As the Trump Administration and new Congress debate the details of a national infrastructure program that could cost $1 trillion, one glaring need cries out for attention: water resources.

Water, in one form or another, has been grabbing headlines across the country –

· Even a rainy winter can’t begin to solve California’s acute water shortages made worse by a five-year drought.

· The water level in Nevada’s Lake Mead, the nation’s largest reservoir, has sunk to its lowest level ever.

· A massive water-main break involving 130-year-old pipes flooded homes and business in Denver in January, while another break in Boston drowned two construction workers.

· Government officials in Michigan have come under criminal charges from a toxic water crisis in Flint.

· Extensive 2016 flooding, meanwhile, battered such states as Texas, Louisiana, Oklahoma, Missouri, West Virginia and the Carolinas.

The list of water-related issues goes on, and the price tag for fixing the problems could eclipse even the most ambitious government construction campaign. The American Society of Civil Engineers estimates that it will take a $2.5 trillion investment to repair the country’s aging water infrastructure.

(Read "How Engineers Can Adapt Infrastructure Design for a Changing Climate.")

Such initiatives also require an arsenal of engineering solutions, which can vary from city to city, and region to region, says Richard Luthy, a leading national expert on water resources. A professor of civil and environmental engineering at Stanford University, Luthy also serves as the director of the National Science Foundation’s Engineering Research Center for Re-Inventing the Nation’s Urban Water Infrastructure (ReNUWIt).

In an interview with Engineering360 contributing editor Larry Maloney, Luthy discusses how engineering innovation and technology can help ease the nation’s water woes.

Maloney: Just how serious are water resource and infrastructure problems in the U.S.?

Richard LuthyRichard LuthyLuthy: The situation differs from area to area, but one problem that is common around the country is the badly aging water infrastructure. Much of this cast-iron-pipe network was built 70 to 100 years ago and is at the end of its design life. It will take enormous investments to repair and replace this infrastructure.

In its latest state of the water industry report, the American Water Works Association puts the costs of repair at about $1 trillion. Other groups peg needed investments at $400 billion for drinking water and $300 billion for waste water. You can quibble about the exact amount, but it is vast – likely $1 trillion to $2 trillion.

Maloney: Your state – California – has certainly experienced the water crisis firsthand.

Luthy: Here in California we are in a perpetual state of water scarcity, and the problem became more acute as we entered the 21st century, so we need to respond more aggressively than ever.

The state is essentially a dry place, and it gets progressively drier as you move down from the north to San Diego, which receives only about six inches of rain a year. From its very beginning, the state experienced squabbles between the water needs of urban areas and those of California’s extensive agriculture regions. Those needs have traditionally been met by importing water from long distances, but that solution has come at the expense of ecosystems, including rivers drying up in the summer because of all the water extractions. Add to these problems such factors as a growing population and the impact of climate change, which is causing more intense dry periods, as well as more intense wet spells.

Climate change also has been accelerating the snow melt in the Sierra Nevada Mountains, which is creating new flood control challenges in important reservoirs like Lake Oroville. (Read "Highest Dam in the U.S. Faces Threat.")

Maloney: Beyond California, what are some of the other parts of the country that are facing serious water shortage problems?

Luthy: Climate change is making dry areas even drier, which means more acute water supply concerns in such areas as Arizona, Texas, Georgia, and Florida. With the water supply of Atlanta and agricultural interests at stake, as well as oyster beds in Apalachicola Bay, Georgia has been battling with Florida over water rights involving the Apalachicola-Chattahoochee-Flint River Basin. And Tampa was the first city in the nation to build a seawater desalination facility to augment its water supply.

Maloney: Looking at some of the engineering solutions being suggested to meet these challenges, how important is stormwater harvesting?

Luthy: The City of Los Angeles, which already has some stormwater catch basins in place, is a good example.

These basins, most of which are situated below hillside dams, capture about 65,000 acre-feet a year of water, along with incidental recharge from the surrounding area. But these basins typically do not capture rains that fall on streets and roads.

Heavy rain in February 2017 threatened the Oroville Dam in California.Heavy rain in February 2017 threatened the Oroville Dam in California.You could double or triple the amount of water captured by upgrading these basins and building new recharge basins, which could then provide 25% or more of the city’s water needs. So the potential is there.

What is driving the interest in this approach is that the city must now import half of its water from sources in Northern California and the Colorado River. But these imports are unreliable, and the city wants to cut these imports in half, and to do that it must rely on three approaches: stormwater capture, recycling/reuse, and conservation.

