When a large tanker truck pulls up to a fire hydrant in Greeley, Colo. -- a midsize town on the semiarid Eastern Slope of the Rocky Mountains -- and starts siphoning water from the city's supply, passersby start looking nervous.
Chances are good the tanker is on its way to an oil or natural gas field, where the water will either go to drilling or be injected underground to reach previously inaccessible resources via a process known as hydraulic fracturing, or "fracking."
Such water transfers are becoming an increasingly common sight. But in a region that has battled drought on and off for decades, and where state officials predict there won't be enough water to sustain expected population and agriculture levels in the not-too-distant future, the tankers spark questions about how water is being used.
A high-profile groundwater contamination case in Pavillion, Wyo., is the latest to stir public debate on the pollution that can stem from hydraulic fracturing, but the amount of water used during extraction is an issue just starting to surface.
In what many are calling the first attempt to document how much water is required for hydraulic fracturing in the Centennial State, the Colorado Oil and Gas Conservation Commission (COGCC) released a fact sheet late last month that projected a 35 percent increase from 2010 to 2015 in water use for oil and gas exploration and production.
Water demand for hydraulic fracturing in the state is expected to increase from roughly 4.5 billion gallons in 2010 to more than 6 billion gallons in 2015, a jump that could supply more than 160,000 people with domestic water for a year.
In fracking, water is used to increase well production. Chemically treated water is pumped into the earth at high pressures, forcing open fissures that allow deep deposits of oil and natural gas to flow into wells.
A typical well site can require anywhere from 200,000 to 5 million gallons of water a year, according to Tisha Schuller, president and CEO of the Colorado Oil and Gas Association (COGA), which represents industry interests. That includes water for drilling and in some cases multiple rounds of hydraulic fracturing.
The amount of water used depends on the geology of the region and whether wells are drilled horizontally or vertically, according to the COGCC. Horizontal wells require more, as do shale formations located deep underground.
COGCC estimates that between 2010 and 2015, barring any major economic, environmental or technological changes, the number of active oil and gas wells in Colorado is likely to remain steady, with much of the expected 1.5-billion-gallon increase in water use linked to an expected swing from vertical oil drilling to new horizontal technologies.
More fracking means more water
Those estimates include the early end of new plans for large-scale, long-term projects like shale oil development in the northeastern part of the state, near Greeley. Late last year, Anadarko Petroleum Corp. and Noble Energy announced that they would invest billions of dollars to develop more wells in an effort to access an estimated 1 billion barrels of oil under the Niobrara shale oil field, according to Schuller.
"It's important to understand that the projections of operators like Anadarko will unfold over time and will not burst onto the scene all at once," said Todd Hartman, a spokesman for the Colorado Department of Natural Resources, meaning the industry's expected water use in the region beyond 2015 remains an open question.
Laura Belanger, a water resources and environmental engineer at Western Resource Advocates, is worried about the unknowns linked to the new fracking activity: the acceleration of hydraulic fracturing development, its proximity to populated areas, and a lack of data on water quantity needs and water quality impacts.
"It's happening so fast, so we don't know what we're getting into," she said. "We want to make sure decisions are being made based on as much information as possible; otherwise, we deal with the impacts after the fact instead of ahead of time."
Belanger said the state's new fact sheet is a good start, as are new state chemical disclosure rules for fracking, but she would like to see local data for the areas most affected by oil and gas development.
"We're not opposed to fracking," she added. "We just want to make sure we have all the information we need to decide."
One concern is whether a commitment of water resources to drilling means a sacrifice of population growth. In Weld County, where Anadarko and Noble are busy at work, Belanger's group estimates the new wells will drink up between one-third and two-thirds of the county's water.
"That's significant," she said. "Many of the communities in Weld County estimate large future water supply shortfalls. Oil and gas reserves in Weld County are likely to maintain new well development long into the future. So over time -- and perhaps sooner in dry years -- there is likely to be competition over limited water resources. This needs to be understood and planned for."
According to Colorado water law, oil and gas companies can secure the water they need by leasing from municipalities and farmers, tapping unclaimed groundwater, importing it from another state or, in rare cases, vying for unappropriated surface water.
COGA President Schuller said "companies face the same opportunities and challenges with regards to water development as any other water user." She explained that some companies have multi-year agreements or long-term water rights, and some don't. "Companies are participants in community water discussions in the same way that farmers, ranchers, developers and other industries are."
It is also not uncommon for oil and gas operations to recycle water used in drilling and extraction operations. Water used for drilling or fracking is considered waste under Colorado regulations and must be properly disposed of, meaning it is not returned to rivers and lakes, as much of the water dedicated to municipal and agricultural uses eventually is.
Belanger would like to see the state track how water leased to oil and gas companies is being used, how much of it is being recycled on-site, and how it is ultimately disposed of.
Jon Monson, director of the water and sewer department in Greeley -- the Weld County seat -- said citizens have expressed concern about the tanker truck water withdrawals. But Greeley, like many Colorado cities, has accumulated surplus water rights over time in an effort to meet its long-term needs and stave off the potential impacts of a temporary shortage.
Last year was an "epic water year," he said, leaving the city plenty of extra to sell. "Once you start explaining it is an annual surplus, and we are not committing to these people long-term," there is a bit of an attitude change, he said.
Last year, Greeley leased $1.5 million worth of water, or around 326 million gallons, primarily to oil and gas companies, as well as almost 9.8 billion gallons to neighboring farms. But the city makes more from the oil and gas deals because the water it sells to those operations is treated and therefore more expensive, according to Monson.
The water surplus "can make money for the citizens of Greeley," he pointed out.
A drop in the bucket?
Industry defenders argue that the water used in fracking doesn't add up to much.
Hydraulic fracturing technologies have been used in the state since the 1970s. "Hydraulic fracturing is ubiquitous," explained DNR spokesman Hartman. "It's safe to say the vast majority of wells today -- in Colorado and nationally -- are fractured."
In recent years, Colorado has been one of the most active Rocky Mountain states when it comes to hydraulic fracturing, according to Hartman. But the COGCC and industry also emphasize that the oil and gas industry's water footprint is minuscule compared with those of other users.
According to COGCC numbers, hydraulic fracturing represented just 0.08 percent of all water used in Colorado in 2010. Hydraulic fracturing used less water than agriculture, municipalities, industry, recreation or thermoelectric power generation.
The biggest user of water in Colorado, and the United States in general, is agriculture, usually accounting for up to 70 percent of water consumption. According to the COGCC, farming, ranching and other agricultural operations accounted for more than 4.6 trillion gallons, or 85.5 percent, of Colorado water use in 2010. Municipal and industrial uses combined accounted for about 397 billion gallons, or 7.4 percent.
Belanger said the comparisons to agriculture are misleading. Colorado has invested "significant time and money evaluating and planning for municipal and industrial water needs," she explained, even though those uses account for a small percentage of the total.
"The amount of water needed to drill and frack new wells each year is significant," said Belanger, "and similar to municipal and industrial uses, natural gas development needs to be planned for. We must carefully assess where the water will come from, what the impacts will be, and decide if this is how we want to allocate a significant portion of our limited water resources."
Eichenseher is a freelance journalist based in Boulder, Colo.
Correction: An earlier version incorrectly stated the amounts of water the COGCC says went toward agricultural operations and municipal and industrial uses in 2010.