An Eye on Every Drop

By Douglas Frost, AICP

Many Americans, and even Arizona residents, have incomplete, exaggerated, or even totally incorrect assumptions about the urban water infrastructure and supply situation in Metropolitan Phoenix.

Many believe that because urban development has been strong here for decades, and because much of Arizona's land is desert, its cities depend largely on groundwater.

In fact, groundwater makes up only about two percent of the total water supply for Phoenix, and its supply portfolio can accommodate new growth for decades to come. Not all of the state's municipalities have such robust water supplies, but it is important to understand that Arizona's situation can in many ways be considered a success story.

Many people also have the misconception that the Valley of the Sun's urban development is unsustainable, either because a tremendous amount of water is "wasted" or a short-term, consumption-focused philosophy is pervasive. The reality is far more nuanced.

It's true that in the past, per capita water usage was high, and new homes were built with grass lawns, pools, and inefficient fixtures and appliances at a breakneck speed. Planners responded by repeatedly seeking additional supplies to meet the demand. However, over the past three decades, a revolution has occurred in the way residents use water.

A glance at total water production at the city's treatment plants is one way to demonstrate that shift. In 1996, 320,288 acre-feet of water was treated, compared to just 299,317 AF of water in 2014 — even though nearly 360,000 new residents and numerous businesses were added. That means that over this period, despite population increases in the city of Phoenix in the last 20 years, total water use actually decreased significantly.

The larger metro area has seen a similar trend. While the population grew from 2.63 to 3.96 million between 1996 and 2013, an increase of 50 percent, water use increased only by 24 percent. And depending on one's definition of "wasted" water, Phoenix is quite efficient with its sewage. Virtually everything treated at the city's wastewater plants is used again for cooling at power generation plants, agricultural irrigation, or environmental projects.

Water infrastructure

Not until federal government and community efforts to construct massive dam and canal structures, between 1910 and 1990, did urban Arizona have the water supplies to accommodate the tremendous growth that occurred when air conditioning, air travel, and the new interstate highway system spurred rapid urban development in the second half of the 20th century.

The first major dam, the Roosevelt Dam, was built in 1911. Farm owners back then had the foresight to mortgage their land to obtain federal funds to build a series of facilities that eventually came to be the Salt River Project. Horse Mesa Dam, Bartlett Dam, and Horseshoe Dam were built in the decades that followed, for the storage and distribution of Salt River and Verde River water.

Today, the SRP provides water to the Phoenix, Mesa, Tempe, Scottsdale, Chandler, and Glendale water utilities, and is a key entity in the management of water supply operations in the state. All told, the system delivered an average of 666,244 AF of water per year between 2012 and 2014, with Phoenix using 169,905 AF a year and other municipalities using 193,254 AF (on average) during that time period. The remainder went to agriculture.

Water also comes from the Colorado River, thanks to the Central Arizona Project, a 336-mile-long series of canals and reservoirs serving Central and Southern Arizona that was completed in 1992. The system annually delivers 1.5 million AF of Colorado River water to Central Arizona. CAP was entirely financed and partially funded by the federal government, with municipal utilities and others repaying the remaining debt.

"The rapid expansion of cities in Metropolitan Phoenix only occurred because of a high degree of cooperation between property owners, municipal utilities, the state legislature, local businessmen, and of course, the federal government in funding and financing water projects," says Douglas Kupel, deputy water services director for the city of Glendale and the author of the book Fuel for Growth, a history of Arizona's water and urban development. The SRP and CAP systems have provided a dependable water supply for cities and farms alike, facilitating the area's tremendous urban growth following the Second World War.

While drought and, at times, over-allocation, have affected water supply — together those factors contributed to recent drops in water levels at Lake Mead and Lake Powell — water supplies in Arizona have been relatively stable. That has allowed the state to avoid the dire shortages experienced in California, Texas, and other parts of the U.S.

An aerial view of a CAP canal snaking through the Phoenix metro area. The CAP system has helped to ensure a dependable water supply for the region since its completion in 1992. Photo by Pete McBride/National Geographic Creative.

