Power Switch: Economics Driving New Energy for Moving Water

By Warren Tenney

In 2009, I was a new member of the Board overseeing the Central Arizona Project (CAP) and energy, not water, was the primary focus. I was surprised with my sudden immersion into the ins and outs of energy. Yet, there was a good reason for concentrating on energy.

As one of the largest energy users in the state, energy is crucial for CAP. CAP needs to pump water uphill from the Colorado River through the 336-mile canal that delivers water to cities, Native American communities, and farmers in Central Arizona and south to Tucson. Since the 1970s, nearly 90 percent of CAP’s primary energy source has been the Navajo Generating Station (NGS) in Page, Arizona near the Utah border. The plant is one of the country’s largest coal-fired power plants.


So in 2009 and 2010, the U.S. Environmental Protection Agency pushed hard to reduce the haze NGS produced in the scenic Four Corners area. It was estimated that NGS would need over a billion dollars in capital investment to reduce nitrogen oxide emissions to EPA’s satisfaction. Many felt EPA’s unspoken aim was to shut down NGS. CAP and the Salt River Project (SRP), the operator and part owner of the plant, took this attack on NGS seriously.

It was frightening to think of NGS shutting down or being forced to take on huge capital costs to meet EPA’s regulatory demands. The rallying cry was that NGS was critical to make sure CAP had power to operate and to keep energy costs low. At the time, many prominent voices correctly observed that keeping NGS open was important to Arizona’s economy, particularly to the City of Page and the surrounding Navajo Nation. NGS also provided CAP with a key revenue source. CAP sells surplus energy produced by the plant and uses the revenue to repay the federal government the loan it made to finance the construction of the CAP.

A concerted effort was made to find a compromise that EPA would accept to keep NGS open until 2044.  To the relief of many, in July 2014 the EPA and owners of NGS reached an agreement that would lower the levels of nitrogen oxide emission and keep NGS open until 2044.


Inside the Navajo Generating Station  Photos: CAP

So fast-forward three years to today.  Many of us who followed the NGS story since 2009 are surprised with the news that the owners of NGS voted to close the power plant at the end of 2019. What has caused the 180-degree turn in the effort to save NGS?

Pure economics is driving the decision. The utilities that own NGS now are dealing with a power plant that is significantly more expensive than other energy options. Natural gas prices have dropped to record lows to become a viable long-term and economical alternative to coal power. This means pursuing the regulatory upgrades that were part of the compromise with EPA are even less cost-effective today. However, even if EPA loosened its coal regulations, the energy industry is headed towards having natural gas generation as the fuel of choice for many years to come.

So what does this mean to Arizona and particularly the Valley cities that utilize CAP?

First and foremost, CAP will have access to the energy necessary to move water through the CAP system even without NGS. In recent years, CAP has been looking at alternatives to NGS to be prepared for what is now happening. CAP can easily buy energy from the open-market power grid. Based on today’s energy market, CAP’s power costs would actually be significantly lower. Energy costs on the open market are much less than the cost to generate power at the NGS. This means CAP’s pumping energy rate – charged to the Phoenix area cities and others CAP users – will decrease.  Again, this new economic reality of the energy market is much different than just seven years ago when we were worried that an NGS closure would mean higher costs for CAP and its customers. 

NGS has been a reliable energy source for CAP.  While going on the open energy market will mean lower costs today, CAP faces the new challenge of how to best utilize the right energy sources to take advantage of low-cost power alternatives.


Central Arizona Project canal.

While the decision to close NGS is not the dire situation we assumed it would be in 2009 and 2010, the closure of NGS still remains an enormous challenge for the Navajo Nation, Hopi Tribe and the community of Page. NGS has been a primary economic driver and major employer. Assuming the Navajo Nation extends the existing land lease for the plant through the end of 2019, the plant’s owners should have time to explore ideas to lessen the negative impact to that region.

The decision of the utility owners to close NGS – and the challenges it creates – reemphasizes the critical nexus between water and energy.

