NC0003425_Exhibit 12_20170101

EXHIBIT 12
Notice of Inspection - Dam Safety Law
Lake Hyco Dam
June 10, 2010

' LF A. WAA
NCDENR
North Carolina Department of Environment and Natural Resources
Division of Land Resources
James D. Simons, PG, PE Land Quality Section Beverly Eaves Perdue, Governor
Director and State Geologist Dee Freeman, Secretary
June 10, 2010
NOTICE OF INSPECTION
DAM SAFETY LAW
Mr. Fred Holt
Progress Energy Carolinas, Inc.
Environmental, Health and Safety Services Section
PO Box 1551 PEB 4
Raleigh, NC 27602
RE: Lake Hyco Dam
State ID: PERSO-002
Person County
Watershed: Roanoke
Dear Mr. Holt:
Pursuant to the North Carolina Dam Safety Law of 1967, on February 24 and March 8, 2010, personnel of the Land Quality
Section performed a periodic inspection of the subject high hazard potential dam, which is located on the Hyco River in Person
County. The Dam Safety Law of 1967 provides for the certification and inspection of dams in the interest of public health,
safety, and welfare. Our goal is to reduce the risk of failure of such dams, to prevent injuries to persons, damage to property,
and to ensure the maintenance of stream flows.
According to the above mentioned visual inspections, the dam appears to be in a stable condition at this time. However, we
recommend the following items pertinent to maintenance and operation of the dam:.
(1) Continue to remove all trees and thick undergrowth from the embankment and immediate surrounding area. This will serve
to (a) prevent the formation of a root system which might significantly increase seepage through the dam which could ultimately
result in failure of the structure, (b) reduce the possibility of damage to the dam due to the uprooting of trees by wind or other
natural causes, and (c) facilitate inspection and increase the likelihood of early detection of more serious problems connected
with the dam. This is particularly important along the abutment contacts where seepage has been observed.
(2)Maintain a ground cover sufficient to restrain accelerated erosion on all earthen portions of the structure. This will enhance
the stability of the dam should these portions become exposed to overflow or other forms of concentrated flow. This particularly
applies where erosion was observed at the abutment contacts. As discussed with Progress Energy personnel during our visit, it is
recommended that you work to achieve a predominantly turf grass cover. Weeping lovegrass and serecia lespedeza should be
taken out of the seed mixes used; appropriate clover and Korean or Kobe lespedeza should be added if legume is desired. The
recently proposed SlopeMaster specifications for use at the Cape Fear Plant are considered an acceptable alternative.
Raleigh Regional Office
1628 Mail Service Center, Raleigh, North Carolina 27699-1628 • Phone: [phone] / FAX: [phone]
3800 Barrett Drive, Raleigh, North Carolina, 27699

Notice of Inspection
PERSO-002
June 10, 2010
Page 2 of 2
(3) Periodically monitor the dam and appurtenant works with respect to elements affecting their safety. This is in light of the
legal duties, obligations, and liabilities arising from the ownership and/or operation of a dam. This particularly applies to the
previously described erosion and evidence of seepage observed as well as the condition of the concrete spillway. Your current
inspection program, including periodic reviews by your independent consultant, is an appropriate way to address this
recommendation.
Two of the more common types of earth dam failures are caused or influenced by excessive seepage. Excessive seepage can
produce progressive internal erosion of soil from the downstream slope of the dam or foundation toward the upstream side to
form an open conduit or "pipe". Seepage pressures decrease the strength characteristics of the embankment soil. The resulting
reduction in the embankment stability can produce a slide failure of the downstream slope. Please monitor the dam for any
changes of this nature.
As a dam owner, you may incur liability should your dam have a problem or fail, if such an event results in loss of life,
property damage, or environmental damage downstream. It is therefore requested that you prepare an Emergency Action
Plan (EAP) for this dam. The EAP establishes procedures to be followed in events that could adversely impact the dam
such as extreme precipitation, seismic activity, excessive seepage, slides, sinkholes, and other natural hazards, and for
warning the public downstream in the event of an emergency at the dam. Guidance for preparing an EAP can be found on
the Internet at http:Hwww.dIr.enr.state.nc.us/pages/damsafetyprogram.htmI or by calling Dam Safety Program staff at (919)
733-4574. Two copies of an EAP for this dam should be submitted to the following address:
NC Division of Land Resources
Land Quality Section
Attn: Mr. Steven M. McEvoy, PE
1612 Mail Service Center
Raleigh, NC 27699-1612
Although the inspections by our staff are relatively infrequent and offer no safety guarantees, we hope that you will use the
information provided in this letter as you fulfill your obligation to safely maintain and operate your dam. In order to help us
keep our records up-to-date and therefore serve you better, please notify us concerning any changes in address or ownership.
Your cooperation in this effort is greatly appreciated.
If there are any questions or if we can be of any assistance, please do not hesitate to contact me at [phone].
Sincerely,
q
?Engineer
Jr., PE, C SC
ction
Raleigh Regional Office
cc: State Dam Safety Engineer
File