Response to CSLC Letter 071017 - dtsc-topock.com · Well ID Recommendation in August 2015 Letter Approval Conditions or Requests in DTSC’s April 6, 2017 Letter PG&E’s Reply, July

Pacific Gas and Electric Company

Curt Russell Topock Site Manager GT&D Remediation

Topock Compressor Station 145453 National Trails Hwy Needles, CA 92363

Mailing Address P.O. Box 337 Needles, CA 92363

760.326.5582 Fax: 760.326.5542 Email: [email protected]

July 31, 2017

Mr. Aaron Yue, Project Manager Department of Toxic Substances Control 5795 Corporate Avenue Cypress, CA 90630

Subject: Response to DTSC’s Geological Services Unit April 6, 2017 Memorandum titled Proposal for Alternative Groundwater Sampling Trial, Pacific Gas and Electric, Topock Compressor Station

Dear Mr. Yue:

Pacific Gas and Electric (PG&E) has reviewed the approval conditions and requests in the technical memorandum from the California Department of Toxic Substances Control’s (DTSC) Geological Services Unit (GSU) dated April 6, 2017. The DTSC GSU April 2017 memorandum is in response to PG&E’s 2015 alternative sampling approach recommendations for long screen bedrock monitoring wells.

The attached table summarizes PG&E’s understanding and reply to the April 2017 technical memorandum. With a few exceptions, PG&E will begin to implement DTSC’s approval in the Q4 2017 sampling event.

For the exceptions outlined in the table, we would appreciate your review and concurrence by September 1, 2017. We would be glad to use weekly technical calls or ad hoc calls to facilitate your review. Please contact me at (760) 791‐5884 if you have any questions or comments regarding this response.

Sincerely,

Curt Russell Topock Site Manager

cc: Chris Guerre/DTSC, Pam Innis/DOI

mailto:[email protected]

Well ID Recommendation in August 2015 Letter

Approval Conditions or Requests in DTSC’s April 6, 2017 Letter PG&E’s Reply, July 31, 2017

MW-23-60 MD; well is already sampled with MD‐capable pump

MD approved with SC, pH profiles Accept ‐ Collect SC & pH profiles; begin MD sampling in Q4 2017.

MW-23-80 MD; well is already sampled with MD‐capable pump

MD approved with SC, pH profiles Accept ‐ Collect SC & pH profiles; begin MD sampling in Q4 2017.

MW-24BR MD Trial, with dedicated bladder pump, at 408 feet

MD approved with new Flow Testing to verify MD depths

Request for deviation from April 2017 Letter: Continue 3V sampling.

This is a low‐yield deep well with a 60‐foot screen in bedrock. Historical data (CH2M 2008) measured very low hydraulic conductivity. A dedicated electric submersible pump was used since 2014, due to biofouling concern at this well.

MW-48 MD Trial with dedicated tubing 4Q 2015 through 2016

MD approved with SC profile and periodic purge dry

Accept ‐ Collect SC pH profiles; begin MD sampling in Q4 2017. Note that MD may not maintain limited drawdown so return to “purge dry then sample” could be outcome of trial.

MW-57-070 Change to MD with pump at mid‐ screen MD approved with SC profile

Accept ‐ Collect SC pH profiles; begin MD sampling in Q4 2017.

MW-57-185 MD Trial with pump at 171 feet Trial of MD at 2 depths 150 & 171 feet vs. 3V purge, SC profile

Accept ‐ Collect SC profile and begin sampling trial in Q4 2017.

MW-58BR

Continue current MD sampling purge approach, with pump at 190 feet

Reconstruct well with screens corresponding to former packer placement in bedrock open bore, add flood protection

Accept – Evaluate and add flood protection, with a request for deviation below. Request for deviation from April 2017 Letter: Continue current sampling. Remedy use is planned with current sampling approach after several multilevel configurations in past.

MW-60BR-245 MD Trial, with pump at 180 feet

Trial of MD at 2 depths 175 & 238 feet vs. 3V purge, SC profile


MW-61-110 MD, keep pump at 100 feet MD approved with SC profile Accept ‐ Collect SC pH profiles; begin MD sampling in Q4 2017.