Warren Tenney was elected twice to serve as a member of the Central Arizona Project (also called the Central Arizona Water Conservation District or CAWCD) Board from Pima County. He served as Vice-President of the Board and as Chairman of the Board’s Finance, Audit & Power Committee. He resigned his board position in January 2016 to become Arizona Municipal Water User Association’s executive director.

For 48 years, Arizona Municipal Water Users Association has worked to protect our member cities’ ability to provide assured, safe and sustainable water supplies to their communities. For more water information visit www.amwua.org

Drought: Five Things You Need To Know About This Rainy Winter

By Warren Tenney

Many people are wondering what this rainy, snowy winter means for Arizona after more than two decades of drought. Here are five things we know right now.

1. It’s raining and snowing in the right places. So far, it has been raining and snowing in locations that have the potential to increase water in two major reservoirs, Roosevelt Lake and Lake Mead. These reservoirs are key to drinking water supplies for the majority of Arizona’s population.

  • Lake Mead relies on runoff from snow pack in the Upper Colorado River Basin, primarily from two main tributaries: the Green River in southwestern Wyoming and the Upper Colorado River in western Colorado. December snowpack in the Colorado River Basin has ranged from 50 percent to three times above normal.  The result of this above normal precipitation will likely boost the reservoir levels of Lake Mead.
  • Roosevelt Lake relies on rain and snow in the watershed that feeds the Salt River. This watershed reaches into the high country northeast of Phoenix. So far, the watershed has received about 45 percent more precipitation than normal. As of January 25th, 211,000 acre-feet of water had flowed into Roosevelt Lake. (One acre-foot of water is enough to serve three average Arizona households for a year.)

2. This is a good start. Weather in February and March must remain cold and wet to hold and increase the gains and potential gains in both reservoirs. Water resource managers are pleased with rain but prefer snow accompanied by extended weeks of cold temperatures. Low temperatures keep the snow on the ground longer, which stops the water in the ground from evaporating and helps to reduce the threat of summer wildfires. The slow flow from melting snow also delivers cleaner water and is easier to manage in a water delivery system. So while it has already been a good winter, we will have to wait until April to know if it has been a great season.


This is a map of the  watershed where the springs, creeks and rivers originate that feed into Roosevelt Lake, a key drinking water reservoir for the Phoenix Metro area.

3. The drought is not over. Research shows that drought cycles and wet cycles in Arizona run 20 to 30 years. A drought cycle has fewer wet years than dry and a wet cycle has a greater number of above average rainy years. The current record-breaking drought cycle began around 1996. The last six years have been the driest on record in the Salt and Verde rivers’ watersheds. If the weather follows historical trends, the current drought could be coming to a close within the next several years, but there’s no certainty and it does not factor in climate change. It would take a few years of greater than average snow and rain to begin to heal the wounds left by the current drought. This includes helping to replenish local aquifers used to back up water available in dams and reservoirs. Plus, two or three years of well above-average precipitation on the watersheds that feed the Salt and Verde rivers would help to re-establish depleted wildlife, such as quail and deer. That much precipitation would help to restore overgrazed grasslands and begin to create a healthier forest, with trees not as susceptible to diseases and bark beetle infestation.


4. AMWUA cities are built for drought. Sunshine is the norm in Central Arizona and rain is an event. We have never denied that we live in an arid part of the country and we plan for drought cycles. AMWUA cities save water underground for future use, keep leaks within their water distribution systems to some of the lowest rates in the country, and re-use 99 percent of their wastewater. Salt River Project (SRP) operates the system of reservoirs and canals that store water from the Salt and Verde rivers. After a rare rainy year in 2010, SRP has faced six dry years on the rivers’ watersheds. Despite record low precipitation, Roosevelt Lake has remained half full and SRP has been able to fill water orders for farmers, industries and cities. SRP was forced to limit water orders by 33 percent in 2002, the driest year in the Southwest in 1,200 years. That year, the SRP system was only 25 percent full and Roosevelt Lake alone was down to 10 percent full. It was the first reduction since the 1950s.

