Safety Initiative Home
East Branch Lake Home
Water Equivalents
|
ASK US, WE’LL TELL YOU -- The Rumor Control Button is here
for your benefit. If you have heard or read something about East
Branch Dam and want to check whether it is true or just a rumor,
please
email
East Branch Dam Rumor Control. We will run down the
rumor and get back to you with the truth within 48 hours. Ask
us, we’ll tell you.
RUMOR |
FACT |
When will we know the status of the
lake? |
We must
investigate many unknowns before we can know what
our actions will be and how long those actions will
take. We have completed an initial investigation
which supports our decision to implement interim
risk reduction measures to include lowering the
reservoir. With these measures, we are able to
operate the dam safely. We will start a new phase of
the investigation this fall by drilling for soil
samples to check the possible seepage paths
indicated by an electro-magnetic scan of the dam and
to gather data needed to design a repair. We expect
drilling to be completed in early 2009. We need to
analyze that data before determining a fix for the
dam.
|
RUMOR |
FACT |
Does it need repair and if so , when
will the repairs take place? |
We do
believe at this point that some type of repair will
be necessary. At earliest and with efficient
funding, we could see construction begin in 2010.
The duration of the construction project is
determined by what we find through our investigation
and the nature of the repair.
|
RUMOR |
FACT |
I have heard that the dam needs to
be drained for safety issues, but you are not doing
so because of pressure from the Domtar Mill.
|
The
decision to lower the reservoir, and to what level
was based solely on public safety. Dam safety
professionals within the Corps of Engineers
determined that implementation of specific risk
reduction measures, including our current pool
restriction, would allow safe operation of the dam
while investigations are undertaken at the site. We
are working closely with the Domtar Mill, DCNR, PA
Fish & Boat Commission and other stakeholders to
ensure we reduce the impacts of this necessary dam
safety investigation; however, life safety is our
number one priority and will be paramount in
directing our current and future actions.
|
RUMOR |
FACT |
Is kayaking permitted on East Branch
Lake? |
Yes. The boat launch and lake are
still open to hand-carried vessels, however the
launch is closed trailer-hauled vessels.
|
RUMOR |
FACT |
How much water is there? |
The amount of water in East Branch
Lake varies through the year. The amount of water in
a lake or reservoir is usually measured in
acre-feet. One acre-foot is enough water to cover an
acre of land one foot deep. At the historic normal
summer pool, elevation 1670, East Branch Lake
contained 64,000 acre-feet of water. As currently
operated the lake contains 44,000 acre-feet of water
at the interim summer pool, elevation 1650. The
amount of water will drop to about 15,000 acre-feet
by late fall. (For perspective, one acre-foot of
water is equivalent to 325,900 gallons.)
For water
level equivalents, visit:
http://www.irwd.com/MediaInfo/water_equivalents.php
|
RUMOR |
FACT |
If the dam were to break, how long
would it take for Wilcox, Johnsonburg and Ridgway to
be flooded. Even though you say it won't
break, how long do you estimate that we, living in
Ridgway would have before it hit us? |
To be
most cautious in emergency planning, we base our
calculations on the worst case scenario of the lake
being completely filled and a rapidly occurring
breach in the dam. In reality, conditions are very
unlikely to be so extreme. In over fifty years of
operation, the East Branch Lake has yet to be filled
to capacity. Even during the record Hurricane Agnes
event in 1972 the lake level was over 12 feet below
maximum pool and twenty-one feet below the top of
the dam. In addition, the dam is inspected and
monitored closely for advance indications of
developing problems. During a serious
seepage-related incident in 1957, observation of
unusual seepage conditions allowed ample time to
take action to prevent a failure.
Based on
our emergency action plan reflecting the worst case
scenario, Johnsonburg, seven miles downstream of the
dam, would see the first flood water arrive two
hours after a breach. The peak flood would occur 30
minutes later. At Ridgway, 15 miles downstream of
the dam, the first flood water would arrive three
hours after a breach, and the peak flood would occur
in three hours and 30 minutes. The town of Wilcox is
not in the path of flooding because it is located
well upstream in the valley of the West Branch, a
different fork of the Clarion River.
|
RUMOR |
FACT |
Is the lake closed? |
No. The lake is not closed. The
state and federal boat launches are closed due to
the low water level. |
RUMOR |
FACT |
Is East Branch Dam about to fail? |
No.
Public safety is the number one priority of the
Corps' Dam Safety Program. Our screening process at
East Branch Dam identified confirmed and unconfirmed
seepage-related issues which merit further analysis
and evaluation. To reduce the risk to the public,
Pittsburgh District implemented several interim risk
reduction measures, including increased monitoring;
24/7 staffing; updated emergency action plans; and
reduced water levels in the reservoir to relieve
pressure on the dam. These and other short-term
actions allow us to operate the dam to meet our
public safety objective while we further investigate
our concerns and pursue long-term repairs, if
necessary.
|
RUMOR |
FACT |
Is the Corps planning on draining
the lake? |
No. The Corps will
continue to operate the reservoir pool level
consistent with the approved interim water control
plan. No further changes in reservoir operations are
anticipated at this time. |
RUMOR |
FACT |
If the dam is unsafe, why isn't the
Corps draining the lake? |
The Corps has implemented risk
reduction measures to ensure we are operating the
dam to our safety standards. Public safety is our
number one priority. Our preliminary investigations
support our decision to operate the reservoir under
the current interim water control plan. |
|