Maloney: What are some of the interesting approaches you are seeing in water recycling?

Luthy: One of the interesting new techniques we see in California is the use of small, decentralized recycling systems near the places where waste water is generated.

There are clear advantages to this approach. You eliminate the need for long networks of water pipes for pumping the water from large-scale water treatment plants, which typically are located miles away from the homes and businesses that need the water. You also have lower salt content in the water, because you don’t have infiltration of brackish water as you frequently do at large treatment plants located near bays.

In addition, these smaller plants make it easier to introduce innovative, energy-efficient biotechnology processes for water reclamation, such as the use of microbes that treat waste water without oxygen and convert organic matter to methane to help power the plant. With membrane technology, you also end up with a very fine filter that produces very clean water that with disinfection is suitable for irrigation and other non-potable uses.

Maloney: On the conservation front, can you cite some examples of innovative approaches implemented by governments or water users?

Luthy: California is a good example of what may well happen in other parts of the country.

With the state in the midst of a drought, Gov. Jerry Brown in April 2015 ordered cities and towns across the state to cut water use by 25%, versus what they used in 2013. This was the first-ever statewide mandated water restriction. To a great extent, the communities responded positively.

(Click to enlarge.) Schematic of a water desalination process.(Click to enlarge.) Schematic of a water desalination process.Data from the State Water Resources Control Board show statewide water savings of more than 22% in the June 2015 through December 2016 period. Conservation steps include cutting back on outdoor use and watering lawns, as well as use of landscaping that’s more compatible with our climate. In businesses, you see such steps as power plants using recycled waste water for cooling, as well as use of air cooling.

But there’s a new reality as we move further into the 21st century. Even though conservation efforts are prompting consumers and businesses to use less water, our water bills are going up. Utilities historically have based their rates on volumetric use. But now water bills need to cover not just the volume of water used but the costs of delivering water services.Where I live, about one-third of my water bill is for the water itself, the rest is for the service.

Maloney: Where does desalination fit as a solution to water shortages?

Luthy: Let’s look at the factors that led to construction of San Diego’s $1-billion Carlsbad desalination plant that opened in late 2015.

The city is essentially a desert. There are no aquifers and there is very little rainfall, so there is virtually no storm water capture. So outside of water reuse and recycling, there really is no viable option other than desalination. But desalination plants prompt pushback from environmentalists over such issues as energy use and the impact of water intake and brine disposal on aquatic life. So we need to proceed with caution on new desalination plants that process seawater.

However, desalination does make a lot of sense in applications involving brackish water and waste water, because the salt content is much lower, as is the energy needed in the process. With modern reverse osmosis technology, desalination can produce both potable and non-potable water from these sources. The amount of water available in these kinds of desalination applications is quite large.

Orange County California is already using this technique to a large degree, and moving forward you are likely to see this type of desalination used both in large central plants as well as in smaller decentralized facilities. In 2014, Silicon Valley launched an 8-million-gallon-a-day advanced water purification facility that upgrades wastewater to essentially drinking water quality.

Maloney: How effective are current filtration methods at water treatment plants in neutralizing the health threats from pharmaceuticals, steroid hormones, pesticides and the like?

Luthy: Our drinking water generally comes from good water sources. There are some cases where drinking water comes from effluent-dominated streams.

For example, the Trinity River, which flows from Dallas-Fort Worth to Houston, is largely wastewater from the Dallas metroplex during dry periods of the summer. But even here treated water meets federal and state standards.

Maloney: Are you concerned that clean water initiatives will take a hit, given the Trump administration’s criticism of environmental regulations?

Luthy: No. I don’t see any backing down on drinking water quality. That would be political suicide. Not after Flint. (The Michigan city where lead found its way into water supplies.) If there is any reduction in environmental regulation, it is much more likely to be in delaying tougher emission control standards on coal-fired power plants and relaxing rules that protect ecosystems and wetlands.

Maloney: You’re the director of the National Science Foundation’s Engineering Resource Center for Re-Inventing the Nation’s Urban Water Infrastructure (ReNUWIt) .What role does it play in promoting more sustainable solutions to water challenges?

Luthy: The organization encourages partnerships between university researchers and industry partners – namely the water utilities and water districts – on projects that demonstrate what is possible in the way of new technologies for managing water systems. The focus is on small pilot projects that we hope can eventually be scaled up for commercial use.

