The U.S. Geological Survey (USGS) and New York State Department of Environmental Conservation (NYDEC) recently completed a study of dissolved methane in groundwater.
Unlike Pennsylvania, New York is taking steps to document the existence of dissolved methane in groundwater before gas development in Marcellus and Utica shale
occurs.
The report contains some good background information on methane and groundwater. For example, the report explains the basics on how methane dissolves and is released from water. Methane can dissolve in water just like carbon dioxide gas used in carbonated beverages. When pressure is reduced, as occurs when the top is removed from a bottle, gas comes out of the solution and causes bubbling and fizzing in the beverage. The same occurs in groundwater. Methane can be dissolved in water under extreme pressure beneath many layers of rock. When that rock is fractured and the water enters a location under less pressure, such as a water well, the dissolved gas can be released, resulting in bubbling water. If the gas is released in a closed structure, such as a home or water tank, the concentration of gas can become flammable and explosive.
The report also explains the scientific basis for safety levels used by state and federal officials. Methane reaches saturation in water at 28 milligrams per liter (mg/L) at atmospheric pressure and becomes flammable in air at about 5 percent by volume. For this reason, the federal government recommends that action be taken to closely monitor water that contains methane concentrations from 10 to 28 mg/L (or 3 to 5 percent by volume in air). Concentrations of methane less than 10 mg/L in water (or 1 to 3 percent by volume in air) are not as great a concern, but the gas should be monitored to ensure no buildup over time.
The study is comprehensive — involving 239 locations and encompassing eight of 14 major river basins in the state. For samples collected through 2011, the study concluded that a full 91 percent of wells over varied conditions throughout the state contain methane below the federal action level of 10 mg/L, and that nearly half (47 percent) contain no measurable amounts of methane. In only five cases (2 percent of the total number of samples) did the methane concentration exceed 28 mg/l.
Friday, September 28, 2012
New York Monitors Groundwater for Methane To Prepare for Shale Gas Development
Interestingly, the report broke down the data dependent upon whether the water samples came from unconsolidated or consolidated (bedrock) aquifers. Methane was found in both, but in varying numbers. Effectively no methane could be found in a full 93 percent of samples collected from unconsolidated aquifers, and only 1 percent had levels exceeding 28 mg/l. Even in wells drilled into bedrock, where one would expect to find methane dissolved in water, 73 percent effectively had no methane, while 4 percent contained concentrations greater than 28 mg/l. Three of the four highest methane concentrations all came from wells drilled into one particular type of shale. These findings appear to suggest that the location and depth of groundwater wells might provide a screening tool for determining where funds should be expended to test for methane concentrations in water.
It is unfortunate and contrary to the public interest that the Pennsylvania Department of Environmental Protection (DEP) performed no baseline monitoring similar to that being done by the NYDEC. Although the DEP has a statutory obligation to investigate individual claims that drilling contaminated drinking water supplies, each such claim and investigation consumes DEP resources. And while drilling companies are obligated to offer to collect samples from drinking water sources within a specified distance of a proposed gas well, the companies have no authority to require that a sample be collected, and the specified distance was established by the General Assembly arbitrarily and not based on any factual or scientific data. Further, the sampling requirement is based on a distance horizontally from the well, and does not account for laterals that will eventually be used to fracture the shale. If a claim of contamination is made by a resident and DEP concludes that it cannot prove that the drilling caused the contaminated water in the well, then the landowner is left to pursue an action on his or her own against what is likely to be a well-funded defendant. Alternatively, the company may choose to spend resources to satisfy the complainant as a matter of doing business even though it genuinely believes that it has no responsibility for the contamination. Even if the landowner has funds to pursue an action or if the government steps in because more than one home has been allegedly affected, the result will likely be a substantial expenditure of public and private resources resolving the dispute. None of these scenarios is an efficient means of doing business or protecting the public health and safety.
By developing baseline data of dissolved methane content in its aquifers before shale gas development begins, New York is serving the interests of both residents and the industry. The study will not resolve all disagreements, but it will provide substantial data against which to compare the impact of the industry when it arrives and should lead to the more efficient resolution of individual disputes, particularly if New York couples the baseline data with adoption of a law that requires gas companies to collect water samples of nearby drinking water supplies and requires that residents submit to that sampling or document well conditions that prevent the sampling from taking place.
It is unfortunate and contrary to the public interest that the Pennsylvania Department of Environmental Protection (DEP) performed no baseline monitoring similar to that being done by the NYDEC. Although the DEP has a statutory obligation to investigate individual claims that drilling contaminated drinking water supplies, each such claim and investigation consumes DEP resources. And while drilling companies are obligated to offer to collect samples from drinking water sources within a specified distance of a proposed gas well, the companies have no authority to require that a sample be collected, and the specified distance was established by the General Assembly arbitrarily and not based on any factual or scientific data. Further, the sampling requirement is based on a distance horizontally from the well, and does not account for laterals that will eventually be used to fracture the shale. If a claim of contamination is made by a resident and DEP concludes that it cannot prove that the drilling caused the contaminated water in the well, then the landowner is left to pursue an action on his or her own against what is likely to be a well-funded defendant. Alternatively, the company may choose to spend resources to satisfy the complainant as a matter of doing business even though it genuinely believes that it has no responsibility for the contamination. Even if the landowner has funds to pursue an action or if the government steps in because more than one home has been allegedly affected, the result will likely be a substantial expenditure of public and private resources resolving the dispute. None of these scenarios is an efficient means of doing business or protecting the public health and safety.
By developing baseline data of dissolved methane content in its aquifers before shale gas development begins, New York is serving the interests of both residents and the industry. The study will not resolve all disagreements, but it will provide substantial data against which to compare the impact of the industry when it arrives and should lead to the more efficient resolution of individual disputes, particularly if New York couples the baseline data with adoption of a law that requires gas companies to collect water samples of nearby drinking water supplies and requires that residents submit to that sampling or document well conditions that prevent the sampling from taking place.
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