MW-62-065 MD from midscreen MD approved with SC profile Accept ‐ Collect SC pH profiles; begin MD sampling in Q4 2017.


MW-64BR

HydraSleeve and MD Trial; continue MD sample collection from middle of saturated borehole and test HS sampling.

Reconstruct well with screens corresponding to former packer placement in bedrock open bore

Request for deviation from April 2017 Letter: Continue current sampling. Remedy use is planned with current sampling approach after several multilevel configurations in past. HS trial request withdrawn.

MW-65-160 Bladder pump since 2014 DTSC directed to add this well. MD approved with SC profile.

Accept ‐ Collect SC profile; begin MD sampling in Q4 2017.

MW-66BR-270 HydraSleeve (HS), from mid screen

HS trial approved with SC profile Request for deviation from April 2017 Letter: Continue current sampling. HS



trial request withdrawn. Continue purge dry then sample

MW-68BR-280 MD from midscreen MD approved with SC profile Accept ‐ Collect SC pH profiles; begin MD sampling in Q4 2017.



MW-70BR-225 MD Trial, with pump, at 215 feet

MD vs. 3V sampling trial approved, with SC profile



MW-72BR-200 MD Trial, with dedicated bladder pump, at 151 feet

Trial of MD at 2 depths 152 & 195 feet vs. 3V purge, SC profile



OW-03S MD Trial, midscreen MD approved with SC profile

Accept ‐ begin MD sampling in Q4 2017, with request for deviation below. Request for deviation from April 2017 Letter: No SC profile for shallow alluvial wells.

TW-01 MD Trial, midscreen MD specific depths need justification, consider flow tests

Justification: See attached 2003 flow tests and sampling for MD/HS trial at 3 depths (170, 205, and 230‐foot depths)

TW-04 MD Trial, midscreen Not in DTSC response Request DTSC approval: Conduct MD vs. 3V trial, MD specific depth 222 feet (log attached), SC profile.

TW-05 MD Trial, midscreen Not in DTSC response

Request DTSC approval: Conduct MD vs. 3V trial, MD specific depth 147 feet (log attached), but No SC profile (well is not screened near bedrock so no SC profile).

MW-60-125, MW-74-240, OW-3S; OW-1S, OW-1M, OW-1D, OW-2S, OW-2M, OW-2D, and OW-5D

Change to MD with pump at mid‐ screen

MD approved with SC profile approved in these wells with 30‐foot or shorter screens.

Accept – begin MD sampling in Q4 2017 and SC profile the deep screen “D” wells, with request for deviation below. Request for deviations from April 2017 Letter: 1) No SC profile for shallow alluvial wells screened above bedrock. 2) logs (attached) were reviewed to select MD sampling depths (feet bgs) for Trial in longer screen wells, because flow testing not practical in 2-inch wells:

• OW‐5S 107 feet, OW‐5M 240 feet • CW‐1M 175 feet, CW‐1D 267 feet • CW‐2M 177 feet, CW‐2D 317 feet • CW‐3M 197 feet, CW‐3D 297 feet • CW‐4M 150 feet, CW‐4D 280 feet

OW-5S, OW-5M, CW-1M, CW-1D, CD-2M, CW-2D, CW-3M, CW-3D, CW-4M, CW-4D

MD Trial, midscreen MD Trial approved with SC profile and flow testing to select MD sampling depths in these wells with 40 to 50‐foot screens



PGE-07BR MD Trial, with dedicated bladder pump, at 275 feet

MD approved with new Flow Testing to verify MD depths

Request for deviation from April 2017 Letter: Continue 3V sampling. This is a deep well with an approximate 50‐foot packed‐off screen inbedrock.Historical data (CH2M 2008) measured verylow hydraulic conductivity. Bedrock Crresults are ND.

PGE-08 3V Explore feasibility of packer removal then video logging, flow testing

Request for deviation from April 2017 Letter: Continue 3V sampling. This is a former supply well with an approximate 150‐foot screen in bedrock. Existing packer blocks access to screen. Packer is damaged and lodged in place (CH2M 2008). All results are ND for chromium.