Central Arizona Project (CAP) operates the canal that brings Colorado River water released from Lake Mead to Arizona. CAP has not yet had to reduce water supplies due to a Colorado River shortage. The state’s cities, farmers and industries currently are working together to maintain and increase the level of water stored in Lake Mead and prevent a water shortage declaration next year. The recent increase in winter precipitation and snowpack in the Colorado River Basin decreases the chances that a shortage would be declared in 2018. So, while we regularly face metrological droughts, our water supply droughts are rare.

5. You can make the rain count. Homeowners, apartment managers and businesses make a contribution to our reservoirs when they turn off their irrigation systems and auto-fills on their pools each time it rains. More homeowners and communities also are harvesting the rain by contouring their landscapes to hold storm runoff. Swales built around trees and plants help rainwater stay in place longer so the water soaks deep into the landscape and stays available to plants and trees longer. All of this reduces the need to irrigate and the demand on city water supplies, which in turn saves more drinking water for drinking.

For 48 years, Arizona Municipal Water Users Association has worked to protect our member cities’ ability to provide assured, safe and sustainable water supplies to their communities. For more water information visit http://www.amwua.org. 


AMWUA: Preparing For 2017 By Looking At 2016 Successes

By Warren Tenney

Like you, AMWUA and its member cities already are working toward 2017 goals. At the same time, we’re reviewing what went right in 2016. A look back provides a boost of confidence for us and we hope it will encourage you to get involved and help find ways to solve new and lingering water challenges. Here are a few examples of AMWUA’s work in 2016.


Phoenix Councilwoman Thelda Williams,  AMWUA Board President, called the forum to order.

Legislature: AMWUA helped raise awareness about two state Senate bills that threatened to weaken Arizona’s requirement that new developments have a 100-year adequate water supply before building. Governor Doug Ducey ultimately decided to veto the bills. We also helped to stop or modify other bills that would have threatened the ability of our cities to deliver safe, reliable water. Just last month, AMWUA hosted a forum to inform lawmakers about current water issues and to explain the critical link between sound water policy and Arizona’s economic future.

Financing: In September, AMWUA partnered with the national Alliance for Water Efficiency to host a workshop that provided technical resources to help cities and private utilities develop and implement reasonable water rates. Reasonable water rates are fair to the customer, cover the cost of operating water and sewer systems, and promote conservation. In addition, AMWUA encouraged and participated in discussions to analyze financial issues impacting the Central Arizona Project (CAP) . CAP operates the 360-mile canal that delivers Colorado River water to Arizona cities. Understanding CAP’s finances helps the AMWUA cities prepare for future challenges that could affect the cost of Colorado River water they deliver to their citizens and businesses.

Tonopah Recharge 28

Tonopah Desert Recharge Project Photo: CAP by Philip A. Fortnam

Research and Analysis: In 2016, AMWUA provided cities and their partners with practical and useful research outlining immediate water issues, such as recovering and distributing the water that Arizona has banked in underground aquifers. AMWUA also acted as the eyes and ears for our cities and kept them informed about current and pending water issues. You’ll find AMWUA staff at every major water meeting, such as CAP Board and Committee meetings, Salt River Project (SRP) Board meetings and the Groundwater Users Advisory Committee. I also serve on Governor Ducey’s Water Augmentation Council. We’re working to make sure the state has the water it needs to serve its cities, small towns, agriculture and industries well into the future.

Drought: The biggest ongoing topic among our city members – and all Arizona water professionals – for 2016, for 2017 and beyond is how Arizona can best respond to ongoing drought. The drought is affecting flows in the Colorado, Verde and Salt rivers, which supply the majority of Arizona’s residents with drinking water. Collaboration is the key to keeping our rivers healthy and our supplies reliable. In 2016, AMWUA regularly brought the cities’ water resource managers and water conservation professionals together with Arizona Department of Water Resources, CAP and SRP staff members to share information, challenges and ideas for solutions.

