© Reuters. Greenhouse technician Leah Greiner harvests sugar beets at Altius, a vertical farm in Denver, Colorado, U.S., on November 9, 2021. Photo taken on November 9, 2021. REUTERS/Kevin Mohatt/File Photo
by Donna Bryson
(Reuters) – In a rooftop greenhouse near downtown Denver, cash crops thrive on hydroponic life support. arugula. beet. snails. cabbage.
“And basil,” Altius Farms CEO Sally Herbert said, plucking a bright leaf. “You really should try it. Because it’s spectacular.”
Vertical farms are one of many models in Colorado’s response to growing water scarcity in the western United States, as climate change makes droughts more frequent and severe.
Other projects have had Coloradoans test water recycling and build barriers to wildfire runoff that could contaminate supplies.
Colorado is not alone. Half the world’s population is already facing severe water shortages for at least some parts of the year, according to a major recent UN climate report. In the western U.S., drought and early runoff will exacerbate summer water shortages due to less snowpack, the Intergovernmental Panel on Climate Change said.
Although Colorado has so far met the water needs of its 6 million residents, according to a possible scenario expert prepared for the state’s official water plan https://cwcb.colorado.gov/colorado-water-plan/technical-update-to -the-plan.
The region’s worst drought in more than a century has left the Lake Mead reservoir, which supplies water from the Colorado River to neighboring states, very low.
“It’s exciting,” Herbert said.
There is no single solution to ensure future water quality, quantity and affordability. Approaches such as water recycling face regulatory gaps and public resistance.
At the same time, vertical farming cannot achieve the scale required for major crops such as corn or wheat. While Altius uses mostly natural light to grow 25,000 pounds (11,300 kilograms) of produce annually on its 7,000-square-foot roof, others rely on light fixtures and electricity. This can drive up agricultural prices.
Still, vertical farms use 95 percent less water than conventional farming. Other benefits could include lowering transportation costs and bringing produce closer to where consumers live. Food that can be grown indoors could be a boon outside temperate regions, said Michael Dent, an agriculture and food technology analyst with IDTechEx’s market research group.
Those benefits are attracting investment: Georgia-based multinational Kalera is now repurposing a warehouse near Denver’s airport—close to a highway and a supermarket distribution center. Founded in 2010, the company grows agricultural products in the Middle East, Asia and Europe, with plans to expand further.
Retail giant Walmart (NYSE: ) Inc joined San Francisco vertical startup Plenty in a $400 million funding round in January, a deal still subject to regulatory approval.
Last year, New York-based vertical startup Bowery Farming raised $300 million in a funding round.
Assessing the overall environmental footprint of vertical farms can be difficult. For example, a farm that uses wind power will produce less polluting carbon emissions than a farm that uses fossil fuels.
Henner Schwarz, Kalera’s chief commercial officer, said, “Frankly, there’s a lot of smoke and mirrors. Everyone has the ‘most sustainable technology,’ and there’s a lot of crap, crap.”
“But when it comes to saving water, I’m actually pretty confident that we’re only using 3 percent of the water we use in conventional agriculture,” Schwarz said.
At a home construction site, a plumber huddles around a black, refrigerator-sized technical device.
Once connected, the system will siphon and filter shower and bath water, removing skin cells, soap and hair, before sending the water back to the toilet for flushing. “This is the first device to bring filtration to this level,” said Todd Moritzky, owner of the pipeline company.
His crew is building the house Renner (NYSE:) Castle Rock in south Denver. Using a filtration system made by Canadian company Greyter, household water consumption was reduced by up to 25 percent in earlier buildings, Lennar said.
“The water here is liquid gold,” said Eric Feder, director of Lennar’s Colorado-based national effort to embrace innovation in residential construction. He said the company wants to make the Greyter system the standard in its homes.
But in Colorado, Castle Rock and Denver and Pitkin counties are the only three communities that allow household water recycling.
“Plumbing codes, ordinances, local regulations are catching up with the availability of this technology,” said Pat Sinicropi, head of the WateReuse trade association.
Castle Rock receives less than 15 inches (38 cm) of precipitation per year. The town has a population of 70,000 and is expected to grow to 100,000 by 2060. It aims to reduce its daily water consumption from about 115 gallons per person to less than 100 gallons per person within a decade.
“We fully intend to make it happen,” said Castle Rock Water director Mark Marlowe. The utility now offers a fee discount for home developers if they have systems like Greyter’s installed.
safe to drink
Just south of Castle Rock in Colorado Springs, Tzahi Cath has been working with local utilities to demonstrate that recycled wastewater can be used not only for toilet flushing, but also for drinking.
An engineering professor at the Colorado School of Mines and his students in Golden built a portable water treatment lab to further treat wastewater partially treated by the utility, making it safe to drink.
The idea is not new. Since 2003, Singapore has been treating sewage and recycling water back to its reservoirs. Sewage recycling infrastructure is under construction in San Diego, California. Cath’s desert home, Israel, is a world leader in desalinating seawater for drinking and treating wastewater for irrigation.
From June to December, Cath produced half a million gallons of drinking water—serving the nearly 1,000 people who visited his lab. Most taste testers thought water was fine.
“The state needs to start investing, and utilities need to start building infrastructure” to allow utilities to clean and transport recycled wastewater for drinking, Cath said.
State officials are urging citizens to conserve water, while they also want to increase funding for infrastructure.
Under the state’s official water plan, the state needs at least 10 times the $25 million currently allocated in its annual budget to the Department of Natural Resources, which funds water projects.
In addition to concerns about having enough water, Colorado faces a growing threat of wildfires that could disrupt its existing supplies.
Last summer, the college town of Fort Collins had to let some water run off the Cache la Poudre River because it was contaminated with ash and debris from the previous year’s wildfires.
Wildfires have destroyed vegetation that normally absorbs some of the rain, leading to years of erosion and polluted runoff. A study published this month in the Proceedings of the National Academy of Sciences https://www.pnas.org/content/119/10/e2114069119 warns that disasters such as flooding and landslides are increasing in burned areas of the western United States.
Fort Collins also has a reservoir, so losing some water from the Poudre water supply is not an immediate crisis.
Workers have been building permanent structures at a cost of about $300,000 to stop fire debris from entering the water treatment plant, said Mark Kempton, interim deputy director of water resources and treatment at the Fort Collins utility.
Debris from the 2020 fires is expected to take years to clear, and with climate change, wildfires are becoming more frequent and more destructive.
In the future, Kempton said, we could see “fire response become part of routine water additions.”