Five Things You Need To Know Right Now About Drought

By Warren Tenney

Ongoing headlines about drought in the southwest are confusing and often seem contradictory. Two weeks ago, a panel of experts advised the Governor’s Office that Arizona’s drought is not over and will last, at least, another year. After a rainy winter, that’s a surprise for many people who follow the state’s drought status maps. These monthly drought maps show no portion of Arizona remaining in “extreme” or “severe” drought. Then there is the conundrum created by the decline of Lake Mead, the Colorado River reservoir critical to Arizona’s water supplies. This winter’s heavy snow in the Rocky Mountains of Colorado and Wyoming means Lake Mead will receive enough water to avoid a shortage declaration. Yet, the Lake’s levels remain a source of great concern among water professionals. Oh, and why has California, but not Arizona, declared its drought over?

Here are five questions and the answers you need to know about drought to help you cut through the confusion.

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Here is where to follow Arizona’s monthly drought conditions: http://www.azwater.gov/AzDWR/StatewidePlanning/Drought/DroughtStatus2.htm

1. What is drought?

A drought is not a moment in time. Drought is a cycle. Research shows that drought cycles and wet cycles in Arizona run 20 to 30 years. That’s why you hear water experts say: One rainy winter doesn’t end a drought. One rainy winter can temporarily ease “drought conditions” in some areas of the state. The current drought cycle began around 1996. If rainfall and snowfall continue to be above average over the next several years then Arizona’s climate experts would be more likely to call this drought finished. These same experts say there is a 50 percent chance of that happening. The wild card is climate change.

2. Why is Lake Mead still at worrisome low levels?

Lake Mead is a reservoir that contains Colorado River water behind Hoover Dam. The legal allotments of Lake Mead water given to states and communities outstrip the average amount of Colorado River water entering the Lake. Even without a drought, normal withdrawals of water from Lake Mead would cause it to fall an average of 12 feet every year.  The drought on the Colorado River Basin has exacerbated the situation.  Voluntary efforts by states that depend on Lake Mead have kept it from falling to a level where the federal government would declare a shortage. A shortage declaration would mean less Colorado River water would be delivered to Arizona. It would affect farmers first, but if Lake Mead levels fall farther, Colorado River water supplies to cities would eventually be cut.  So far, the Colorado River has been able to keep delivering, but living on the edge of shortage is unacceptable to water managers. The Arizona Department of Water Resources is working with the state’s cities, Native American communities, farmers and industries to voluntarily cut back on water taken from Mead. Once Arizona reaches an internal agreement it can finish negotiations with California, Nevada and Mexico to voluntarily reduce legal allotments of Colorado River water to match the reality of what the river can supply. Right now, Lake Mead is only 10 feet higher than it was this time last year.

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Lake Mead

3. After 20 years of drought, why are Arizona’s water supplies not critically low?

Drought is a normal occurrence in our arid environment. Central Arizona has built, planned, and managed water supplies to ensure reliability during drought cycles.  Massive reservoirs capture water during wet periods for times when precipitation is scarce. The Arizona Groundwater Act of 1980 requires cities and farmers in the most populated areas of the state to implement conservation programs, protect the groundwater from over pumping and rely on renewable surface (river) water instead. The majority of the state’s water supply comes from the Colorado River via the Central Arizona Project (CAP) and the Salt River via Salt River Project (SRP).  Virtually all wastewater is recycled and put to use, and water is stored underground for use in shortage.  A limited amount of groundwater is pumped from the aquifers for use, as well. Multiple sources of water allow cities to offset reductions in one or more supplies. For example, Arizona’s drought has reduced the amount of water in SRP reservoirs in the mountains east of Phoenix, but SRP has been able to offset possible shortages by pumping from its numerous wells. Arizona law requires Valley cities to offset every acre-foot of groundwater SRP pumps by recharging (or returning water to) the aquifers from their renewable water supplies, such as extra Colorado River water (ordered but not immediately needed) or recycled wastewater. This keeps the Valley’s aquifers in good condition and hedges against shortages.