Conservation: In 2016, AMWUA’s assistant director joined the Board of the Alliance for Water Efficiency, which advocates for the efficient and sustainable use of water throughout North America. AMWUA’s Board of Directors also adopted a resolution to support exempting conservation rebates from federal income tax, just as energy rebates are exempt. AMWUA sought help from Arizona’s congressional delegation, encouraged Arizona communities to join the effort, and coordinated with the national coalition working to address the issue. AMWUA also updated its Xeriscape: Landscaping with Style Guide and provided copies to its members to distribute within their communities. 

Partnerships: If anyone knows the benefits of collaborating to solve problems, it’s a 47-year-old organization that helps 10 cities work together to assure a safe and reliable water supply. That’s why AMWUA spent 2016 continuing to build strong relationships with the Legislature, the Governor’s Office, the Arizona Chamber of Commerce and Industry, the Greater Phoenix Economic Council, The Nature Conservancy, the AgriBusiness and Water Council, the Environmental Protection Agency’s WaterSense Program and many others.

img_8063You may know us best through this AMWUA Blog. Our readership is growing every year. We have spent much of 2016 working on a new website that will premier in 2017. Throughout 2016 we continued to keep you informed about regional, state and city water news through our Facebook and Twitter pages. In September, we also started having fun on Instagram, where we share water facts and useful tips with pretty – and not so pretty – pictures. Come take a look at amwua.arizona, #conservationculture.

So, 2017 is going to be an interesting year for water. We’re hoping you’ll join us and use your voice to ensure safe, reliable water supplies remain at the forefront of policy decisions. We want our children and grandchildren to raise their families in a thriving state.

For 48 years, Arizona Municipal Water Users Association has worked to protect our member cities’ ability to provide assured, safe and sustainable water supplies to their communities. For more water information visit www.amwua.org.


Lawmakers Get Answer To Arizona’s Biggest Water Question

By Warren Tenney

When I meet people and they find out I work in water, they always ask me this question: When are we going to run out of water? Arizona legislators – particularly those who were just elected – have the same concerns and questions about the state’s water supplies. Many of these lawmakers from both urban and rural communities attended AMWUA’s legislative forum on December 7th to get answers. AMWUA assembled leaders from the Arizona Department of Water Resources, Central Arizona Project, Salt River Project and the Arizona Chamber of Commerce and Industry to make sure legislators have the latest and best information. Here’s some of what the legislators learned.


The crowd begins to gather at the Desert Botanical Garden for the AMWUA legislative forum.

Arizona is one of the most successful states in the country at managing its water resources. We have never shied away from the fact that we live in an arid place.  Since our water supply is limited, out of necessity we have managed it very well by wringing out every drop. Despite a 17-year drought, Arizona is not in a water crisis and the state has planned for extended drought. Much of the credit goes to Arizona’s forward-thinking leaders who passed the 1980 Arizona Groundwater Management Act. Among other things, this law regulates wells in the state’s most populous areas, requires a 100-year assured water supply before development, and helps to save water in the state’s aquifers for the future. The Act also motivated AMWUA to create a regional water conservation program.  As a result of this regional effort and municipal water conservation programs, water demand in the Valley is the same today as the late 1980s despite a rapid increase in population. AMWUA member cities want to ensure the strong foundation built by the Groundwater Management Act is always strengthened by new legislation and never—intentionally or unintentionally—weakened.


I talk with City of Phoenix Councilwoman Thelda Williams, president of AMWUA’s Board, who called the forum to order.

Despite our successes, there are challenges ahead for us to overcome. Valley cities are supplied mainly with water from the Colorado, Salt and Verde rivers. These rivers are experiencing drought that is affecting state water supplies. For example, flows in the Salt and Verde rivers are down by 35 percent. The rivers are suffering from over-pumping in rural areas not regulated by the Groundwater Management Act and from catastrophic wildfires in overgrown forests where the rivers’ originate.  Furthermore, the AMWUA cities also receive almost 40 percent of their water from Lake Mead, a reservoir behind Hoover Dam on the Colorado River. The water level in Lake Mead determines if and when the U.S. Secretary of the Interior will declare an official Colorado River water shortage. Without continued conservation efforts, there is a 50 percent chance of a shortage declaration in 2018, which would reduce Arizona’s available supply.


