From: KENT Mavis D

Sent: Thu Nov 29 11:52:25 2007

To: 'Sarah Prowell'

Cc: Chris Kimmel

Subject: RE: Request for 3-Week EW-22 Shutdown and Diffusion Bag Sampling

Importance: Normal

Yes, I think the sampling will provide good information and not jepardize overall plume control. I will be out of the office next week and will return on Monday December 10th. If you have other items you want approval for, could you include documentation for the EW-22 and BOP-22(ds) in that summary? Thanks.

Mavis D. Kent

Cleanup & Emergency Response Section

DEQ Northwest Region - East Side Office

1550 NW Eastman Parkway, Suite 290

Gresham, Oregon 97030

503-667-8414 X55008

503-674-5148 Fax

kent.mavis.d@deq.state.or.us

-----Original Message-----

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

Sent: Thursday, November 29, 2007 11:06 AM

To: KENT Mavis D

Cc: Chris Kimmel

Subject: Request for 3-Week EW-22 Shutdown and Diffusion Bag Sampling

Hello Mavis,

We would like to ask DEQ’s permission to temporarily shut Upper TSA extraction well EW-22 off for 3 weeks to allow multiple diffusion bag sampling of that 40-foot long well screen interval. The data will help us characterize the eastern extent of the Upper TSA plume. Concurrently, we would also like to also place multiple diffusion bags in BOP-22(ds) to evaluate whether there may be correlations in TCE vertical distribution at these 2 locations.

While hydraulic control of the BOP-22(ds) plume would be temporarily suspended during the 3-week EW-22 shutdown, once EW-22 pumping resumes it will recapture groundwater, for a “net-sum” hydraulic containment of the plume.

If acceptable to DEQ, we anticipate shutdown on December 3 (next Monday); diffusion bag installations on December 7 (Friday), and sample collection on December 21. EW-22 would resume pumping as soon as possible after the samples are collected.

Could you let us know if you approve these actions? Thank you. –Sarah

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