Some Thoughts on Wetlands and the Marcellus Shale Formation

The Marcellus Shale formation and its natural gas deposits are proving to be a major economic driver for the east coast and mid-west. The formation extends from upstate New York, west to Ohio and south to Virginia. It is one of, if not the largest natural gas deposit ever found. The long term energy implications are profound.

However, there are a number of environmental issues that must be addressed. Chief among these is method in which the gas is extracted. The technique is called hydraulic fracturing. In the industry it is also known as "fracking." It is a process that results in the creation of fractures in rocks. The fracturing is done from a wellbore drilled into reservoir rock formations to increase the rate and ultimate recovery of oil and natural gas.

Hydraulic fractures may be natural or man-made and are extended by internal fluid pressure which opens the fracture and causes it to extend through the rock. Natural hydraulic fractures include volcanic dikes, sills and fracturing by ice as in frost weathering. Man-made fluid-driven fractures are formed at depth in a borehole and extend into targeted formations. The fracture width is typically maintained after the injection by introducing a proppant into the injected fluid. Proppant is a material, such as grains of sand, ceramic, or other particulates, that prevent the fractures from closing when the injection is stopped.

The process is more or less a drill, pump and recover system. The gas trapped in the void spaces is forced out under pressure and captured. When done correctly this can be a very efficient way to develop the gas well.

At issue is the water impacts associated with this type of recovery system. First you must have an ample supply of water. Local surface and ground water supplies are limited. Second, the "fracking" technique requires proppant. This proppant may be a source of additional concerns. Other things like emulsifying agents, flocculating agents, and surface-active agents are also added to the injection water. These can pose their own issues.

Other environmental concerns relate to the operation and maintenance of the gas well. The potential for spills of industrial chemicals is always a concern. The injection water is also a concern as it finds its way in and around the aquifers.

From a wetlands perspective the main issues to keep an eye on are focused on the citing of the well, the impact to surface and groundwater and the effects of the injection waters both from a source and discharge point of view. Obviously, locating a well in a wetland is probably a bad idea. However, there are gas wells in wetlands. The Leidy storage field is a good example. The major wetland concern is the drawdown of water for injection going to have an adverse impact on the surrounding wetlands? Also, will the discharge water impact the quality of the watershed?

I am sure that there are a number of other issues associated with the exploration and development of the Marcellus Shale formation. Wetland mitigation and delineation are key to developing this as a sustainable resource. My hope is that working together we can find and economic and environmentally safe way to explore this natural resource.


In response to the demand for qualified environmental biologists, The Swamp School has added a new class to our list of Spring Wetlands Classes. This new class is focused on the wetlands issues associated with the Marcellus Formation and is being held in Bucks County, Pennsylvania. More information about this class can be found ==>HERE.

Have a great week!


Marc