Arizona Chamber’s Glenn Hamer said water is a top issue for the Chamber.

At the forum, the Director of the Arizona Department of Water Resources, Thomas Buschatzke, assured legislators the state is working with cities, farmers, industries and Native American communities to reach an agreement to keep more water in Lake Mead and prevent a shortage declaration. If a comprehensive agreement can be reached in time, Director Buschatzke said he would present the plan to state lawmakers for their approval during the 2017 legislative session. A successful Arizona plan is key to Nevada and California agreeing to plans that would protect Lake Mead on a larger scale.

Arizona Chamber CEO Glenn Hamer told lawmakers that he supports Director Buschatzke’s efforts. He also called for the same kind of arduous negotiations and political will that created the 1980 Groundwater Management Act—this time to create a plan that protects our current water supplies in all three rivers.

“We may be at the point where we’re going to have to come together in a bipartisan fashion to protect the state,” Mr. Hamer told the forum. He named water as one of the Chamber’s top three issues. “Water security means economic security,” Mr. Hamer said.

The AMWUA cities have worked hard to help Arizona remain a leader in water management. As a result, the Valley has grown from a dusty outpost into a major economic growth center. But wise water management isn’t just for the AMWUA cities.  Water is a statewide concern.  Rivers and aquifers do not recognize political boundaries. What happens in one part of the state can have a ripple effect in other parts. We are in this together, whether we reside in urban or rural Arizona and whatever our political affiliations.

So here’s the answer to that pervasive question from all water users, whether or not they have the power to make laws. When will Arizona run out of water? We will run out of water when we stop planning, managing, and investing in it.

For 47 years, Arizona Municipal Water Users Association has worked to protect our member cities’ ability to provide assured, safe and sustainable water supplies to their communities. For more water information visit www.amwua.org.

Salt and Verde: Protecting The Valley’s Water Supply

By Warren Tenney

The Salt and Verde rivers are two of the hardest working rivers in the United States.Traveling through Arizona’s northern high country and onto the desert plains, the Salt and Verde provide more than half of the AMWUA cities’ water supply. On November 15th, Phoenix Mayor Greg Stanton and Clarkdale Mayor Doug Van Gausig convened a meeting of mayors, councilmembers, city staffs and business leaders from Central and Northern Arizona to discuss how to keep the Salt and Verde healthy for the benefit of all their communities. This is another example of collaborative efforts to protect the rivers from the threats of fire and drought.


Thanks to the foresight of Valley landowners that formed the Salt River Project (SRP), the Salt and Verde rivers flow into SRP’s system of man-made lakes and reservoirs.  Water from the Salt and Verde is then distributed to homes and businesses in the Phoenix Metro area through canals operated by SRP.


Communities, businesses and environmental groups recognize that the forests, tributaries and groundwater that feed the Salt and Verde rivers are in the midst of a 20-year drought and water flowing in the two rivers has decreased by 35 percent. In the last 15 years, raging wildfires also have burned nearly 2 million acres of northern Arizona’s forests, where waters that keep the rivers flowing originate. These catastrophic wildfires cost the state hundreds of millions of dollars in fire suppression and economic development. Wildfires also leave behind a thick layer of sterile soil that washes into the Salt and Verde rivers and settles into reservoirs. The sediment makes the water delivered by SRP more difficult and expensive for cities to treat for drinking water.

Prescribed burn in Coconino National Forest

The first collaborative effort to address the stresses placed on the Salt and Verde rivers is the Northern Arizona Forest Fund.  Several AMWUA cities are contributing to the Forest Fund, which was spearheaded by SRP. The money is spent on forest thinning projects to protect the watershed.

