Recent statements from Community Energy claim that only some parts of the Jordanville Wind Project area are subject to problems from karst geology. In saying this, the company shows that it doesn’t understand the nature of karst landscapes.
All of the uplands in the project area consists of limestone, virtually without exception.
The limestone was formed over 400 million years ago when shallow tropical seas overlay most of eastern central New York State and teemed with shellfish and reef”“building animals like corals. These created the carbonate that made the limestone.
The formation is called Helderberg limestone after the Helderberg Hills where it was first identified.
Because limestone is so resistant to water erosion, it mostly prevents underlying rock formations from eroding away the way the sandstones and shales in the Otsquaqo and Mohawk valleys have done.
That’s why the uplands are up there where the wind blows.
But there’s a catch. The limestone cap rocks mostly prevent erosion ““ but not completely. Because they overlie much softer rock, any water that does seep down through cracks and disconformities carves out caves beneath. Sometimes the cap rock surface over caves fractures to form sinkholes.
That’s what karst is all about. The Helderberg limestones are like castles built on foundations of sand.
When Community Energy says it can get around this problem by proper siting of the turbines ““ presumably testing a location by drilling down to see what’s underneath ““ they either don’t understand what is involved here or are not being frank.
The fact that they claim the Sickler Road area, where many turbines are to be placed, is not a karst landscape suggests the latter, because there is a large sinkhole with a deep cave entrance just to the east of Sickler Road on the top of the hill and many limestone outcrops all around.
All of this limestone is bedded on top of soft, easily eroded sandstones and shales.
A Community Energy representative told a local reporter that each turbine weighs about as much as a filled silo, implying that because silos have been here for years, the weight of the turbines is not a problem.
But though turbines and silos are indeed roughly the same weight, no silo includes the huge concrete foundation weighing almost 2,000 tons (1,865) needed to anchor a wind turbine. Of course, 400-foot turbines need massive anchoring to keep them in place. Comparing such a construction to a silo is ridiculous.
The problem of karst geology is that it is inherently unpredictable. Simply because turbines are placed on sites that today have no caves underneath is no guarantee they will remain that way.
Water continues to flow underneath the hard limestone cap rocks, eroding the soft shales and sandstones. Almost certainly the construction of 68 turbines will create new cracks and fissures underground that will change water flow in unpredictable ways, ways that among other things could affect local water supplies and private wells.
Proper maintenance of such a facility should include constant monitoring of underground water flow.
Does it make sense to trust a company that:
1) had no idea it was planning to build in a karst landscape until informed by interested private citizens;
2) now proposes inadequate safeguards to address the problem; and
3) continues to put out rank misinformation such as the weight of the turbines?
Is this a track record people feel comfortable with in a company that wants to make huge, irreversible changes in the local landscape?
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