10 CAP Facts: The Canal that Made Modern Arizona

America has 3200 counties. Which one do you think welcomed the most newcomers in 2017?

Yup.  Maricopa County.

The US Census Bureau says we added 73,000 people last year and topped 4.3 million for the first time.

When you’re splashing around with the kids in the pool or launching your tee shot into the drink, you may wonder how a place that gets (maybe) seven inches of rain a year can survive as a thriving metropolis, or support the millions heading our way in the next 20 years.

A big part of the answer flows underneath those modest bridges you drive across all over the Valley:  the Central Arizona Project (CAP) canal, one of the most under-appreciated engineering feats of all time. Its sheer audacity still staggers the imagination and makes today’s public projects seem as inspiring as bus shelters.

The CAP is a fully-constructed artificial river – longer than the Allegheny and much longer than the Hudson –  that traverses 336 miles of the driest, hottest, most hostile terrain in the western hemisphere. For perspective, the much-more-famous Panama Canal is only 46 miles long and the legendary Suez, just 48 miles. Have you made the drive from Phoenix to San Diego? That’s how long the CAP is.

Real rivers roll merrily along, letting gravity do all the work. Not the CAP. To get to Phoenix and Tucson, the aqueduct muscles its way 2,400 feet uphill, tunneling through mountains and even flowing underground as it delivers 1.5 million acre-feet of Colorado River water every year from Lake Havasu to the Valley and on to Tucson. Its 13 massive, round-the-clock pumping stations are immensely powerful, and make the CAP Arizona’s top consumer of electricity.

The Colorado River delivers about half the water the Valley uses each year via the CAP, though the distribution, storage, swapping, lending, crediting and debiting that goes on would make William Mulholland’s head hurt. The financial analogies are all too real – Arizona operates a state Water Bank to keep track of it all. CAP water goes to contracted users in Maricopa, Pinal and Pima counties, which include a dozen Native American communities, municipalities, industry and development interests. The biggest user though is agriculture.

The Vision Thing

It’s been 96 years since the Colorado River Compact evenly divided 15 million acre-feet of river water among four upper Basin States and three Lower Basin States (Arizona, Nevada and our water frenemy, California).

The Lower Basin states use Lake Mead behind Hoover Dam as an on-river reservoir.  The Upper Basin’s reservoir is upstream at Lake Powell, behind Glen Canyon Dam. Per the Compact, the water levels of the two reservoirs must remain the same, relative to each other, which causes Lake Powell to sometimes send water downstream to Lake Mead. Believe me, it gets a lot more complicated than that.

In 1944, as war raged around the world and fewer than 100,000 non-air conditioned souls lived in Phoenix, the state of Arizona finally ratified the Colorado River Compact. We had stalled for more than 22 years.

Arizona had problems with the allotment of water to the Lower Basin and was unhappier still with specific allotments within the Lower Basin.

How unhappy?  In one instance, in 1934, a mightily ticked Arizona governor called out the National Guard when the Feds and California starting building Parker Dam, siphoning Colorado River water to Cali without consulting Arizona. Governor Benjamin Moeur even launched a two-boat “Arizona Navy” to stop dam construction on the Arizona side. The enterprise seems laughable now, but it was no joke.  There were 20 machine guns trained on the dam site from Arizona, and 40 riflemen took up positions. Even the “navy” personnel had military-grade field rifles.

With disputes such as these settled more or less amicably by 1944 (things move at the speed of canyon formation in water negotiations) Arizona ratified the Compact, in hopes that would clear the way for CAP construction. That’s how long the CAP idea has been shimmering on the desert horizon.

What did we get for all that stalling, jockeying and navy-launching? The right to 2.8 million acre-feet of Colorado River water per year. That’s a huge amount – roughly enough water for 11.2 million people, if every drop was used for residential purposes, which it is not.  74 years later, just about half that many people live in the CAP service areas. No matter how you look at it, that’s good long-term planning. 

It took imagination and guts to advocate for the CAP so long ago. Only about a half million people lived in the entire state in the 40’s, and only a few could picture Phoenix as one of the nation’s largest cities, or foresee a day when the Tucson area would have more than a million people.

Arizona Senator Carl Hayden was one of the handful of visionaries. In Congress for an astonishing 56 years, Hayden bulldogged the CAP for more than a quarter-century, finally seeing it authorized by President Lyndon Johnson just before Hayden retired in 1968 at age 88. (Johnson’s remarks that day were recorded, and live today as a remarkable online video produced by the CAP, which Johnson seems to narrate).

The CAP cost a mind-boggling $4 billion – Manhattan Project money – or about $30 billion today.  The Feds put up almost all of it. Arizona agreed to form the Central Arizona Water Conservation District to pay the money back, manage the canal system and commit to delivering Arizona’s entire allocation of Colorado River water.  The CAWCD is still at the heart of Arizona water management and is still working on all three of these objectives. You’ve probably noticed candidates for its 15-member volunteer Board on your November ballot.

Then and Now

Though it may have seemed a little crazy in 1944, when construction finally began in 1973, the arrival of the CAP was highly anticipated in Phoenix and Tucson.  The boom was on, and Arizona – most notably Tucson, which has nothing like the Valley’s Salt River Project – was pulling far more water from the ground than was being naturally replaced.

