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.

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.

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.

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.