Now the environmental group The Nature Conservancy has joined the effort to keep more water in the Salt and Verde rivers and ensure the quality and quantity of the Phoenix Metro area’s water supply. The Salt and Verde Rivers Water Fund aims to raise $7 million in the next three years to fund projects that protect these rivers for the communities in the Verde Valley and in the Phoenix Valley.  These projects include helping farmers along the rivers change to less water-intensive crops and to pay for automatic gates to make aging irrigation systems more efficient. The gates allow farmers to electronically control irrigation gates so just the right amount of water flows into irrigation channels to ensure crops thrive. Other projects under the Salt and Verde Rivers Water Fund could include thinning the forests to reduce the likelihood of catastrophic wildfires and protect the watershed.

Like any successful water management plan the new Water Fund relies on collaboration. At the meeting on November 15th, leaders from both the Valley and Northern Arizona discussed the state of the Salt and Verde, as well as how the Salt and Verde Rivers Water Fund could benefit users in both regions of the state. The meeting produced three key takeaways:

  • Your elected officials and cites are deeply engaged in water issues. This includes working with other leaders throughout the state to find innovate water solutions to our water challenges.
  • Initiatives such as the Water Fund show that unlike many of the battles of the past for precious water supplies, both urban and rural communities can find ways to come together to work on improving water security for all.
  • Although the Nature Conservancy has implemented pilot projects to demonstrate the range of possibilities for the Water Fund, the initiative is still in the planning stages. Ultimately, individual cities and communities must evaluate whether the goals of the Water Fund work for their citizens, businesses and communities.

The Salt and Verde Rivers Water Fund along with the Northern Arizona Forest Fund provide new avenues for cities in the Phoenix Valley and the Verde Valley to partner with environmental groups, businesses and farmers to protect and enhance Arizona’s water supplies at the source—high in Arizona’s forests and along its precious rivers.

For 47 years, Arizona Municipal Water Users Association has worked to protect our member cities’ ability to provide assured, safe and sustainable water supplies to their communities. For more water information visit www.amwua.org.

Safe-yield: A Balancing Act For Arizona’s Aquifers

By Warren Tenney

The goal of safe-yield has motivated Arizona’s cities to maximize their use of renewable water supplies – such as river water or recycled wastewater – and to minimize pumping groundwater. Safe-yield means the amount of water pumped out of the ground is the same as what goes back into underground aquifers. The efforts of Arizona’s cities to use renewable supplies and to protect groundwater have helped the Phoenix metropolitan area to weather a 16-year drought.  It is also why we are able to sustain long-term economic strength and enjoy our desert lifestyle.  Arizona’s innovative groundwater law—known as the Groundwater Management Act of 1980—designated safe-yield as a goal for the Phoenix Metro area. 

Groundwater is rain and snowmelt that has settled over thousands of years between rocks and gravel beneath the surface of the Earth.  Groundwater that settles in aquifers is a finite source of water.  Before 1980, uncontrolled pumping was depleting central Arizona’s groundwater, resulting in a lower water table, fissures in the ground, and cracked building foundations.  The Groundwater Management Act required farmers and cities to stop the unsustainable pumping of groundwater and encouraged them to use more water from the Colorado, Salt and Verde Rivers. Today only about 7 to 10 percent of the water used by AMWUA cities is made up of groundwater.

To help meet the safe-yield goal of the Phoenix area, cities financed the construction of treatment plants and other infrastructure necessary to use river water and recycled wastewater. Cities also have invested in storing water underground to meet and sustain safe-yield.

How To Recharge An Aquifer

Storing water underground is known as “recharging” the aquifer. Cities recharge water for at least two purposes: (1) to build up a bank account of water underground for times of drought, and (2) to offset groundwater that a city pumps and delivers to businesses and citizens. There are several ways to recharge or store water in an aquifer. Here are a few.

  • Recharge Wells: Cities build two main types of wells to recharge water into an aquifer. The first is a well dug 150 to 200 feet into the ground to direct water back into the aquifer. These are called “vadose zone wells” because they are sunk through the vadose zone or the upper part of the aquifer. The second type of well is called an “aquifer storage and recovery well” or ASR. This is a deeper well that goes 600 to 1,000 feet into the middle of the aquifer. These wells allow cities to both pump water directly back into the aquifer and pull it back out when needed.