Stanford University's Codiga Resource Recovery Center. Stanford University's Codiga Resource Recovery Center. For example, on the Stanford University campus, a new project is just coming on line that demonstrates decentralized water reclamation. Called the Codiga Resource Recovery Center, it features a staged anaerobic fluidized bed membrane bioreactor that not only generates high quality water but converts organic matter into biogas methane to power the process.

Compared to conventional approaches, the system is expected to have lower operational and capital costs, and is very effective in removing trace contaminants, such as pharmaceuticals. Local water utilities are looking closely at this project and are interested in scaling it up in a larger facility in Redwood City, Calif.

Another ReNUWIt project looks at ways to redesign wetlands to improve water quality. We worked with the Orange Country Water district to build three large test cells to investigate how you can use a combination of photochemistry and microbial reactions to cleanse water before it is recharged into the ground. This concept will help shape the planned Rory M. Shaw Wetlands Park near the Burbank Airport. The project will convert a 46-acre landfill into a mixed use park that will include recreation areas and a detention pond to store runoff water and prevent flooding. Still other projects include ways in which stormwater capture systems and water reuse may work in tandem for greater Los Angeles.

Maloney: What is more important in solving water supply challenges: employing innovative technology or putting much more emphasis on conservation?

Luthy: When you discuss the future of water supply, you have to start with conservation. In the future, you are likely to see greater use of smart water meters and other devices that help consumers track water use. But conservation itself is not enough, because many areas, such as California, have already done a good job in that regard.

To a great extent, especially in California and the dry Sun Belt, progress in reducing per capita use of water is offset by population growth. This is why we must make continued progress on technologies for stormwater capture, recycling and reuse, water banking and exchanges, and, where appropriate, seawater desalination. Solutions will vary from place to place, but the techniques that get the traction will be ones that are supported not just by government officials and the water authorities but by all parties, including consumers, businesses and environmentalists.

Maloney: How do you view the current political climate when it comes to support for investment in water infrastructure?

Luthy: The heyday of federal government spending on water was in the 1970s, with the passage of the 1972 Clean Water Act and the 1974 Safe Drinking Water Act. That legislation had a marvelous impact on cleaning up the nation’s rivers and harbors and ensuring water quality. But that was nearly 50 years ago.

New investment is needed, but I am very doubtful that we will see the level of support that we did in the 1970s, when the federal government paid as much as 75% of project costs. Perhaps the federal government will provide low-interest loans or do some pump-priming with grants, but this is just speculation. It will likely fall to cities and states to make the bulk of water infrastructure investments, which means that consumers and businesses will have to pay more for water services. Ultimately, states and localities must take the lead in implementing new technologies for urban water systems.

Resources

Professor Richard Luthy bio sketch: http://web.stanford.edu/group/luthygroup/

American Water Works “State of the Water Industry” report: https://www.awwa.org/Portals/0/files/resources/water%20utility%20management/sotwi/2015-AWWA-State-of-the-Water-Industry-Report.pdf

National Science Foundation’s Engineering Research Center for Re-inventing the Nation’s Urban Water Infrastructure (ReNUWIt): http://www.renuwit.org/

National Academy of Engineering Water Science and Technology Board: http://dels.nas.edu/wstb

California Water Resources Control Board: http://www.waterboards.ca.gov/water_issues/programs/conservation_portal/docs/2017feb/pr020817_conservation_renewal.pdf

Desalination process and video: http://carlsbaddesal.sdcwa.org/desal-process/

Opening of San Diego’s Carlsbad desalination plant: http://www.nbcsandiego.com/news/local/Carlsbad-Desalination-Plant-Opens-361844511.html

Stanford University Codiga Resource Recovery Center: https://woods.stanford.edu/sites/default/files/files/CODIGA-Factsheet-FINAL-1-2016.pdf

Rory M. Shaw Wetlands Park: https://dpw.lacounty.gov/wmd/svw/wetlands.aspx

Luthy, R. G. and Sedlak, D. L., “Urban Water-Supply Reinvention,” Daedalus, American Academy of Arts and Sciences, 144(3), Summer 2015, http://www.mitpressjournals.org/doi/abs/10.1162/DAED_a_00343#.WK95lrkzWM9

Luthy, R. G., “The Price of Water Conservation—Using Less and Paying More,” Water Deeply, Sept. 26, 2016: https://www.newsdeeply.com/water/community/2016/09/26/the-price-of-water-conservation-using-less-and-paying-more\