More people, less water use

Starting around mid-century, many high-tech firms like Motorola, Honeywell, and Intel established manufacturing facilities in Phoenix. The city and the Valley, with their reliable water supplies, were seen as attractive alternatives to desirable but expensive locations in California, and the rapid expansion of high-tech and defense firms and an influx of well-paid engineers and skilled workers helped to drive growth. The population of the city of Phoenix exploded after 1950, rising from 107,000 then to 996,501 in 1990 during the age of American mass production and consumption. Today, the population is 1,514,458.

With those jobs came low-density, single-family housing, just as in other parts of the U.S. Virtually all new homes came equipped with indoor plumbing and grass lawns, and until about 1990 the numbers of washing machines, dishwashers, and swimming pools increased at a dramatic pace, which drove up the Valley's water demands and per capita water use.

Water utilities struggled to keep up, continually adding new water and wastewater treatment capacity, building larger networks of water mains and sewers, and seeking out new water supplies. Capital improvement projects consistently commanded a large portion of municipal budgets, and rising demands for services dominated planning considerations until the 21st century.

Urban growth and its thirst for water were so intense by the 1970s that something had to be done. The Arizona Groundwater Management Act of 1980 was a hard-won compromise between municipal, agricultural, and industrial interests to eliminate excessive groundwater pumping. The act establishes specific requirements for each of those water users, among others, with the intent of meeting a goal of "safe yield" — defined as the amount of water that can be withdrawn from an aquifer without significant negative impacts — by 2025 for certain areas of the state, including the Phoenix Active Management Area.

Notable aspects of the law include regulation of water use on farms, levies on groundwater pumping, municipal conservation requirements, elimination of high-water-use landscaping in public rights-of-way, limitations on artificial water features, and restrictions on water use for golf courses and other large turf facilities. Perhaps most importantly, proposals for new development must prove that they have an assured 100-year water supply before approvals will be granted.

Other efforts followed. The state, municipalities, and organizations like the Arizona Municipal Water Users Association began to actively promote the use of native landscaping for homes, businesses, and open space through public campaigns, educational efforts in conjunction with nurseries, and restrictions on the types of plants used in rights-of-way.

The city of Phoenix, spurred on by both wastewater capacity and water supply issues, changed its plumbing code in the 1980s to require more efficient fixtures, established a water conservation office, subsidized the installation of more efficient toilets, and introduced water resource and system impact fees to pay for new facilities and water supplies. These interventions, although not universally popular, ultimately proved to be very successful.

Things were happening on a national level starting about a decade later, in the 1990s. The 1992 Federal Energy Policy Act established plumbing fixture water use standards — most notably limiting toilets to 1.6 gallon per flush — that precipitated a drop in water use rates. Federal programs that work with manufacturers and local government interests to establish efficiency specifications of consumer products — toilets, clothes washers, dishwashers, faucets, showerheads, and other fixtures — first through the Energy Star and then WaterSense labeling programs, continue to result in gradual reductions in indoor residential and commercial water use.

These federal fixture standards, combined with an increasing acceptance of low-water-use landscaping, caused per capita water use to stop growing and actually begin to decline in many Arizona communities. In the mid-1980s, about 20 percent of single family homes in Phoenix had xeriscape (partial or mostly desert) landscaping; by the late 1990s, the proportion had grown to about 50 percent. Today, it is over 80 percent. Arizona home builders, who sometimes resisted early conservation efforts, now routinely construct high-efficiency homes with partial or mostly desert landscapes.

While per capita water use declined slowly in the 1980s and 1990s, changes occurred more rapidly after 2000. That's because commercial and household efficiencies lessened demand at about the same that the economy in the Valley stalled. Major production facilities for defense and high-tech firms stopped moving there in large numbers, and the operations that remained reduced staff, relocated manufacturing operations, or introduced new equipment that used less water. Since 2000, employment growth has shifted toward low-water-use sectors like financial services and software development, further lessening the connection between economic activity and water consumption.