    A vadose zone well in Scottsdale.

  • Recharge Basins: Some cities create basins filled with recycled wastewater or river water. The basins are built to help the water easily percolate back into the ground. These are known as recharge basins. Recharge basins come in a variety of sizes, from large regional facilities that allow multiple entities to store water at one location, to smaller recharge basins often owned by individual cities. Some cities create recharge basins on the site of their treatment plants, while others turn portions of them into recreational areas. For example, the Town of Gilbert turned some of its recharge basins into a 110-acre wildlife habitat called the Riparian Preserve at Water Ranch, located near Guadalupe and Greenfield roads.
  • Managed Recharge: Some cities receive permits to discharge river water into normally dry streambeds, where the water filters back into the aquifer.

    "Aerial shots of GRUSP"

    Granite Reef Underground Storage Project is a regional storage facility. PHOTO: Salt River Project

How Cities Make It Happen

Like many Valley cities, the City of Scottsdale recharges water into its aquifers as part of its commitment to contribute to the region’s goal of safe-yield. The City recharges most of this water within the city limits through vadose and ASR wells, and it also recharges water at regional recharge basins owned by Salt River Project and the Central Arizona Project.

Along with water from the Salt and Verde Rivers delivered by SRP, Scottsdale receives water from the Colorado River through the Central Arizona Project (CAP). Each October, Scottsdale Water places an order for its annual allotment of 80,000 acre-feet of Colorado River water with Central Arizona Project. One acre-foot of water serves an average of three Arizona families for a year.  Scottsdale’s current demand for Colorado River water is about 60,000 acre-feet per year. This leaves 20,000 acre-feet available to store.

Scottsdale sends the remaining 20,000 acre-feet of Colorado River water to one of two regional recharge facilities in Maricopa County. These recharge facilities provide two advantages. First, the facilities allow the city to return the water to the aquifer, which allows Scottsdale to do its part towards the safe-yield goal for the Phoenix metro area. Second, it allows the city to store or bank additional water it doesn’t need immediately for future use.  

The state’s water agency, Arizona Department of Water Resources, tracks the amount of water each city pumps out and recharges back into the ground. The agency does this to monitor if a city is contributing to the regional goal of safe-yield. The Department also tracks the amount of water each city returns to the aquifer as storage and gives the city a “long-term storage credit” for each acre-foot it stores, minus a 5 percent donation to the aquifer. This will allow cities to withdraw the correct amount of water when it is needed. 

What It Means To You

In 1980, wells in Maricopa, Pinal and Pima counties pumped out 2.3 million acre-feet more groundwater than could be recharged naturally. In 2013, the groundwater overdraft in Maricopa, Pinal and Pima counties had been reduced to about 382,000 acre-feet due to the Groundwater Management Act, including efforts to reach safe-yield.

The Groundwater Management Act only applies to the state’s five most populated areas called Active Management Areas. In recent years, the Phoenix Active Management Area has met its safe-yield goal.  The challenge is to continue to sustain safe-yield and ensure we have water to meet our future demand.  AMWUA cities will continue to seek and promote solutions to ensure that central Arizona achieves safe-yield to protect our most valuable resource—water.

For 46 years, Arizona Municipal Water Users Association has worked to protect our member cities’ ability to provide assured, safe and sustainable water supplies to their communities. For more water information visit www.amwua.org.



















Salt River: Bringing Life To A Desert Valley

By Warren Tenney

A likely shortage of Colorado River water in Arizona is big news. It should be. Colorado River water makes up 44 percent of the state’s water supply delivered through 336-miles of canals and pumps known as the Central Arizona Project. Colorado River water is important to Arizona but it is not the state’s only source of drinking water.

Salt River Project (SRP) operates eight dams, seven reservoirs and 131 miles of canals that bring water from the Salt and Verde rivers to the Phoenix metropolitan area. SRP provides 12 percent of Arizona’s water and is the largest provider of water to the Phoenix Metropolitan area.

