From: KENT Mavis D

Sent: Wed Mar 11 12:25:56 2009

To: 'Sarah Prowell'

Cc: 'Chris Kimmel '

Subject: RE: Proposed Lower TSA Monitoring Reductions

Importance: Normal

Thanks for the explanation of sampling. Since the purpose of the pilot shutdown of EW-12 was for the goal of no more extraction from that well I would agree with removing the pump.

From: Sarah Prowell [mailto:sprowell@ix.netcom.com]

Sent: Wednesday, March 11, 2009 11:40 AM

To: KENT Mavis D

Cc: 'Chris Kimmel '

Subject: RE: Proposed Lower TSA Monitoring Reductions

Thank you, Mavis. It’s much appreciated. Regarding your question of sampling method:

BOP-69(usg) and EW-5 have been sampled using diffusion bags, as they are “monitoring” wells (with no pumps). Because the EW-5 well screen is >20 feet in length, two diffusion bags (Upper and Lower) have/are sampled in this well.

MW-14R(ds) has insufficient water to qualify for diffusion bag sampling (i.e., generally less than 5 feet of water within the screened interval), so it is sampled using conventional purge methods.

While EW-12 is not pumping, the pump assembly is still in the well since it is not yet approved for final discontinuation of pumping. Once it is approved for final pump removal, we plan to install 2 diffusion bags in this well (Upper and Lower), since the screen is longer than 20 feet. ---Is it acceptable to DEQ to final discontinue pumping in EW-12, for permanent pump removal and conversion of this well to monitoring status? If so, we’ll remove the pump assembly and begin sampling with two diffusion bags.

Because EW-16, EW-18, and EW-23 are actively pumping, the samples are “grab” samples from the well sampling ports. (Although EW-18 pumps every other two months, the pump assembly remains in the well and thus, the wellhead is not accessible for diffusion bag lowering/installation and sampling. [A steel cap is bolted to the well head, from which the pump assembly hangs. There is no “port” of adequate size to lower the diffusion bags into the well for sampling during pump off cycles.])

From: KENT Mavis D [mailto:KENT.Mavis@deq.state.or.us]

Sent: Wednesday, March 11, 2009 11:26 AM

To: Sarah Prowell

Cc: Chris Kimmel

Subject: RE: Proposed Lower TSA Monitoring Reductions

I have reviewed your monitoring reduction proposals in the emails below and the attachment tables and map.

I approve changes to BOP-69usg monitoring and would go with the “or” to discontinue all monitoring based on the decision criteria, even though it has not yet been two years since concentrations went below the MCL since it is very close in time. Based on the decision process, you would sample this well in 2 years and if the concentrations are still below the MCL you could request abandonment.

I approve reducing monitoring of EW-5 from semi-annual to annual but would favor sampling in winter as that seems to be the highest concentrations measured.

I approve reducing sampling of EW-12 from quarterly to semi-annual.

I approve reducing sampling of EW-16 and EW-23 from quarterly to semi-annual.

I approve reducing sampling of EW-18 and MW-14Rdg from every other month to quarterly.

Let me know if there are other issues. Were all these wells (non-pumping) sampled with diffusion bags?

From: Sarah Prowell [mailto:sprowell@ix.netcom.com]

Sent: Wednesday, March 11, 2009 9:18 AM

To: KENT Mavis D

Cc: Chris Kimmel

Subject: Proposed Lower TSA Monitoring Reductions

Hello Mavis,

Could you let us know if you approve the following proposed TSA monitoring changes? The email stream below includes Chris Kimmel’s response comments to the proposed changes sent to her for review. So we now seek your review and approval.

Thanks. Let us know what you think. –Sarah

P.S. (VOC data for each well is attached, along with a TSA Well Location Map [i.e., the 8 ½ x 11 quarterly report figure]).

From: Chris Kimmel [mailto:CKimmel@landauinc.com]

Sent: Wednesday, March 11, 2009 9:02 AM

To: Sarah Prowell

Subject: RE: Lower TSA Monitoring Reductions - For Your Comment

Hello Sarah, please see comments below

Christine Kimmel

Senior Geologist

Landau Associates Inc.

130 2nd Ave South

Edmonds, WA 98020

(425) 778-0907

From: Sarah Prowell [mailto:sprowell@ix.netcom.com]

Sent: Tuesday, March 10, 2009 5:42 PM

To: Chris Kimmel

Subject: Lower TSA Monitoring Reductions - For Your Comment

Hello Chris,

I wonder if you might have any comments for the following Lower TSA monitoring reductions? I’d like to email recommendations this week or next to Mavis, to keep streamlining where and when we can. Let me know what you think. Thank you. -Sarah

BOP-69(usg) –

• * Reduce from semiannual to annual, based on declining concentrations for at least 2 years.

• * àOr, discontinue all monitoring, since this CU2 equivalent well is outside the plume limits, there are other nearby Lower TSA wells more suitable for long term monitoring (i.e., BOP-23 (dg) to the south and BOP-44(dg) to the north), and TCE concentrations have been steadily declining since NTS pilot shutdown began in June 2006. TCE concentrations have been below MCL for 1.5 yrs, well is located outside plume and location duplicates other nearby wells. I would support the recommendations to remove the well from the monitoring program for 2 yrs then conducting verification sampling prior to proposal for abandonment (if verification samples are below MCL).

The following criteria for discontinued monitoring (presented under Section A-2 of the Annual Rpt) seem consistent:

• * The well is located outside the limits of the plume and is no longer needed to monitor hydraulic plume control or restoration progress
• * The location of a well duplicates another well better suited to evaluate hydraulic control and restoration progress.

EW-5, EW-12, EW-16, and EW-23 –

• * Reduce sampling frequencies, due to stable to declining concentrations that have occurred in each well for more than two years.
  • * EW-5 was pilot shutdown in 2003 and is now a monitoring well; it has remained consistently below the MCL for more than 2 years, per reduction criteria. Approve reduced monitoring from semiannual to annual.
  • * EW-12 was pilot shutdown in Dec. 2007, since its capture area duplicated capture by EW-23. TCE concentrations have been stable to slightly declining for the last 2 years (TCE = 5.1 in Feb. 09). Quarterly sampling seems more than is needed under stable to declining conditions, so a reduction to semiannual is proposed. Agree that quarterly sampling to too much and that semiannual sampling is more appropriate given the stable conditions and the active operation of EW-23.
  • * EW-16 and EW-23 are actively operating and have either non-detectable to very low TCE concentrations since monitoring began in each of the wells. Quarterly monitoring seems more than is needed and semiannual sampling is recommended. Agree that quarterly sampling is too much given the low concentrations and semiannual seems more appropriate.

EW-18 and MW-14R(dg) -

• * These wells have been sampled every 2 months since EW-18 pulse pumping began January 08. Concentrations have remained stable in EW-18 and declined notably in MW-14R(dg) since pulse pump operation began; thus a reduction to quarterly sampling seems adequate for continued trend evaluation. Agree.

Sarah Prowell, R.G.

Prowell Environmental, Inc.

2216 SW Sunset Blvd.

Portland, OR 97239

Phone: 503/452-0972

Fax: 503/452-1427

Email: sprowell@ix.netcom.com