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Granite Reef Underground Storage Project   Photo: Mark Durben

4. So, if we’re in good shape, do we still need to conserve water?

We live in a desert. Long-term, ongoing conservation efforts are something AMWUA member cities promote tirelessly, and for good reason. Drought is an uncontrollable weather phenomenon and the impact of climate change is unknown. Our groundwater supplies are finite. Once used, aquifers replenish over decades, not years, and usually not to previous capacity. Using less water on a daily basis means leaving more water in the ground and storing more water for a time when river water supplies are short. If shortages were to prevent cities from meeting normal, everyday demands for water, all AMWUA cities, by law, have shortage-preparedness plans ready to go. These plans are designed to incrementally reduce water use to bring demand in line with available supplies while protecting our quality of life and the economy. Despite that, no city wants to declare a water shortage. So for now, keep taking those short showers, keep watering those shade trees efficiently, and keep using water wisely. Your city will let you know when it needs more help.

5. Why is Arizona’s drought continuing while California has declared that its drought is over?

California has declared an end to the drought’s State of Emergency, but that doesn’t mean it is entirely out of the drought that has gripped the state since 2012. Due to the economic impacts of ongoing drought, record low reservoir levels, and snowpack at 20 percent of normal levels, California’s governor declared in January 2014 a State of Emergency. In January 2015, with no end to drought in site, cities and towns across the state were required to reduce water use by 25 percent. Recent record-breaking precipitation freed the northern part of the state from drought and refilled the majority of reservoirs, allowing the state to rescind the mandatory water use reductions and lift the emergency declaration for all but four counties. However, almost half the state remains in severe drought.

Arizona’s current drought began around 1996.  Arizona’s Drought Emergency Declaration has been in effect since June 1999 and still remains in effect. We haven’t yet seen enough wet weather across the state to lift either the drought or the declaration. 

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.

Regional Partnerships Keep Water Affordable

By Warren Tenney

It is not easy for cities to build, staff and operate water and wastewater treatment plants and still maintain water and wastewater rates all residents can afford. That’s why Central Arizona cities traditionally work together to build regional treatment plants that can deliver more water for less money.

Valley cities treat two kinds of water for drinking: most of it is surface water, which is Colorado, Salt and Verde river water delivered by canals, and some groundwater pumped by wells. Cities also treat and recycle wastewater. The treated wastewater is stored underground for future use and also used to irrigate large expanses of turf, such as at schools, parks and golf courses. One of the Phoenix Metropolitan area’s oldest joint water projects is the 91st Avenue Wastewater Treatment Plant built in 1968. It is operated by Phoenix but owned and used by AMWUA’s five original member cities: Glendale, Mesa, Phoenix, Scottsdale and Tempe. Most of the treated wastewater this plant produces is shipped through a pipe to cool the Palo Verde Nuclear Generating Station 36 miles west of the plant.

 

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Pyramid Peak Water Treatment Plant is jointly owned by the cities of Peoria and Glendale.  Photo: Black & Veatch

 

For the next 50 years, joint water and wastewater plants were built all over the Valley to expand capacity, reduce costs and add redundancy. Water professionals are never satisfied with “enough” water. Cities build redundancy into their water supplies and systems to ensure water flows to their residents and businesses despite shortages, infrastructure failures or large fires. For example, the City of Peoria’s goal is to have a six-year supply of water stored underground and the city is about two thirds of the way to meeting that goal.

Right now, the cities of Peoria and Glendale are working on an upgrade and expansion of a water treatment plant they jointly own just north of Happy Valley Road near N. 63rd Avenue. Pyramid Peak Water Treatment Plant was originally built by Glendale in 1986 to provide drinking water to homes and businesses on the city’s growing north end.

 

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Inside the Pyramid Peak Water Treatment Plant   Photo: City of Glendale

 

In 1996, the City of Peoria needed to bring its allocation of Colorado River water through the Central Arizona Project (CAP) canal to the homes and businesses growing on its north end. Peoria already had the Greenway Water Treatment Plant where it treated its supply of Salt and Verde river water (delivered by Salt River Project) and had numerous wells located throughout the city.