Counterintuitively, the real estate boom that occurred after the turn of the century actually accelerated water efficiency gains. Homes renovated for resale and new residential construction led to the installation of newer, more efficient toilets, washing machines, and xeriscape landscaping. As a result, per capita residential use in Phoenix declined 8.9 percent between 2000 and 2007, significantly more than the 1.9 percent reduction seen during the previous seven years (between 1993 and 2000).

The SRP, another major project, delivers Salt River water. Landscaping, plazas, and the Marshall Way Bridge help make this section of the SRP's Arizona Canal in downtown Scottsdale part of the public realm. "Marshall Way bridge" by Cygnusloop99, wikipedia (CC BY-SA 3.0).

Increased efficiency

The sharp recession that followed further reinforced the shift to increased efficiency. Various industries' production rates slowed, reducing water demand, and companies also saw saving water as a cost-saving measure. Home owners also tightened their belts, reducing water and energy use, and installing desert-oriented landscapes that were less expensive to maintain. Nationally, fixture and other product manufacturers continued to respond to customers' demands for even higher energy and water efficiencies than those mandated by law.

One of the most interesting aspects of the current era, and one which is not often recognized, is the degree to which businesses and households are using less water, electric power, natural gas, and gasoline while maintaining or even increasing the levels of service provided by those commodities. Evidence abounds in the nonresidential sectors:

• As manufacturers replace and update equipment, they are adopting looped systems that reuse both water and energy.
• Hospitals' sterilization processes and digital imagery technologies no longer even use water.
• Schools are introducing artificial turf on playing fields and are installing geothermal cooling systems for air conditioning, which eliminate or reduce the number of water-using cooling towers.
• Commercial laundries use washer extractors that consume just two-thirds the amount of water that devices used 10 years ago.
• Offices and other facilities use far more energy efficient lighting systems, equipment, and air conditioners, which reduces heat loads and in turn lowers the requirements on cooling towers.

As Eddie Wilcut, a 25-year veteran of water conservation efforts in Texas and more recently a consultant in the Phoenix area says: "It is truly surprising how much change is occurring, and has occurred, in the commercial and industrial sectors — they just keep finding more and more ingenious ways to reduce water use."

And then there's the home front. Adding to the shift toward drought-resistant landscaping and water-efficient drip irrigation systems, more developments are being built with community pools and fewer new homes are equipped with backyard pools. Pool construction reached its peak in the early 1990s, and homes built in 1993 have the highest proportion of units with pools — 50 percent. Only about a fifth of homes built from 2005 to 2015 have pools. Inside the home, devices are becoming increasingly more efficient. Take washing machines: Water use per cycle dropped from about 50 gallons in the 1980s to about 40 gallons in the 1990s and today, some top-load washers use just 18 gallons per load while the latest front loaders use as little 12 to 14 gallons.

 In the 1970s most new developments had turf-dominated landscapes that required large amounts of water for irrigation. Now most new housing developments have mostly or partially desert landscapes. Many that are located in the north, like Fireside at Norterra, are designed to resemble nearby hills and mountains. Source: Phoenix Water Services.

Planning implications

Municipal utilities in the Valley are thus faced with a complicated set of planning challenges. Each has its own portfolio of existing and future supplies, its own customer use profiles, and its own rate of change patterns, which can defy easy quantification.

In Arizona, like most of the West, water is generally allocated on the basis of prior rights, and communities like Phoenix, Mesa, Tempe, and Glendale were able to obtain relatively good allocations of water from the SRP and CAP systems prior to 1990. As a result, the utilities in these jurisdictions will be able to obtain substantial supplies even if cuts are made in those systems in periods of shortage.

Most of those older, established cities also have a large base of housing stock built before 1995, when units were less efficient, and as a result have a "reservoir" of future demand reductions associated with gradual upgrades that will go on for decades.

Newer communities are more vulnerable. Their housing stock is newer and more efficient, and thus less able to reduce use in coming decades, and because those communities were established after most surface water in Arizona was already allocated, their access to SRP and CAP supplies is much more limited and more liable to be cut in shortage years.

