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East Branch Dam Safety Initiative

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 click here to email us. We will run down the rumor and get back to you with the truth within 48 hours. Ask us, we'll tell you.

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DATE OF QUESTION   QUESTION RESPONSE 
 05/01/2017 We hear that the contract has been extended, is this true?   The Army Corps has extended the grouting program currently underway to ensure proper treatment of the foundation rock in preparation for installation of a full-depth seepage cutoff wall. The wall will consist of a minimum 18-inch-wide continuous vertical concrete cutoff wall approximately 2,300 feet long with an approximate maximum depth of 250 feet through the existing embankment dam into bedrock. Completion of the cutoff wall and follow on verification of the repair will allow the Corps to operate the dam at full capacity and restore the reservoir to its regular water levels. The additional work is expected to extend the dam safety project for an additional 7 months. The most recent estimated completion date of the seepage cutoff wall construction is early 2020. The Army Corps and the contractor are working to identify and implement efficiencies in sequencing of the work that will reduce the construction schedule.
 05/01/2017 Is it true that the contractor is demobilizing?  Project subcontractors demobilize as they complete their individual contract fulfillment. However the primary contractor is not demobilizing and continues to manage the project. 
  Recently, we have had many questions from concerned citizens about the historically low lake levels at East Branch Clarion River Lake. Our water management section provides the following information in response. You may also Like our Facebook site and view a video update from our Water Management Section.  

Currently, East Branch Dam Lake pool has been low. This year, the lake reached its highest pool on May 30, and since then there has been only seven days that the inflow has been greater or equal to the outflow. Every other day, the district has had to draw from the lake storage to meet its downstream flow requirement at Johnsonburg. When comparing East Branch to other lakes in the area, the Allegheny Reservoir is also low, however, it will likely reach winter pool several weeks ahead of schedule due to a lack of inflow needed to meet its downstream flow schedule. Tionesta Lake is not low because it does not have a downstream flow requirement. Other smaller non-Corps lakes in the area may still have their pool levels if recreation is their primary mission and do not have downstream flow targets to maintain.

 
   QUESTION RESPONSE 
  The contractor is drilling holes into the existing dam and filling them with grout. There is an area of seepage near the base of the dam where a "bus sized void" is present. I would like to know when core drilling into this void / seepage area is scheduled to take place.  I believe you're referring to the void that was detected in 1957 after muddy flows were observed downstream of the dam. Engineers at the time investigated the situation as it could have been an indication of internal erosion and a serious condition that could lead to dam failure if unaddressed. A 'bus-sized void" was detected at the time and an aggressive grouting effort was undertaken to fill the void and address any other areas in question.  

Based upon on a risk assessment in 2009, USACE determined this dam to be a high risk dam primarily due to the risks associated with re-initiation of internal erosion at or near an embankment void grouted during a 1957 internal erosion event. It was determined that the unknown condition of that repair and the potential for similar seepage events required the implementation of a dam safety initiative that in part required additional grouting and the installation of a cutoff wall through the earthen dam. Since early this year, the government's contractor has been drilling and grouting the rock underneath the dam to fill any voids and fissures in the rock prior to installation of the cutoff wall. The grouting work is ongoing at this time, including critical areas such as the previously repaired site. 

If you want to learn more about the East Branch Dam Safety Initiative, please visit http://www.lrp.usace.army.mil/Missions/Planning-Programs-Project-Management/Key-Projects/East-Branch-Dam-Repair/ and/or feel free to contact our office at any time if you have additional questions.
  QUESTION   
  I just heard today that work has been suspended on this project. I would like to know if this is true and, if so, why?  No, work has not been suspended. 
  QUESTION   
  I'm hearing that construction contract is shutting down.  Is there any truth to that?   Bencor our construction contractor is not shutting down.  Drilling and grouting work continues this summer across the dam in the embankment and foundation.  Once the grouting is satisfactorily completed the contractor is required to complete demonstration sections of the cutoff wall.   Once the cutoff wall demonstrations are satisfactorily completed then the remainder of the cutoff wall can be completed. 
  QUESTION RESPONSE
  Any truth to the QUESTION that the repair would take several years to finish?

 

Yes, the proposed repair will take several years to design and build; if all goes as currently planned, especially receiving appropriate funding, we project a completion date of 2018. This is an optimal estimate, potentially impacted by many variables including: funding, selected repair plan, weather.

 

  QUESTION RESPONSE
  Would it require the draining of the lake?

 

No. Constructing the cut-off wall is not expected to reqire draining the lake.

  QUESTION RESPONSE
  When will we know the status of the lake?

 

The next public meeting is scheduled for April 11, 2013 at 7 p.m. at Johnsonburg High School. An updated dam safety status report will be added to the East Branch home page and dam safety page.

 

  QUESTION RESPONSE
  Does it need repair and if so, when will the repairs take place?

 

The repair of the dam was approved in Oct. 2010. An internal cut-off wall has been approved to repair the dam. Construction could start as early as fall 2013. 

  QUESTION RESPONSE
  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.

 

  QUESTION RESPONSE
 

Is kayaking permitted on East Branch Lake?

Yes, kayaking is allowed on the lake. Also, both the federal and the state Instanter boat launches are open for hand- and trailer-carried boats. The launch fees for have been waived.

 

 

  QUESTION RESPONSE
 

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

 

  QUESTION RESPONSE
  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.

 

  QUESTION RESPONSE
 

Is the lake closed?

No. The lake is not currently closed; however, in the interest of public safety, the campground and picnic area will be closed starting in 2014 through completion of construction. 

  QUESTION RESPONSE
 

Is East Branch Dam about to fail?

Public safety is the number one priority of the Corps' Dam Safety Program. Our screening process at East Branch Dam identified confirmed seepage-related issues. 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.

 
  QUESTION RESPONSE
 

Is the Corps planning on draining the lake?

The Corps reviews it decision on operating the reservoir pool at least annually. The Corps will continue to operate the reservoir pool level consistent with the approved interim water control plan unless the condition of the dam changes. No further changes in reservoir operations are anticipated at this time.

  QUESTION RESPONSE
 

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.