CH2M HILL 2008. Summary Report for Hydraulic Testing in Bedrock Wells, PG&E Topock Compressor Station, Needles, California. January.

MD minimal drawdown sampling method HS HydraSleeve sampling method 3V three volume purge sampling method

RESPONSE TO DTSC PROPOSAL FOR ALTERNATIVE GROUNDWATER SAMPLING TRIAL MEMORANDUM DATED APRIL 6, 2017, PG&E TOPOCK COMPRESSOR STATION

Attachments


Attachment 1 Topock Monitoring Well Location Maps

MW-71-035

MW-72-080MW-73-080

MW-60BR-245

MW-15

MW-40S

MW-31-60

IW-2

MW-8

MW-1

MW-5

IW-3

MW-6

MW-7MW-4

MW-58-065

MW-61-110

MW-64BR

MW-63-065

MW-62-065

MW-60-125

MW-59-100

MW-58BRMW-57-050

MW-37S

OW-3S

MW-72BR-200

See Inset A

MW-40D

MW-37D

MW-41DOW-3MOW-3D

MW-62-190MW-62-110

Colorado River

TOPOCKCOMPRESSORSTATION (TCS)

FORMER TCSEVAPORATIONPOND SITE

TCS NEWEVAPORATION

PONDS

Park Moabi R

oad

MOABIREGIONAL

PARK

National Trails Highway

BNSF Railroad

See Inset B

TW-05

TW-04

MW-25

MW-22

MW-18

MW-17

MW-16

MW-49-365MW-49-275

MW-32-020

Park Moabi-4

Park Moabi-3

MW-51MW-26

MW-19

MW-14

MW-13

MW-56DMW-56M

MW-56SMW-53DMW-53M

MW-52D

MW-41SMW-41M

MW-55-045MW-55-120

MW-54-085MW-54-140MW-54-195

MW-50-095

MW-49-135

MW-43-090MW-43-075MW-43-025

MW-33-210

MW-32-035

MW-28-025

MW-23-060

MW-52MMW-52S

MW-29

MW-21

MW-50-200

MW-47-055MW-47-115

MW-35-060MW-35-135

MW-33-090MW-33-150

MW-28-090

MW-23-080

MW-46-205

MW-33-040

MW-46-175

MW-57-070MW-57-185

MW-30-050

MW-31-135MW-36-020MW-36-040MW-36-050MW-36-070

MW-39-040MW-39-050MW-39-060MW-39-070MW-39-080

MW-44-070

TW-02STW-02D

MW-20-070MW-20-100MW-20-130

MW-27-020MW-27-060

MW-30-030

MW-34-055MW-36-090MW-36-100

MW-39-100

MW-42-030

MW-42-055 MW-27-085

MW-34-080

MW-42-065

MW-44-115MW-44-125

PE-01TW-03D

MW-34-100

0 500 1,000Feet

PG&E TOPOCK COMPRESSOR STATION, NEEDLES, CALIFORNIA

LEGEND

Groundwater Monitoring WellCompleted in Bedrock

Injection Well (Active)

Groundwater Monitoring Well

Test Well or Supply Well (inactive)

Extraction Well (Active)

California State Plane NAD83 Zone 5 US Feet

Notes:Bold/Italicized labels indicate sample collected using micropurge sampling method; otherwise, sample collected using the method indicated on Table 3-1.

FIGURE 1MONITORING WELL LOCATIONS ANDSAMPLING FREQUENCY FOR GMPWELLS IN PROPOSED SAMPLINGMETHOD TRIAL

Path: G:\PacificGasElectricCo\TopockProgram\GIS\MapFiles\2015\GMP_Report\Fig1_GMP_Sampling_Frequency_GMP.mxd Date Saved: 8/4/2015 4:06:35 PM

MW-70-105

MW-68-240MW-68-180

MW-67-260MW-67-225

MW-66-230MW-66-165

MW-65-225MW-65-160

MW-70BR-225

MW-69-195

MW-74-240

MW-68BR-280

MW-67-185

MW-66BR-270

PGE-07BR

PGE-8

MW-24BR

MW-12MW-24A

MW-24BMW-48

TW-01MW-38DMW-38S

MW-9

MW-10

MW-11

Inset A

Inset B

Sampling Frequency for Groundwater Monitoring Program (GMP)

