By James Laughlin, WaterWorld Editor
Groundwater accounts for about one third all the water used by U.S. municipalities, and some 44 percent of the U.S. population depends on groundwater for its drinking water supply — be it from a public source or private well.
Groundwater across the United States is under a variety of stresses, with over-use in some regions, contamination in others, and a renewed threat from oil and gas production. Most of the drinking water systems that provide groundwater to their customers are small, and many of those systems are challenged to meet regulatory standards, according to Kevin McCray, Executive Director of the National Groundwater Association.
"If you look out to all public water systems in the United States, both community and non-community, there are about 150,000 of those. The vast majority are small, serving 10,000 or fewer people, and 99 percent of those are supplied by groundwater," he said.
The NGWA is sponsoring Groundwater Awareness Week March 11-17, with the goal of raising the public's awareness and understanding of groundwater issues.
While groundwater is often a clean, reliable source of drinking water, it is stressed by growing populations in some regions and intensive irrigation in others.
"There are regions of country that have the challenge of managing their water resources because of significant population growth. Many are located in water poor regions to begin with and when you throw drought on top of that, they have significant challenges," McCray said.
However, agriculture is by far the largest user of groundwater in the United States. Some 53.5 billion gallons of groundwater are used daily for irrigation. Compare that to an estimated 34 million gallons per day treated by municipal utilities from all sources, with groundwater representing only about a third of the total.
More than 90 percent of the groundwater pumped from the Ogallala, the nation's largest aquifer underlying some 250,000 square miles stretching from Texas to South Dakota, is used for agricultural irrigation. Representing about one-third of all U.S. irrigated agriculture, it creates about $20 billion annually in food and fiber.
Irrigation does come with a price – water levels in the Ogallala and other aquifers are dropping, and as the water level goes down, the cost of energy to pump that water goes up. Companies, and individuals, are beginning to understand that pumping like there is "no tomorrow" is no longer an option, McCray said.
"People realize there is a tomorrow and we have prepare for it now," McCray said. "They are doing some things in terms of management to keep that aquifer viable for as long as they can."
One new trend seen as a threat to groundwater quality has been the sudden explosion in oil and gas exploration around the country. Hydraulic fracturing to promote natural gas production has been the focus of media attention recently, but oil sands and more traditional oil well exploration also carry risks to the environment and groundwater.
The Environmental Protection Agency is undertaking a national study to understand the potential impacts of hydraulic fracturing on drinking water resources. The study will include a review of published literature, analysis of existing data, scenario evaluation and modeling, laboratory studies, and case studies. EPA is expected to release initial study results in a 2012 report and an additional report at the end of 2014.
"If best practices are not followed by oil and gas production, there is some potential for risk to water supplies," McCray said. "It's critical that the oil and gas sector realize they have an accountability and responsibility for preserving water supply.
"It takes oversight, it takes conscientious practices, and continued research and science to make sure those practices are working as well as intended, and then adding improvements to them when we discover better ways of doing it," he said.
Although his organization's focus is on groundwater, water both on the surface and below ground are all part of the same system and must be managed together as part of an integrated water management strategy, McCray said.
"Everyone is coming to grips with the fact that they have to be smarter about the application of water resources," he said.
That comes through public education and a fundamental change in attitude about water. McCray said the municipal water industry has done a good job over the past few years promoting the importance of protecting water resources.
He pointed to efforts of the Edwards Aquifer Authority in the San Antonio region of Texas. The authority has an active aquifer education program. Residents can even get near real-time data on aquifer levels (As I write, current level 660.7.)
"They are very conscientious about their water and they have made it a public conscientiousness, which is probably the most critical thing," McCray said. "You go down there and turn on the news and the weather report also includes what the groundwater levels are. That's the kind of engagement that you need the citizenry to have. Then they start to understand that everything they do has a consequence. And it's in their own best interest to use the water as wisely as they can."
McCray also noted the work of the Orange County Water Management district in Southern California.
"They manage every drop of water in and out of that systems, and that enables them to sustain high intensity population and high intensity businesses and industry," he said.
"The water industry does a great job of trying to keep people aware of the importance of water stewardship," McCray said. "We need a citizenry that is engaged and understanding that what they do has an impact on the resource."
For more information and educational resources associated with National Groundwater Awareness Week, visit www.ngwa.org. Additional resources may be found on the EPA Water website: http://water.epa.gov/type/groundwater/awarenessweek.cfm
Orange County Begins Expansion of Groundwater Replenishment System
The Orange County Water District (OCWD) recently broke ground on a project to expand its Groundwater Replenishment System. Located at the OCWD Advanced Water Purification Facility in Fountain Valley, CA, the $142.7 million project will create an additional 31,000 acre-feet per year of new water supplies to serve north and central Orange County. Once completed, the AWFP's total production will reach 103,000 AFY, enough water for 850,000 people.
The Groundwater Replenishment System, a joint project of OCWD and Orange County Sanitation District, takes highly treated wastewater that would have normally been discharged into the Pacific Ocean and purifies it through a three-step process that includes microfiltration, reverse osmosis and ultraviolet light with hydrogen peroxide. 35 million gallons of near-distilled quality water per day is pumped into injection wells where it serves as a seawater intrusion barrier. Another 35 million gallons per day is pumped 13 miles to OCWD recharge basins in Anaheim, CA. The water then filters through sand and gravel to replenish the deep aquifers of Orange County's groundwater basin and ultimately becomes part of the drinking water supply.
|The Orange County Water District expansion project will include construction of a new 30 mgd treatment facility. Photo Credit: Larny Mack, courtesy of CDM.|
Serving as general contractor for the expansion, McCarthy Building Companies Inc. will construct a 30 mgd treatment facility expanding the 70 mgd plant that was completed in 2008. Parsons of Pasadena is construction manager for the project and Black and Veatch of Irvine is the structural, civil, electrical and mechanical engineer.
The project entails expansion of the existing microfiltration facility by constructing eight new below-grade treatment basins and enlarging the existing basement facility. Other work includes construction of a new 32,000-square-foot reverse osmosis building, the installation of five new ultraviolet light treatment trains to match the existing systems, as well as retrofitting the existing post treatment systems to employ a new lime feed system.
Construction is scheduled to be complete in September 2014. For more information about the project, go to www.gwrsystem.com.