Attach. 27, 2012-01-25 Russell to Waugh email

From: Herrick, Dayna J <[e-mail]>
Sent: Wednesday, January 25, 2012 12:31 PM
To: Mitchell, David F <David.Mitchell (duke-energy.com>
Subject: FW: Buck Station - New Dam — Additional Primary Basin (Rowan -068)
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From: Russell, Tim
Sent: Wednesday, January 25, 2012 11:17 AM
To: Waugh, Dave; Herrick, Dayna J; Zalme, Nob J; Pratt, Bobby
Cc: Townsend, Steve; Shuping, Todd; Niehaus, Robert A; Landseidel, Mark E; Brooks, David M Jr; Papp, Alex S
Subject: RE: Buck Station - New Dam — Additional Primary Basin (Rowan -068)
Folks,
Bobby Pratt and I had a telephone conversation with Andy Schneider, NCDENR's Assistant Dam Safety Engineer.
Andy indicated that he and Steve McEvoy (NCDENR's Dam Safety Engineer) would have preferred the gate
excavation adjacent to the additional primary basin dam to have been properly engineered and permitted prior
to executing the work. Since we were able to provide the S&ME engineering report that indicates acceptable
factors of safety against slope failure, Andy indicated there would not be any repercussions for the unpermitted
work. To alleviate some concern expressed by Andy about the relatively steep excavation slope, we indicated
large sized rip rap overlying a separation geotextile would be installed on the excavation slope face as soon as
possible as an interim measure to help protect against erosion and shallow sloughing. Additionally, Andy
indicated that any additional work would need to be addressed via engineered documents and submitted in a
permit request application to Dam Safety for approval. Andy recognized the urgency of this situation, and he
indicated an expedited two-week review turn -a -round time can be expected. This is the best possible outcome.
Their forgiveness of the unpermitted work and willingness to expedite the review process are a result of the
good relationship we've established with Dam Safety, and I hope to maintain that relationship going forward.
So, thanks in advance for everyone's participation in supporting me in that effort.
Going forward, I believe Bobby is working on arranging a meeting with Shaw, S&ME, and Sells to discuss the
tasks associated with this issue and Duke's expectations.
Tim Russell, P.E.
Senior Engineer
Program Engineering
Generation Engineering
Duke Energy
526 South Church Street
Charlotte, NC 28202
[phone] - Office
[phone] - Mobile
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From: Russell, Tim
Sent: Wednesday, January 25, 2012 8:02 AM
To: Waugh, Dave; Waugh, Dave; Zalme, Nob J; Pratt, Bobby
Cc: Townsend, Steve; Shuping, Todd; Niehaus, Robert A; Landseidel, Mark E; Brooks, David M Jr; Papp, Alex S
Subject: FW: Buck Station - New Dam — Additional Primary Basin (Rowan -068)
Duke -SEA -heck -00585479

