There are many complaints about hydraulic fracturing, some of them real and some of them imagined. Complaints include everything from too much noise due to trucks and compressors used at hydraulic fracturing sites in the Dallas suburbs, to sudden entry of flammable methane into drinking water wells in Pennsylvania. So the impacts of hydraulic fracturing on the availability of freshwater for other purposes may seem trivial for people dealing with the immediate impacts disturbing their lives. But for some western states, the competition for water in a dry climate can be significant and a cause for concern. After all, there are few surface water resources in arid climates and the surface waters which exist are often fully utilized for domestic drinking water, agriculture and existing industry. People who live in dry climates sometimes rely heavily on groundwater, which is also a limited resource. A new use of groundwater for hydraulic fracturing can potentially impact an aquifer being used by households, farmers, and existing industrial operations.

 

How much water does a hydraulic fracturing operation need? The U.S Environmental Protection Agency’s Final Report on Impacts from Hydraulic Fracturing Activities on Drinking Water, states the median volume of water used per well is 1.5 million gallons. According to EPA, the average family of four uses about 400 gallons of water for domestic uses a day or 146,000 gallons a year. So hydraulic fracturing an oil and gas well uses about 10 times the amount of water a family uses in a year. Of course the 1.5 million gallons is the median, which means half of the wells being hydraulically fractured used less water and half used more. The amount of water used per well is dependent on the type of rock formation being fractured and whether it is a vertical well or a horizontal well. Fracturing shale requires more water than fracturing sandstone. Oil and gas wells which have been drilled horizontally require more water to fracture the rock than vertical wells.

 

Where does all this water come from? In the east, it mostly comes from surface water. For example, EPA’s report shows that in Pennsylvania and West Virginia about 90 % of the water used in hydraulic fracturing comes from surface waters like rivers and streams. In the west, the water for hydraulic fracturing comes mostly from groundwater. For example in Texas, 50 to 100 % of water used in hydraulic fracturing is sourced from groundwater. EPA says nationally, only about 5 % of water used in hydraulic fracturing is reused. So basically, the oil and gas business is using almost exclusively fresh water resources for hydraulic fracturing. Nationwide in 2012, the oil and gas industry used 52 billion gallons of water across 20 states to hydraulically fracture their wells. EPA says this is a small number compared to water being used for other purposes, such as drinking water and irrigation. Nationally, less than 1 % of water usage is for hydraulic fracturing.

But in certain areas, especially the dry western states, the percentage of water usage for hydraulic fracturing is greater. Of 401 counties reporting water usage data by the oil and gas industry, there are 26 counties where 10 % or more of the water usage in the county is for hydraulic fracturing.

 

This is where I have to scratch my head a little bit and wonder why EPA wanted to compare the use of a water resource for hydraulic fracturing against the use of the water for other purposes. In a county with no lack of water resources, the comparison makes no sense as there is abundant water for new uses. In a county with limited water resources, the comparison makes no sense either as there is little water for any use. Most of the counties where the use of freshwater for hydraulic fracturing is large compared to other uses, depend on groundwater. As mentioned above, groundwater is a limited resource. In the arid west, new water entering an aquifer is often less than what is being pumped out of the aquifer for domestic, agricultural and industrial uses. There are many aquifers in the mid-west and west which are being depleted as a result of over pumping of the groundwater. Sometimes fresh groundwater in certain areas of the west is being pumped so much that salty water from other aquifers is beginning to intrude into the freshwater aquifer. As a result, some towns have had to build desalination plants in order to provide people with drinking water.

 

I suppose the EPA wants to use this comparison to say overall there is little impact nationally on water usage due to hydraulic fracturing. But that only tells part of the story. After all, hauling water long distances adds to the cost of hydraulic fracturing. So water tends to be sourced fairly close to the oil and gas wells. If the source is a nearby stream then taking 1.5 million gallons from it can certainly have some impacts to the local flora and fauna and to people using the water downstream. EPA’s report points this out as a concern in Pennsylvania. Fortunately in that state, there is some government regulation of stream flows to limit impacts from water withdrawals.

 

Ditto, there is a concern where groundwater resources are limited, like in Texas and North Dakota. Again the water for hydraulic fracturing is sourced locally, usually by drilling a water well nearby. If groundwater is pumped significantly for use in hydraulic fracturing, it may affect the quantity of water available from the aquifer for other uses.  Although this may be happening in only a small number of counties, water managers have expressed concern about the potential impacts to households and farmers using the same groundwater aquifers as those now being utilized as a source of water for hydraulic fracturing. Water managers in a number of counties in Texas and North Dakota are having to make some hard decisions. For example, in North Dakota there was a concern among water managers about the increased pumping of groundwater from the Fox Hills aquifer for use in hydraulic fracturing. They feared that over pumping the aquifer for this new use would end up destroying the artesian flow of the groundwater. Artesian flow means the groundwater rises to the surface (without the aid of an electric pump) as a result of the natural pressure on the aquifer from overlying rock. This is important in rural areas where you don’t have a lot of electric lines to run a pump. In 2012, the state worked with the Corps of Engineers on a study to determine the availability of water for hydraulic fracturing from a reservoir on the nearby Missouri River as a replacement for the groundwater. As a result of the study, the Corps of Engineers determined 32.6 billion gallons of surface water from the reservoir could be made available for the oil and gas industry and for other municipal and industrial uses.

 

So the issue of impacts to drinking water resources from the acquisition of water by the oil and gas industry for use in hydraulic fracturing is a local one. The use of national water usage numbers is probably not a significant way to express the impacts of hydraulic fracturing on drinking water resources.