Peoria faced the expense of building, staffing and operating its own plant, including the extended process needed to create a separate turnout into the CAP canal. Seeking a better solution, Peoria approached neighboring Glendale with a plan. Peoria would pay Glendale to expand the existing Pyramid Peak Water Treatment plant to increase production from 30 million gallons per day (mgd) to 39 mgd.  Peoria paid for and received the capacity to produce drinking water at the rate of 9 mgd and meet Peoria’s current and future needs. Glendale would continue to operate the plant but the two cities would be co-owners and share operating costs proportionally. The agreement was signed May 15, 1996 and the expansion completed by July 21, 1998.

Last year the cities signed an agreement to once again expand Pyramid Peak Water Treatment Plant. The new expansion will produce an additional 15 million gallons per day (mgd) to serve Peoria’s growing northwest neighborhoods. This expansion will increase the plant production from 39 mgd to 54 mgd.  The entire project includes the expansion and upgrades to the existing facility and will cost about $72 million. Glendale and Peoria will proportionally share the $22 million cost to replace and upgrade the older equipment in the plant, such as pumps and tanks. Peoria will pay $50 million for the expansion and fund this part of the project through the Water Infrastructure Finance Authority (WIFA). WIFA is a small federal agency that provides revolving loans to utilities to improve, build or expand water infrastructure.

Glendale held its first open house in April to gain input from the plant’s neighbors. The cities expect construction to start in the summer of 2019 and the plant to be operating by the summer of 2021. This partnership is just one more example of how water professionals consistently collaborate to solve large and small water challenges.

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.

So, Exactly How Much Water Are We Talking About?

By Warren Tenney

When it comes to meeting the water needs of a thriving desert economy, the amounts can really add up. Communicating these amounts in a way we can relate to sometimes misses the mark. We’ve all read or heard something like “That’s enough water to fill 200 Olympic size swimming pools.” It’s not an easy example to imagine, other than to think, “I guess that’s a lot of water.”

Trying to understand water news or even your water bill can be a challenge given the different measurements used. Just like we have feet, kilometers and miles for distance and Fahrenheit, Celsius and kelvin for temperature, water is measured with different units depending on the context. No one would talk about the distance between Phoenix and Tucson in feet and water professionals do not generally talk about the amount of water stored behind Hoover Dam in gallons.

Here’s a quick guide to some of the ways you see water measured in media reports, research, and your water bill.

Gallon: This is the easiest one but the most important. Everyone knows what a gallon of milk looks like. Nearly all water bills display usage in gallons. The average single-family home in Phoenix uses an average of just over 10,000 gallons per month (more in the summer, of course, and less in the winter). These 10,000 gallons of water per month are a real bargain. They’re delivered to your home ready to drink for one-third of a penny per gallon. If average cost-conscious water consumers tried to replace the water service to their homes with generic refillable five-gallon jugs at their local grocery store, their water bills would be around $2,500 per month. Not to mention the transportation costs of moving over 2,000 of those jugs.

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91st Avenue Waste Water Treatment Plant  Photo: City of Phoenix

MGD (million gallons per day): This measurement is used most often in the context of water delivery and sewer systems. For example, the City of Goodyear recently announced it would construct an eight “mgd” water treatment plant to treat a portion of its supply of Colorado River water. An average flow of just one mgd is enough water to supply nearly 3,000 average single-family homes in Phoenix annually. On the larger end of the scale, the state’s largest wastewater treatment plant at 91st Avenue in southwest Phoenix treats an average of 140 mgd but has the capacity to treat 230 mgd. Much of the treated wastewater from this facility is used to cool the Palo Verde Nuclear Generating Station.

AF (acre-foot): This measurement takes a little imagination. It is the volume of water it would take to cover one acre of land in one foot of water  – or 325,851 gallons. If it helps, it takes two “AF” to fill an Olympic-sized swimming pool and is how much water three average Phoenix metro households use in a year. Acre-feet are usually used to measure huge volumes of raw, untreated water, such as how much water is in a reservoir. Here’s an incomprehensible number: each year 1.5 million acre-feet of Colorado River water flows through the Central Arizona Project canal delivering a renewable supply of water to Arizona’s cities, industries and farmers. 