The region's supply is pretty stable, but Phoenix isn't taking any chances. The city is committed to building a resilient system that can withstand future droughts. With the decline in per capita use, planning has shifted away from adding new supply toward the bolstering of groundwater reserves to deal with the periodic reductions that will almost inevitably occur in CAP and SRP deliveries in coming decades.

Extensive scenario analyses are helping city staff to identify the impacts of varying levels of efficiency gains, population change, and supply variations to ensure that Phoenix will be able to respond to all potential demands on infrastructure and resources.

Over the next decade the city will also be ramping up its efforts to increase, rather than deplete, its groundwater reserves by injecting water into aquifers using special wells. Other communities and state agencies in Arizona have already implemented similar strategies in an effort to add to groundwater resources. Phoenix and Tucson are also working on a cooperative exchange project that would see Phoenix moving water to Tucson for storage in regular years and then reclaiming that water in shortage years.

Still, there's a lot to learn. Arizona utility and land-use planners will have to become more cognizant of the intricacies of water supply and demand issues, abandon old assumptions, undertake more research, and improve coordination between different organizations and professional disciplines.

Here's one of those old assumptions: For years, many planners have said that higher densities would automatically lead to reduced water use. The reality, however, is much more complex. With the widespread use of desert landscaping, owners of single-family homes can have large lots that require little or no irrigation water. On the other hand, research indicates that some multifamily developments maintain lush landscaping that boosts residents' per capita water usage, and many high-rise multifamily complexes have cooling towers that raise usage even more.

Similarly, economic development and lower water use are not necessarily mutually exclusive. While some projects like data warehouses with cooling towers or traditional golf courses can lead to increased demands that may be difficult to justify in communities with limited resources, it must be noted that not all high-quality employment has high water consumption. In part that's because new commercial developments are installing high-efficiency fixtures and equipment, and renovations and upgrades of existing production facilities also typically result in lower water use.

This is not to imply, however, that urban growth in the Valley of the Sun can continue indefinitely without any concern about water resources. Eventually some areas will reach the point where even extremely water-efficient growth cannot be accommodated.

A greater threat, though, is the possibility that Arizonans will become complacent about the need to be efficient. With relatively low water rates by national standards, and few onerous restrictions on use, residents and businesses are being relied on to make responsible decisions without the major interventions common in neighboring states.

One of the most difficult potential scenarios for water planners would be a reversal of the current trend toward desert landscaping. Nonnative plants and turf not only increase peak demands in the summer, stressing infrastructure and depleting supplies on an ongoing basis, they also dramatically increase risk during drought cycles or long-term climatic change; as the climate becomes hot and dry, customers increase their irrigation demands at precisely the worst time — just when basins dry out quickly and supplies rapidly diminish.

If the trend toward efficiency slows, population growth rates increase significantly, or severe shortages occur as a result of droughts (like those experienced in Australia and California), Arizona communities could be forced to take aggressive action as they did in the 1980s. Because obtaining additional water supplies from desalination or other distant sources is so expensive, and because only so much groundwater can be pumped locally on a sustainable basis, the Valley of the Sun is to a large degree working within a given water budget.

As a result, the highly successful but not always recognized initiatives to improve efficiency — undertaken by individual residents, businesses, local communities, water providers, appliance manufacturers, and the state and federal governments alike — will be critical if the area is to continue growing and prospering. To keep those collaborative initiatives moving forward, however, it may first be necessary to better understand the state's past, current, and possible future realities.

Douglas Frost is a principal planner with the Phoenix Water Services Department.

Resources

Central Arizona Project: 30 Years of Shaping Arizona. A vast system of canals, tunnels, pipelines, and pumping stations transports Colorado River water some 330 miles across the desert.http://tinyurl.com/jse2fup

History of Water Management in Arizona. Arizonans have been working with water since the 1860s, when the then-territory established the Howell Code governing appropriations. Follow the flow of water management in this interactive timeline. http://tinyurl.com/zwcyhg5