Biennial samplingMW-17

MW-13 Annual sampling

Semiannual samplingMW-21

MW-9Annual; plus the next quarterly event following any channel-wide flows in Bat Cave Wash with discharge through the highway culverts

MW-38S Quarterly sampling

Monthly samplingTW-03D

Well with sampling method trialor change proposedTW-01

Colorado R

iver

INTERSTATE

BAT

CAV

E W

ASH

BN&SF RAILROAD

MW-20 Bench

Natural Trails Highway

WestMesa

EastMesa

500

600

550500

Bureau of Reclamation(Managed by BLM)

Parcel No. 650-151-06

Historic Route 66

Fort Mojave Indian Tribe

40

TreatmentPlant

CW-4

CW-3

CW-2

CW-1

OW-2

OW-1OW-5

IW-2

IW-3

0 350 700Feet

LEGEND

IM-3 Injection Well

Observation Well Cluster

Compliance Monitoring Well Cluster

Document Path: G:\PacificGasElectricCo\TopockProgram\GIS\MapFiles\2015\GMP_Report\Fig2_CMP_Sampling_Frequency_GMP.mxd

FIGURE 2MONITORING WELL LOCATIONS FOR CMPWELLS IN PROPOSED SAMPLING METHODTRIALPG&E TOPOCK COMPRESSOR STATION,NEEDLES, CALIFORNIA

1 inch = 350 feetCalifornia State Plane NAD83 Zone 5 US Feet

Well proposed for sampling method trialCW-4


Attachment 2 Logs for TW-04 and TW-05

Resistivity

---------------------------------- TW-04 Cased Well Geophysical Logs -----------------------------------

Med. Induction

Well Cluster MW-47 and TW-04

FIGURE SUMMARY OF HYDROGEOLOGIC LOGGING FOR TW-04 WELLIMPM WELL INSTALLATION REPORTPG&E TOPOCK COMPRESSOR STATIONNEEDLES, CALIFORNIA

GR

TW-04 Geophysical Log April 27, 2006

Log Units: Gamma Ray (GR, API units), Resistivity (ohm/m), Med. Induction ( mS/m)

0 ---------- Resistivity ------------ 20270

260

250

240

230

220

210

200

190

180

170

160

150

140

130

120

110

100

90

80

70

60

50

40

30

20

10

0

0 -------- Gamma Ray ----------- 100270

260

250

240

230

220

210

200

190

180

170

160

150

140

130

120

110

100

90

80

70

60

50

40

30

20

10

0

300 --------- Med. Induction ---------- 0270

260

250

240

230

220

210

200

190

180

170

160

150

140

130

120

110

100

90

80

70

60

50

40

30

20

10

0

Static Water Level

45

Static Water Level

MW-47-55

MW-47-115105

115

Qr3+Qrd

Qoa?

Toa0

2" PVC 4" PVC

Draft Privileged and Confidential

Tmc 267 ft bgs

55

210

250

TW-04

ES102007005BAO_Appendix_C_figures.indd_022708_lho

APPENDIX C-2ISUMMARY OF HYDROGEOLOGIC LOGGINGFOR TW-04 WELLRCRA FACILITY INVESTIGATION/REMEDIAL INVESTIGATION REPORT (VOLUME 2)PG&E TOPOCK COMPRESSOR STATIONNEEDLES, CALIFORNIA

Resistivity

---------------------------------- MW-50 Cased Well Geophysical Logs -----------------------------------

Med. Induction

Well Cluster MW-50

FIGURE ESUMMARY OF HYDROGEOLOGIC LOGGING FOR MW-50 WELLSIMPM WELL INSTALLATION REPORTPG&E TOPOCK COMPRESSOR STATIONNEEDLES, CALIFORNIA

GR

MW-50 Geophysical Log April 27, 2006

Log Units: Gamma Ray (GR, API units), Resistivity (ohm/m), Med. Induction ( mS/m)