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CAP Canal near Picacho Peak  Photo: Central Arizona Project

ccf (centum cubic feet): For us non-Latin speakers, “ccf” is 100 cubic feet. One hundred cubic feet would fill a 5-by-5 feet box that is 4-feet tall  – or 748 gallons. While most AMWUA cities calculate water bills in gallons, if you receive a water bill from the City of Phoenix and examine it closely, you’ll see it is based in ‘units’ of water with each unit being one ccf. The average Phoenix single-family home uses 13.6 ccfs per month. Why use ccfs and not gallons? The city’s old water meters were designed to track your usage in ccfs and it is too costly to change the billing system.

cfs (cubic feet per second): “Cfs” is used to measure rates of flow, such as in rivers, canals, or large pipes. For example, the Mississippi River discharges an average of 600,000 cfs into the Gulf of Mexico. The Central Arizona Project canal, by comparison, delivers an average of 2,100 cfs to the state’s cities, industries and farmers. Cfs numbers vary widely depending on their context but even very low numbers can really add up. Consider this, a flow of just one cfs means 7.5 gallons every second. A flow rate of only one cfs over the course of a single day equals the amount of water used by about five average Phoenix single-family homes during an entire year.

Understanding and relating to water information is crucial to participating in the ongoing discussions about how Arizona can ensure we all have clean, reliable, affordable water supplies. Numbers make up a big part of that discussion.

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.

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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.

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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. 

 

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.

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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.

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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.

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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.

Defying Mother Nature: Creative Solutions To Avoid Shortages

By Warren Tenney

The U.S. Bureau of Reclamation recently confirmed Arizona would not face a declared shortage of Colorado River water in 2017. This is good news but Arizona’s cities, farmers and industry leaders must continue to plan for an eventual shortage on the Colorado River, which could come as soon as 2018.

The U.S. Secretary of the Interior has the authority to declare shortages on the Colorado River. Under current agreements, this occurs when the Bureau of Reclamation projects that water levels of the Colorado River’s primary reservoir, Lake Mead, will be below an elevation of 1,075 feet in January of the following year. Lake Mead is currently right at 1,075 feet as the result of a sixteen year drought. Water levels are further exacerbated by the long-standing imbalance created from more water being taken from Lake Mead than what flows into it.

The primary reason we averted a shortage declaration in 2017 is because we did not rely solely on Mother Nature. This may sound audacious, but we avoided shortage in large part because Arizona and Central Arizona Project (CAP) led a successful effort to get CAP customers, the federal government, our neighboring Colorado River basin states, and Mexico to consider ways to slow Lake Mead’s declining water levels. The goal has been to keep water levels in Lake Mead from declining and jeopardizing the health of the Colorado River system. This is especially critical for Arizona because Central Arizona Project (CAP), the state’s main delivery system for Colorado River water, has what is called “junior priority” and must take the first cuts when a shortage is declared. This is why Valley cities are closely following what happens on the Colorado River and in Lake Mead.

CAP canal brings water to central Arizona. Photo: CAP

Here’s how Arizona has pushed back a shortage for now.  Over the last couple of years, CAP asked its agricultural and municipal customers to voluntarily leave water in Lake Mead. The target was to store 345,000 acre-feet of water in Lake Mead. This goal will be achieved by the end of this year. As part of this effort, the Cities of Phoenix, Scottsdale, Glendale and Peoria agreed not to take their full allocations of Colorado River water.  Also, 11 agricultural irrigation districts in central Arizona agreed to reduce their use of Colorado River water.  These voluntary efforts have collectively conserved water in Lake Mead and helped prevent a shortage.

Efforts to conserve and intentionally create additional water in Lake Mead should continue and be expanded to slow Lake Mead’s falling water levels.  Municipalities are willing to continue to find ways to leave more water in Lake Mead. There are rules about how much water a state can intentionally save in Lake Mead. Despite this obstacle, Arizona should continue to work with its Colorado River partners to find more ways to protect Lake Mead and strengthen the overall health of the Colorado River. This includes finding creative arrangements going forward that provide incentives for cities to leave even more water in Lake Mead.

A look inside CAP’s control room. Photo: Philip A. Fortnam

Addressing water challenges is complicated with the devil always in the details. This will certainly be the case as we seek to strengthen our preparation for a shortage declaration.  Key to that preparation will be creativity and collaboration, which were central to our efforts to hold back a shortage for another year. 

