items (UXO simulants) Distribute simulants and survey locations with GPS

8 Marine Geophysical Prove-out out Conduct MGPO survey with: Geometrics G-882 cesium vapor magnetometer Geonics Ltd. EM61-S submersible time-domain EM system Advanced Geosciences, Inc. SuperSting R8 Electrical Resistivity Marine Logging System Geophysical Survey Systems, Inc. (GSSI) Terra-Search 3000 Ground Penetrating Radar system with 200- and 400-MHz antennas Sea Scan 600-KHz SSS system Raytheon DE719D Precision Fathometer (200-KHz) Positional data obtained via Trimble Pro XRS receiving Omnistar realtime differential correction (sub-meter accuracy)

software (MagLog) Predictable response (cesium vapor magnetometers are a recognized

9 MGPO Instrument Results Geometrics G-882 cesium vapor magnetometer Detected all seed items exceeding 15-lbs with high degree of accuracy Reliable hardware and acquisition software (MagLog) Predictable response (cesium vapor magnetometers are a recognized standard for UXO detection) Tow fish not suited for very shallow water (potential snag hazard)

10 MGPO Instrument Results Geometrics G-882 cesium vapor magnetometer

11 MGPO Instrument Results Geonics Ltd. EM61-S submersible time-domain EM system Cumbersome profile to tow through water (Lack of streamlining makes instrument susceptible to snag and breakage without additional engineering controls to safeguard coil) Not able to detect any seed items

12 MGPO Instrument Results Geonics Ltd. EM61-S submersible time-domain EM system

13 MGPO Instrument Results Advanced Geosciences, Inc. SuperSting R8 Electrical Resistivity Marine Logging System Not able to detect any seed items GPS interoperability is limited

14 MGPO Instrument Results Advanced Geosciences, Inc. SuperSting R8 Electrical Resistivity Marine Logging System

200- and 400-MHz antennas Good correlation with seed items

15 MGPO Instrument Results Geophysical Survey Systems, Inc. (GSSI) Terra-Search 3000 Ground Penetrating Radar system with 200- and 400-MHz antennas Good correlation with seed items Provides accurate water depth Some signal penetration into sediments

16 MGPO Instrument Results Geophysical Survey Systems, Inc. (GSSI) Terra-Search 3000 Ground Penetrating Radar system with 200- and 400-MHz antennas

17 MGPO Instrument Results Sea Scan 600-KHz SSS system Provides information about lake bottom across a relatively wide swath Ability to detect seed items was limited Not suitable for shallow water or in areas of potential snag hazards

18 MGPO Instrument Results Raytheon DE719D Precision Fathometer (200- KHz) Provides depth information that can be output to ASCII format Model used for survey seemed to be easily fooled and required periodic sensitivity adjustments

19 MGPO Conclusions Instrument selection for production work dependant on ability to detect suspected ordnance as well as practical issues related to physical hazards associated with towing instruments through shallow water. Magnetometer and GPR selected for follow-on production work.

20 What Next?

21 Production work completed in April 2007 Flag Lake Harmon Lake Approximately 100 km of collocated magnetometer and GPR transect and grid data collected. Approximately 16 km of collocated magnetometer and GPR transect data collected.

22 Production Survey Equipment 16-foot bass boat Geometrics G-858 cesium vapor magnetometer GSSI Terra-Search 3000 Ground Penetrating Radar system with 200-MHz antenna Trimble Pro XRS GPS Inflatable rafts Sunscreen

23 Production Survey Equipment Use of off the shelf hardware and supplies added value to field effort. Inflatable rafts provide sensor platform that is virtually transparent to acquisition signals, and they bounce off cypress trees. Float noodles serve to minimize cable chafing while providing protection against snags. Bass boat rented on Base.

24 Production Survey Equipment Single GPS receiver used to simultaneously position magnetometer and GPR data as well as provide navigational data. Serial Y-cable ($3.50) eliminated need for second or third GPS receiver, and simplified data acquisition.

25 Magnetometer Data Preliminary target picking at Flag Lake yielded 110 targets exceeding 5 nt/m.

26 Magnetometer Data Preliminary target picking at Harmon Lake yielded 75 targets exceeding 5 nt/m.

27 GPR Data Correlation to magnetic anomalies is a multi-step process including QA of positional data and is currently a work in progress.

UTM coordinates allow comparison of GPR target location to magnetic target location GPR Data Magnetic anomaly positions are imported into GPR database to provide

28 UTM coordinates allow comparison of GPR target location to magnetic target location GPR Data Magnetic anomaly positions are imported into GPR database to provide information on target depth and location as well as to provide information on the presence of bomb craters. Water column Sub-bottom reflections Location of magnetic targets

29 Lessons Learned Summary & Conclusions Integration of multiple methods increases confidence when evaluating suspected ordnance targets. There is no substitute for understanding site conditions when planning marine field work. Use of off the shelf technologies adds value by reducing the need for engineered solutions. Successful marine survey highly dependant on site conditions. Wind, water depth, vegetation and biological hazards are important factors when planning for survey. Reconnaissance of survey area is critical for planning purposes. Acquire water depth data prior to planning survey.

Main Menu. Summary: Introduction:

Main Menu. Summary: Introduction: UXO Detection and Prioritization Using Combined Airborne Vertical Magnetic Gradient and Time-Domain Electromagnetic Methods Jacob Sheehan, Les Beard, Jeffrey Gamey, William Doll, and Jeannemarie Norton,