0 ---------- Resistivity ------------ 20200

190

180

170

160

150

140

130

120

110

100

90

80

70

60

50

40

30

20

10

0

0 -------- Gamma Ray ----------- 100200

190

180

170

160

150

140

130

120

110

100

90

80

70

60

50

40

30

20

10

0

300 --------- Med. Induction ---------- 0200

190

180

170

160

150

140

130

120

110

100

90

80

70

60

50

40

30

20

10

0

Static Water Level

85

Static Water Level

MW-50-95

MW-50-200190

200

Qr

Toa1

2" PVC

Tmc 227 ft bgs

95

Toa0

TW-054" PVC

TW-05

110

150

ES102007005BAO_Appendix_C_figures.indd_022708_lho

APPENDIX C-2KSUMMARY OF HYDROGEOLOGIC LOGGINGFOR MW-50 WELLSRCRA FACILITY INVESTIGATION/REMEDIAL INVESTIGATION REPORT (VOLUME 2)PG&E TOPOCK COMPRESSOR STATIONNEEDLES, CALIFORNIA


Attachment 3 Logs for OW-5, CW-1, CW-2, CW-3, CW-4

OW-3D Core Log

RIL

---------------------------------- OW-3D Cased Well Geophysical Logs -----------------------------------

CIL

Observation Well Cluster OW-3

FIGURE B1-2

SUMMARY OF HYDROGEOLOGIC LOGGING

FOR OW-3 WELL CLUSTER

IM-3 GROUNDWATER INVESTIGATIONPG&E TOPOCK COMPRESSOR STATIONNEEDLES, CALIFORNIA

GR

Plots show percentages of coarse sediment (> No. 200 sieve) and gravel-size fragmentslogged in OW corehole.

Static Water Level

OW-3D Geophysical Log November 10, 2004

Log Units: Gamma Ray (GR, API units), Induction Resistivity (RIL, ohm/m), Induction Conductivity (CIL, uS/cm)

0 ---------- Resistivity ------------ 100 0 -------- Gamma Ray ----------- 150

250

200

150

100

50

0 --------- Conductivity ---------- 200

250

200

150

100

50

Static Water Level

centralizer

centralizer

centralizer

centralizer

86

116

180

200

242.5

262.5

272.510 ft sump

Static Water Level

0 100--% Coarse--

250

200

150

100

50

0 100--% Gravel--

no recovery

OW-3S

OW-3M

OW-3D

CW-1D Core Log

RIL

---------------------------------- CW-1D Cased Well Geophysical Logs -----------------------------------

CIL

Compliance Well Cluster CW-1

FIGURE B2-1


FOR CW-1 COMPLIANCE WELLS


GR


CW1 Geophysical Log March 2, 2005

Log Units: Gamma Ray (GR, API units), Resistivity (RIL, ohm/m), Conductivity (CIL, mS/cm)


250

200

150

100

50

0 --------- Conductivity ---------- 200300

250

200

150

100

50

Static Water Level

140

190

250

300

Static Water Level

0 100--% Coarse--300

250

200

150

100

50

0 100--% Gravel--

CW-1M

CW-1D

20' sump

centralizer

centralizer

centralizer

centralizer

CW-2D Core Log

RIL


CIL


FIGURE B2-2


FOR CW2 COMPLIANCE WELLS


GR


CW2-D Geophysical Log March 2, 2005

Log Units: Gamma Ray (GR, API units), Resistivity (RIL,ohm/m), Conductivity (CIL, mS/cm)


300

250

200

150

100

50

0 --------- Conductivity ---------- 200350

300

250

200

150

100

50

Static Water Level

152

202

285

335

Static Water Level

0 100--% Coarse--350

300

250

200

150

100

50

0 100--% Gravel--

CW-2M

CW-2D

centralizer

centralizer centralizer

centralizer

centralizercentralizer



centralizercentralizer

35520' sump

no recovery

CW-3D Core Log

RIL


CIL


FIGURE B2-3




GR



Log Units: Gamma Ray (GR, API units), Resistivity (RIL,ohm/m), Conductivity (CIL, mS/cm)


