Pictured above – A sample of one type of Aquabarrier “cofferdam”
Beaver Dam Reconstruction Update
The official Public Hearing on the proposed Beaver Dam Reconstruction project, estimated cost at a maximum $5 million, was held this Tuesday night at the Orange County Government Center. Few people attended and only one spoke. Nancy Calhoun, a former Supervisor of Blooming Grove, spoke in favor of proceeding with the project, saying it has been needed for a long time.
After making several unsuccessful attempts to get answers from the NYS DEC about the possible danger of disturbing PFO’s in sediment at the northwest end of the lake, the Orange County Post spoke to Commissioner of Public Works, Eric Denega, about precautions that may be taken to prevent any PFO’s in the sediment from travelling through the lake and into the Moodna Creek when the lake is emptied, a process which is expected to be done at the beginning of the project.
Sediment at the end of the lake closest to Stewart International Airport was tested in 2016 and came up with readings even higher than those that impacted Washington Lake, causing a State of Emergency for City of Newburgh drinking water. Their PFO’s were, however, believed to have come from a different source, leaks in a concentrate container at Stewart used to make firefighting foam. The PFO’s at Beaver Dam Lake are believed to have come from fighting a fire caused by the crash of a FEDEX airplane. Readings of the surface water at the lake when tested were minimal, but several homeowner wells were impacted and their homes fitted with POET filters.
As we go to press, there are reports that there is further discussion of incorporating a “cofferdam” during reconstruction (a cofferdam, also called a coffer, is an enclosure built within, or in pairs, across a body of water and constructed to allow the enclosed area to be pumped out.) With a cofferdam the contractors in charge of the project would have greater control over both the pressure at the dam site and the speed at which the lake empties. This would likely cause less disturbance to the problematic sediment and give added protection to the Moodna Creek. This type of dam reconstruction also gives added protection in the event of a flood. Denega said he will be discussing the possible benefits of this option with the DEC. With a cofferdam solution it may be that all of the water in the lake may not need to be emptied. Contractors could lower it as needed.
Meanwhile, the City of Newburgh is also pressing the state to filter water going to Washington Lake before they begin a plan to empty it into Silver Stream, which also ends up in the Moodna Creek before going to the Hudson River. City Manager, Michael Ciaravino continues to press for correction at the Stewart source, or Washington Lake, which continues to rise, could become a source of pollution to the Moodna Creek, or flood over its banks into neighboring residential areas.
Formal approval of the Beaver Dam project legislature funding will depend on a vote by the Orange County Legislature, possibly in June.
Funding for the project will come from a $1 M state grant and monies charged back to the lake district over the span of 15 years. The county is allocating temporary funding of $900,000 to get the project started, monies that will be repaid, thus resulting in no increase in county taxation.
There are many different designs of cofferdams, depending on the site.