Folks,
Below is email correspondence I've exchanged with Dam Safety with regard to the gate excavation performed
by Shaw near the toe of the additional primary basin dam at Buck Station. I will provide an update subsequent
to the meeting with Dam Safety to summarize the results of the discussion. If there's anyone I've missed on this
email distribution, let me know so that I can include them on the summary email. Thanks.
Tim Russell, P.E.
Senior Engineer
Program Engineering
Generation Engineering
Duke Energy
526 South Church Street
Charlotte, NC 28202
[phone] - Office
[phone] - Mobile
From: Russell, Tim
Sent: Wednesday, January 25, 2012 7:50 AM
To: 'McEvoy, Steve'; Schneider, Andrew
Subject: RE: Buck Station - New Dam — Additional Primary Basin (Rowan -068)
Andy and Steve,
Attached is S&ME's stability analysis letter dated January 24, 2012 addressing the gate excavation at Buck
Station. In short, I've itemized the highlights in the list below:
• The existing embankment dam (New Dam of the Additional Primary Basin) was excavated near the toe
and appears to be inclined near 1(H):1(V) with a height of approximately 5 ft.
• A factor of safety for the downstream embankment (along the analysis section) was approximately 2
(2.06) for large (global) failure surfaces extending from near the dike crest to just beneath the gate
excavation area and exiting near the existing dike toe/roadway ditch.
• A factor of safety of approximately 1.7 (1.68) is obtained from an arc extending through the toe of the
gate excavation to near the inside corner of the first (lower) dike bench.
• By comparison, a similar profile section evaluated prior to the gate excavation exhibited a factors of
safety near 2 (2.07) for global stability and near 2.3 (2.28) for local stability of the south road excavation
slope.
• The factors of safety are considered acceptable for embankment stability for the static condition
evaluated, but the gate excavation sloped at near 1(H): 1(V) will need to be addressed to prevent long
term erosion and sloughing issues.
Tim Russell, P.E.
Senior Engineer
Program Engineering
Generation Engineering
Duke Energy
526 South Church Street
Charlotte, NC 28202
[phone] - Office
[phone] - Mobile
From: McEvoy, Steve [mailto:[e-mail]]
Sent: Tuesday, January 24, 2012 4:37 PM
To: Schneider, Andrew
Cc: Russell, Tim
Subject: FW: Buck Station - New Dam — Additional Primary Basin (Rowan -068)
Duke -SEA -heck -00585480

Andy:
Please review and advise me on this. We'll then schedule a meeting with Tim. Thanks
Steven M. McEvoy, PE
State Dam Safety Engineer
NC Land Quality Section
1612 Mail Service Center
Raleigh, NC 27699-1612
Office: [phone] ext. 711
[e-mail]
E-mail correspondence to and from this address may be subject to the North Carolina Public Records Law and
may be disclosed to third parties.
From: Russell, Tim [mailto:[e-mail]]
Sent: Tuesday, January 24, 2012 2:46 PM
To: McEvoy, Steve
Cc: Schneider, Andrew
Subject: Buck Station - New Dam — Additional Primary Basin (Rowan -068)
Steve,
As you know, Shaw is constructing a new combined cycle gas power plant downstream of the additional primary
basin at Buck Station. Apparently, Shaw has excavated adjacent to the downstream side of the dam toe to
install a security gate and transformer pad. The current extent of the gate excavation does not extend to within
the footprint of the dam. However, it would appear that the excavation completed for the gate could
potentially affect the local stability of the toe. I have attached four PDF files for your reference. File BUK00-CV-
C-GR.PL-50-1.pdf depicts the location of the gate and the planned gate excavation contours. File BUKOC-CV-C-
GR.PL-04-2.pdf is a larger view of this area to better depict the gate location relative to the dam. File 3039-d-
02.pdf is the original design drawing of the dam. File IMG_3686.pdf is a picture of the excavation.
Shaw engaged S&ME to perform a stability analysis. The final stability report should be complete sometime this
week, but conversations with Larry Armstrong (S&ME's design engineer for the repair recently completed at
Allen) indicate the analyses are complete and the results indicate a global factor of safety of greater than 2 for
the critical slip surface under steady-state conditions. The local factor of safety for the toe is reportedly 1.7 for
the critical slip surface (again) for the steady-state condition. As such, there does not appear to be any stability
related issue.
Additional work is proposed and will likely include re-routing the ditch line around the transformer pad, altering
(turning) the 30 -inch CMP to redirect surface water, and flattening the excavation slope. Currently, Shaw's
surveyor and civil designer are in the process of developing a topographic plan of the affected area and
calculating channel flows for sizing conduit. Once that is complete, I understand there will be a meeting
between Duke, Shaw & S&ME to discuss the path forward (see attached email). Before that meeting, I'd like to
talk with you and Andy about how the project should proceed and what you expect from a permitting
standpoint. Let me know when your schedule allows a good time to discuss this issue. Time is of the essence, so
thanks in advance for your immediate attention and assistance.
Tim Russell, P.E.
Duke -SEA -heck -00585481

Senior Engineer
Program Engineering
Generation Engineering
Duke Energy
526 South Church Street
Charlotte, NC 28202
[phone] - Office
[phone] - Mobile
Duke -SEA -heck -00585482