PITTSBURGH DISTRICT

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. 

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.

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

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. 

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.

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.

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

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.

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. 

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.

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.

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.