Arizona leads the nation in creatively managing its water resources.  Among all the western states, Arizona is in the best position to weather the challenges faced by municipal water utilities. That’s because Arizona’s water professionals and leaders in industry, agriculture and municipalities have a long history of working together to solve water problems. Arizona’s responsibility is to continue to collaboratively and creatively tackle our current challenge of how best to protect Lake Mead and the health of the Colorado River so we can continue to use this important water source.

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  

Peak Demand Dictates How Cities Build Water Infrastructure

By Warren Tenney

It’s no surprise that demand for water in the Phoenix Metro area reaches its peak during the summer months. What may be surprising is that demand nearly doubles from the winter months to the summer months. In February 2015, City of Peoria customers – businesses, apartment buildings and homes – used 2,940 acre-feet of water. In July, Peoria’s peak rose to 6,516 acre-feet of water. (One acre-foot of water is enough to cover an acre to the depth of one foot or enough to serve an average of three Arizona households for a year.) In December 2015, City of Mesa water customers used 5,899 acre-feet of water. In July 2015, Mesa water customers used 10,503 acre-feet.

The annual pattern of peak demand can look slightly different from year to year, depending on fluctuations in heat and when monsoon storms arrive. The chart below shows Mesa’s annual water production for the past 5 years. Peaking in Mesa happens most often in July, but a hot June and a good July monsoon can mean that the peak month could be June.Screen Shot 2016-08-17 at 8.10.27 AM

Watching water-use trends and peak demand is critical to planning and building water infrastructure. Here’s why:

  •  Annual Peak Demand: Cities build infrastructure to meet annual peak demand. It would be cheaper to order just enough water and build just enough pipes, pumps and small reservoirs within a water system to meet average water use but that would make water delivery to your faucets unreliable during peak demand times. More is invested in water treatment and distribution systems to ensure they are built to provide water for the hottest days when landscape irrigation systems, pools and cooling towers are working at maximum capacity.
  • Daily Peak Demand: Each day, demand for water peaks in the morning and, again, in the evening hours. That means water managers are diligently filling a water system’s reservoirs overnight to make sure enough water is ready to be pumped to homes when hundreds of thousands of residents step into their showers between 6 a.m. and 7 a.m. Then water managers dial back around 9 a.m. when demand lessens and to prepare for the after work demand.

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    Small reservoirs keep water available for peak demand. Photo: City of Mesa

  • Safety Peak Demand: Being ready for daily and seasonal water demands isn’t enough. Water managers must maintain water supplies and build water systems for the what-ifs. What if it’s 6 a.m. on a July morning and firefighters call for more water to fight two house fires and a brush fire? What if the system is just dialing back to accommodate a low demand time when a water main breaks spewing hundreds of thousands of gallons of water meant for customers into the street instead? A water distribution system must have supplies, pipes, reservoirs and pumps in reserve to keep water running to customer faucets while employees fix the break or provide water for fire suppression.

Most cities, including Mesa and Peoria, use a computer program called Supervisory Control and Data Acquisition or SCADA to track water demand throughout their systems. The program allows city employees to keep their eyes on each part of the water distribution system remotely and in real time. Operators use this innovative computer program to review water distribution continually throughout their service area and to track peaks in demands. For example, a sudden change in pressure could mean firefighters need high volume and increased pressure to put out a fire, a construction site is filling a large water tank, a reservoir is overflowing or there is a break in the system and the city is losing water.  Utility workers can quickly respond to investigate and correct the problem to significantly reduce any disruption to your water service. 

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Photo: City of Mesa

During the last two decades, while Mesa and Peoria have grown by hundreds of thousands of people, the water used by city customers, even during peak demand months, has remained nearly flat. Cities helped to fuel this accomplishment by promoting a conservation culture, which includes encouraging drought-tolerant landscapes and the use of water-efficient appliances and fixtures, and helping residents find and fix leaks. Want to help lower your city’s peak demand? Start outside where as much as 70 percent of a home’s water is used. AMWUA’s Smart Home Water Guide can help you find and fix leaks. AMWUA’s landscape pages can help you select drought-tolerant plants and trees, design a lovely yard, and efficiently water your landscape for maximum beauty.

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.