300

250

200

150

100

50

0 --------- Conductivity ---------- 200350

300

250

200

150

100

50

Static Water Level

172

222

270

320

Static Water Level

0 100--% Coarse--350

300

250

200

150

100

50

0 100--% Gravel--

CW-3M

CW-3D

20' sump

340

centralizer


centralizer

no recovery

no recovery

no recovery

CW-4D Core Log

RIL


CIL


FIGURE B2-4




GR



Log Units: Gamma Ray (GR, API units), Resistivity (RIL, ohm/m), Conductivity (CIL, mS/cm)


250

200

150

100

50

0 --------- Conductivity ---------- 200300

250

200

150

100

50

Static Water Level

120

170

233

283

Static Water Level

0 100--% Coarse--300

250

200

150

100

50

0 100--% Gravel--

CW-4M

CW-4D

20' sump

303








Attachment 4 Log for TW-01

0 5 10 15 20 25

280

260

240

220

200

180

160

25 20 15 10 5 0

Flow (gpm)

Dynamic Test #1 (Top)

Flow (gpm)

Dynamic Test #2 (Bottom)

0 5 10

Pump at Top

280

260

240

220

200

180

160

10 5 0

Pump at Bottom

Incremental Flow (gpm)

0

50

100

150

200

250

300D

ep

th(f

ee

tbg

s)

SW

SM

SC

ML

MH

CL

CH

OL

OHGP

GW

Lithology Legend

GM

GC

SP

Water Table

UNSATURATED

ALLUVIUM

SATURATED

ALLUVIAL AQUIFER

BEDROCK

Cemented Red Fanglomerate

Alluvium

LITHOLOGY & WELL COMPLETIONGEOPHYSICAL LOGS VELOCITY LOG

184004.PS.02_E092003003SFO_GW Test Well TW-1_11/19/03_ccc

Older

AlluviumYounger

TW-1 WELL COMPLETION SHOWINGGEOPHYSICAL LOGS, VELOCITY LOGSAND LITHOLOGYEXPLORATORY DRILLING RESULTSPG&E TOPOCK


Attachment 5 MW-58BR and MW-64BR Construction

History

MW-58BR Sampling ConfigurationsPG&E Topock Compressor StationNeedles, California

NOTES:– Scale is approximate.– All depths presented as feet below ground surface.

META

DIOR

ITE

BED

ROCK

UNCO

NSOL

IDAT

EDLI

THOL

OGY

0

50

100

150

200

OPEN BOREHOLE(SHALLOW)

TD = 115'

OPEN BOREHOLE(DEEPER)

TD = 206'

FLUTE(UPPER AND

LOWER ZONES)

95'

115'

160'

TD = 206'

LEGEND

Portion of borehole exposed during sample collection

Portion of borehole sealed during sample collection

PACKER– SHALLOW SET (UPPER AND

LOWER ZONES)

PACKER– DEEP SET

(UPPER AND LOWER ZONES)

TD = 206'

~113'~117'

APPROXIMATEDEPTH TO WATER

66'

LOWER ZONE

LOWER ZONE

UPPER ZONE

UPPER ZONE

LOWER ZONE

UPPER ZONE

TD = 206'

~158'~162'

ES100510163544BAO_MW-58BR-Samp_Config.ai 05-24-13 dash

MW-64BR Sampling ConfigurationsPG&E Topock Compressor StationNeedles, California

NOTES:– Scale is approximate.– All depths presented as feet below ground surface.

LEGEND

Portion of borehole exposed during sample collection

Portion of borehole sealed during sample collection

ES100510163544BAO_MW-64BR-Samp_Config.ai 05-24-13 dash

META

DIOR

ITE

BED

ROCK

LITH

OLOG

Y

0

50

100

150

200

250

OPEN BOREHOLE

FLUTE(UPPER,

MIDDLE, AND LOWER ZONES)

150'

175'

205'

230'

TD = 260'TD = 260'

APPROXIMATEDEPTH TO WATER

120'

PACKER(UPPER AND

LOWER ZONES)

TD = 260'

~148'~152'

MIDDLE ZONE

LOWER ZONE

UPPER ZONE

LOWER ZONE

UPPER ZONE

Documents

Response to CSLC Letter 071017 - dtsc-topock.com · Well ID Recommendation in August 2015 Letter Approval Conditions or Requests in DTSC’s April 6, 2017 Letter PG&E’s Reply, July