The desert city of Tucson, Arizona, gets more rainfall each year than its residents use, but pays $80 million to pipe in water from the Colorado River through the Central Arizona Project canal. Brad Lancaster, a nationally recognized rainwater harvesting expert who runs a permaculture consulting firm, doesn’t think this makes much sense.
“It’s insane that we’re still spending so much money to bring lower-quality water from 300 miles (480 km) away when we have this huge amount of water coming free of charge from the sky that we could be using as a primary source,” says the author of Rainwater Harvesting for Drylands and Beyond. “I don’t think we should be using the Colorado River as our checking account.”
And he knows what he’s talking about – both from his own home in Tucson and from study with Zimbabwe’s legendary ‘water man’, who taught so many around the world how to ‘plant water’. “I couldn’t believe he did that with so few resources,” recalls Lancaster. “Phiri showed me what just one person could do.”
The late Zephaniah Phiri Maseko raised a family of eight from a barren plot that he turned into an oasis by capturing rain with a system of basins, swales and stone dams. He was awarded a National Geographic Society/Buffett Award for Leadership in Conservation in 2006 and a Lifetime Achievement Award in 2010 by the University of Zimbabwe.
His innovations came from long and careful observation. Beginning in 1966, he studied rainfall patterns and experimented with terraces, reservoirs, catchments, canals, infiltration pits and fish ponds. His irrigation practices made it possible for subsistence farmers on marginal lands to prosper by retaining scarce rainfall and raising the local water table.
Four years after Zimbabwe gained independence in 1980, Phiri returned to farming, irrigating, and teaching his neighbors. He founded the Vulindhlebe Soil and Water Conservation Project in 1984 and the Zvishavane Water Project in 1986 and spread his knowledge and skills through on-site visits and exchanges with arid-land farming communities throughout southern and eastern Africa.
Once home, Lancaster began putting Phiri’s lesson into practice. And his example has encouraged a paradigm change in Tucson’s water management practices.
He turned his own lot into a pilot site, digging roadside soil beds that he planted with native trees and shrubs. As the trees grew and needed more water, he cut small gaps in street curbs to allow storm water to run off the road and into his sidewalk garden. Diverting stormwater and greywater runoff to the right places, and growing drought-tolerant native plants, can cut outdoor municipal water use to zero, all for “the price of a shovel,” he says.
His own home and neighbourhood is proof of how well this works. While the curb cut wasn’t legal when he did it, the city made the process legal by 2007 and now incorporates it into its storm drainage system. This inspired a broader paradigm shift that has radically transformed how Tucson deals with rainwater, preparing the city for the drying climate that has raised such concerns about the Colorado River.
“As a growing number of towns and municipalities in the western United States and around the world are faced with rapidly dwindling freshwater supplies, experts say Tucson’s rainwater push may hold valuable lessons about how a city can balance the water budget and increase resilience”, BBC’s Future Planet reported in 2022.
It is something the city has been working on for a long time, thanks in part to Lancaster. “The philosophy here had been for decades to treat runoff as a waste,” says Rodney Glassman, a former Tucson councilman who helped spearhead efforts to legalize curb cuts. “What Lancaster’s example made us realize was that stormwater is actually something we can use and benefit from.”
In 2008, Tucson became the first US municipality to require developers of commercial properties to harvest rainwater for landscaping. As of June 1, 2010, new developments were required to meet 50% of their landscaping water requirements by capturing rainwater.
In 2012, Tucson Water began an ambitious incentive program that rebates homeowners up to $2,000 (£1,820) for the purchase of rainwater-collecting equipment such as tanks or landscape design systems that capture rain for indoor and outdoor use. Project Harvest, a collaboration between SERI and the University of Arizona, is studying the chemistry of cistern water with samples from citizen scientists who own rainwater harvesting systems. Through its Limited-Income Rainwater Harvesting Program, the city assists low income residents who cannot afford to install a rainwater harvesting system and maintain trees.
In 2013, Tucson’s Green Streets Policy mandated all publicly funded roadway projects to capture the first half inch of rain during a storm. And with the Green Stormwater Infrastructure of 2020, Tucson began a small surcharge on residents’ water bills to raise about $3m annually to support public stormwater capture projects such as the city’s million-trees initiative.
These measures mean that “whenever we build a road, put up a parking lot, or rip and replace public and private infrastructure, we do it in a way that works with nature to manage stormwater as close to its source as possible,” says Candice Rupprecht, water conservation manager for Tucson Water. The benefits go beyond water conservation, she says, including reducing soil erosion, mitigating street flooding risks, and creating green spaces that cool surfaces and help reduce the urban heat island effect. By 2050, it’s estimated that one-third of Tucson’s days will reach 105 degrees.
Tucson Mayor Regina Romero has just signed a multi-year agreement with the Bureau of Reclamation through the Central Arizona Project, reducing Tucson’s water allocations from the Colorado River by up to 110,000 acre-feet and offering the city compensation of $400 per acre-foot for every unit conserved. The agreement will turn back 50,000 acre-feet of water in Lake Mead this year and critical infrastructure projects to reduce water loss and encourage conservation are on the horizon, says John Kmiec, director of Tucson Water.
While there is a long way to go, the city seems to be doing well thus far. According to the 2021 Tucson’s Water Conservation Report, the rebate program saved 41.9 million gallons (158 million liters) of potable drinking water last year alone. To date, the program has resulted in more than 4.2 billion gallons (15 billion liters) conserved – equal to the amount of water that flows out of the Hudson River’s mouth in New York over nearly seven hours.
Millions lack access to running water. Is the solution hiding in plain sight? Washington Post, Mar. 27, 2023
Tucson’s 1 million trees by 2030 goal getting community boost. Tucson.com, Feb. 7, 2023
How Tucson, Arizona is facing up to a megadrought. BBC Future Planet, Oct. 31, 2022
Tucson passes nation’s first rainwater harvesting ordinance for commercial properties. Center for Biological Diversity, Oct. 16, 2008
The Rainwater Harvester. Muonde Trust, You Tube, Jul. 17, 2013
Water harvesting principles & the story of an African rain farmer. Brad Lancaster, You Tube, Feb. 21, 2017
‘A living pantry’: how an urban food forest in Arizona became a model for climate action. Guardian, Mar. 21, 2023
Cover image: Tucson Clean and Beautiful