A Short History

The Salt River has served the Valley since the ancient Hohokam people settled here in the year 300 A.D. These Native Americans built a 500-mile canal system that brought river water into their villages and fields for the next 1,000 years. They vanished around 1450.

The Hohokam had been gone nearly 400 years when an 1860s gold rush attracted fortune seekers to the Salt River Valley. Among them was Jack Swilling, an ex-Confederate cavalryman, who saw an opportunity to use water from the Salt River via canals to grow crops. He sold those crops to miners and the U.S. Calvary stationed at Fort McDowell.

Individuals, private companies, and associations started digging dozens of ditches trying to replicate Swilling’s success. The luckiest of these ventures lasted 30 years. Then came the same natural phenomenon that historians suspect pushed the Hohokam from the Valley: drought. The Salt River could no longer provide enough water for all the canals and thousands of acres of crops withered. Like the Hohokam, hundreds of pioneers left the desert village. 


To thrive, Phoenix needed a dam that would collect and store river water in the mountains to the north and east. The 1902 National Reclamation Act provided Phoenix with federal loans to build two dams on the Salt River, Theodore Roosevelt and Granite Reef Diversion. The federal government also bought out the ditch companies and connected all the canals into one system.

Ranchers and farmers who had remained in the Salt River Valley organized the Salt River Water Users’ Association and pledged their lands as collateral for the federal loans. In 1917, the federal government turned over the operation of the canal system to the Salt River Valley Water Users’ Association, which continues to operate the canals for the federal government as the Salt River Project.

Roosevelt Dam provides both a reservoir and hydropower. The Roosevelt Dam began supplying hydroelectric power to a copper mine in 1912. To increase its power capacity, SRP built three more dams along the Salt River before 1930. By 1946, SRP had built two dams on the Verde River. (These dams do not generate hydropower.)

After World War II the Salt River Valley was rapidly turning into an urban center that needed water for residential customers, rather than solely ranchers and farmers. In 1952, the City of Phoenix established the first contract with SRP to divert water from its canals to treat and deliver to homes. By 1984, SRP was delivering 55 percent of its water to Valley cities.

How It Works

The Salt and Verde rivers flow into Roosevelt Lake behind Roosevelt Dam. The reservoir can hold 1.6 million acre-feet or enough to meet SRP contracts for two years.

Canyon Lake

Canyon Lake

  • The water then runs through three reservoirs that are popular recreation lakes for Valley residents: Apache, Canyon and Saguaro. The Verde River water flows through Horseshoe and Bartlett lakes.
  • The water is released back into the Salt and Verde rivers, which eventually converge behind the Granite Reef Diversion Dam east of Mesa.
  • From there the river water enters into the Valley’s familiar canal system via gravity and is distributed to city water treatment plants and to farms.

SRP serves water to a 375-square-mile area and electricity to more than 1 million customers. The total SRP system today is about 55 percent full – just about the same as one year ago. In this 16th year of drought, the January-to-May snowmelt into the Salt and Verde rivers was below the median flow for the sixth consecutive year. The bright spot? The Phoenix metropolitan area has reduced its demand for water over the last 20 years.

What It Means To You

The Salt River and the Colorado River provide the AMWUA cities with a robust water supply. SRP makes up 53 percent of the water portfolio for the 10 largest cities in Maricopa County.  Having more than one source of water means a stronger economy for the Valley and a more reliable source of water for you.

SRP is unique to Arizona. We are all stewards of the Salt and Verde rivers. The watershed and forests that created and nurture these water sources must be managed well. We all have a responsibility to protect our watershed and forests, whether through making certain our actions do not cause a fire when camping or getting involved in forest restoration efforts. The health of our forests impacts the quality and sustainability of our water. 

Want to learn more about Salt River Project? Here’s a great place to begin.

For 46 years, Arizona Municipal Water Users Association has worked to protect our member cities’ ability to provide assured, safe and sustainable water supplies to their communities. For more water information visit www.amwua.org.