U.S. Department of the InteriorU.S. Geological Survey

Preliminary Results of Dye- Tracer Test at the B4 Area and Offsite Wells

Dye Injection 11/13/07

Results up to 1/8/08 (8 weeks)

Preliminary Results

2000 Results

Air Force Plant 6Dobbins Air Force

Reserve Base

B-4

Area

SouthernPolytechnic

StateUniversity

Life University

Rottenwood

Creek

Sites with TCE detections

MW0s2

Preliminary Results

Objective and Approach

Better understand ground-water movement in deep bedrock from B4 to offsite area

Selected two on-site wells (OB203 and RW203) that were located close enough to each other for an initial test.

Also included off-site bedrock wells in the test that were located downgradient from the injection well.

Preliminary Results

Tracer Test Location Map

Preliminary Results

Sampling Frequency

Weekly sampling at RW203

Monthly sampling at other sites

Preliminary Results

Pre-Injection Background Sampling

Fluorescein (Acid Yellow 73) Eosine (Acid Red 87) Rhodamine WT (Acid Red

388) Sulphorhodamine B (Acid

Red 52) Tinopal CBS-X (Fabric

brightening agent 351) Solophenol 500% (Direct

Yellow 96) D&C Red #28 FD&C Red #3 D&C Green #8 Palanil Luminous Red G Lissamine FF

Preliminary Results

Injection 11/13/07 @ 1300

Set 1-inch PVC to 90 ft 1 gal #3 Red (pre-mixed) Followed by 15 gal water

(Flowmeter indicated no flow below 105 feet)

Preliminary Results

Downgradient Monitoring Well RW203

Downward flow between 100 and 139’

Zero flow below 139’

Dye receptor placed at 105’

Preliminary Results

Results: Injection 11/13/07 @ 1300

ob203a RW203

92’ 380’ 880’

SCT2 SCT1

A

B

C

A

B

C

SCT3

(420-560)

(88-105)

(521-543)

(434-457)

(85-125)

(65-95)

(139)

(100)

(119-198)

Depths in parentheses(not to scale)

Preliminary Results

Results – 3 Days

ob203a RW203

92’ 380’ 880’

SCT2 SCT1

A

B

C

A

B

C

SCT3

Not sampled Not sampled

30446

(420-560)

(88-105)

(521-543)

(434-457)

(85-125)

(65-95)

(119-198)

Preliminary Results

Results – 2 Weeks

ob203a RW203

92’ 380’ 880’

SCT2 SCT1

A

B

C

A

B

C

SCT3ND

ND ND (.030)?

22973

(420-560)

(88-105)

(521-543)

(434-457)

(85-125)

(65-95)

(119-198)

Preliminary Results

Results – 5 Weeks

ob203a RW203

92’ 380’ 880’

SCT2 SCT1

A

B

C

A

B

C

SCT3ND

0.365 21.4

ND (.050)

ND

ND

6650

(420-560)

(88-105)

(521-543)

(434-457)

(85-125)

(65-95)

(119-198)

Preliminary Results

Results – 8 Weeks

ob203a RW203

92’ 380’ 880’

SCT2 SCT1

A

B

C

A

B

C

SCT3ND

15.6 300.2

.916

? (not sampled)

ND

201

(420-560)

(88-105)

(521-543)

(434-457)

(85-125)

(65-95)

(119-198)

Preliminary Results

Map 8-Weeks

Preliminary Results

All Results

LocationDistance

(ft) 3-DAYS 2-WK 3-WK 5-WK 8-WK

RW-203 (100, 139) 92 30446 22973 6990 6650 201

SCT2-C (85-125) 384   ND   .365 (.292) 15.673 (8.937)

SCT2-A (521-543) 384       (0.05) (0.916)

SCT-2B (434-457) 384       (ND)  

SCT-3 (65-95) 400   ND (ND)   ND (ND) ND (ND)

MW0S-2R (133) 528   ND (ND)   ND (ND) ND (ND)

MWOS-03 (11-21) 531   ND (ND)   ND (ND) ND (ND)

Trib-1 633   ND (ND)   ND (ND) ND (ND)

SCT1-C (88-105) 879   0.03   21.455 (4.272) 300.24 (12.712)

SCT1-A (420-560) 879       ND ND

Preliminary Results

What would cause such a highly constrained flow path?

Why is the flow rate so high?

Preliminary Results

I

IV

III

II

I-B

Dominate strike of foliation = green, joints = red

Preliminary Results

Parting Plane

Preliminary Results

Findings (so far)

Fastest GW movement is through transition zone with flow rates on the order of 25 to 50 ft/day

GW movement appears to be strongly constrained along discontinuities formed parallel to foliation/layering (i.e. parting planes and lithologic contacts)

A downward hydraulic gradient in the area appears to influence deeper GW movement

Preliminary Results

Tracer Test Continued…

Stay tuned Sampling every 3 weeks Will continue to sample until dye passes

through system or we are satisfied with results

Other zones/wells may be tested