Getting the water here was a straightforward, though brutally difficult, process. Distributing it resided –and still resides – in the byzantine realm of lawyers, politicians, government staff and civil engineers. The word that comes to mind when perusing a CAWCD Board agenda is – dry.

Part of the plan was – and is – to use Lake Pleasant as a storage reservoir for entities around the Valley that have rights to CAP water, and for that purpose, the lake’s capacity was quadrupled as part of CAP construction. (Note to alarmed lake visitors: annual changes in the water level are related to whether CAP water is being accumulated or distributed, not weather conditions.)

Thousands of workers spent 20 backbreaking years digging and blasting through, over and under hundreds of miles of mountains, stream beds and forbidding, uninhabited terrain as the CAP snaked its way to central Arizona’s population centers. In 1993, the canal reached its endpoint southwest of Tucson and was declared substantially complete, though it is still not finished. It may take another 10 to 20 years to build all the distribution facilities.

So who gets the water? Sorting through who gets it and why is something like thwacking though a brush-choked arroyo with an Exacto blade. In your underwear.  Suffice it to say that in order to access the water, municipalities, Native American communities, agriculture, industry, and development interests must have contracts with the Central Arizona Water Conservation District, which is itself contracted by the US Department of the Interior to receive and distribute CAP water. A separate entity, the Central Arizona Groundwater Replenishment District, operated by the CAWCD, can utilize CAP water to help developers and growing cities meet their legal requirement to demonstrate long-term (100-year) “assured water supplies” by agreeing to replenish the groundwater those entities withdraw that exceeds the limits set by state law. The CAWCD can levy a tax to recover its costs from municipalities. Everyone else pays a fee. This is particularly important for some West Valley cities, which are not part of the SRP system and are far from CAP aqueducts.

Got that?

Drought afflicts the Colorado River Basin these days, though water levels are not at a critical stage and there is a long way to go before reductions come into play that would affect daily life in the Valley. Still, conservation is not only prudent but part of the ethos of living in a dry place, and the CAWCD encourages everyone to practice it.

Today, areas served by the CAP receive about 1.5 million acre-feet of Colorado River water per year. Incredibly, that is 700,000 acre-feet less than the CAP’s capacity, and just 53 percent of Arizona’s total annual Colorado River allotment. Besides serving those already mentioned, Colorado River water is stored underground, generates electric power and replenishes groundwater.

Like the desert sun, CAP-delivered water is seemingly everywhere in central Arizona. And like a lot of Arizonans, it’s traveled far from home to make our state what it is today.   

About those ten facts!  Here they are:

• The 336 mile-long canal, its pumping stations, and turnouts are operated entirely remotely from a control room in north Phoenix. A rotating team of three or four operates the secure facility 24/7/365, running the entire system from a bank of computers while monitoring a display that takes up two walls of a room the size of your basic city council chamber. It’s efficient, cost-effective, and pretty damn cool.  
• The original Waddell Dam sits at the bottom of Lake Pleasant, intact. Completed in 1927, the dam was submerged when the lake was expanded to hold CAP water by the construction of the New Waddell Dam, completed in 1994.
• An acre-foot equals 325,851 gallons, the volume required to cover a square acre to a depth of one foot. If you are a ‘typical family of four,’ you use about one-third of an acre-foot per year, around 108,000 gallons.
• The CAP pumps water at a rate of roughly 3,000 cubic feet per second from Lake Havasu. That’s one acre-foot every 14 seconds. A typical family of four would be knocked into New Mexico standing in front of a stream that powerful.
• Only 4% of CAP water is lost to seepage and evaporation. Covering the canal was discussed early on. It would have quadrupled the construction cost and required untold billions in ongoing maintenance, basically forever. Those costs would have been passed to y-o-u.
• CAP water begins its journey by being pumped almost straight uphill more than 800 feet. This marvel of sheer power takes place at the massive Mark Wilmer Pumping Station (pictured below in 1981) at Lake Havasu and looks like the world’s most dramatic roller coaster climb. (Illustrating the importance of the legal water wars in Arizona, this very first facility on the CAP is named for Wilmer, a water attorney.)

• The canal is bigger and deeper than it looks.  It’s hard to appreciate when you are concentrating on your driving, but the CAP is 80 feet across, narrowing to 24 feet at the bottom. Average depth is between 16 and 17 feet. There is a section serving as internal storage that is 160 feet wide and 80 feet deep.
• Water leaving Lake Havasu takes 3-4 days to make it to the end of the line. This means the canal is pushing relentlessly along at 3-5 miles per hour.  It does not stop, and as mentioned above, it’s deep. Do NOT let the kids get near it and don’t ever enter the water yourself. It’s not meant for recreation. It’s dangerous. It’s against the law. You will be very sorry.

The end of the line is 12 miles southwest of Tucson. Water arriving there is used to replenish Tucson-area groundwater.

• A woman named Nellie T. Bush commanded the “Arizona Navy” in the 1934 California water dispute. Bush owned the boats Arizona Governor Moeur commandeered in the mobilization, so he made her an admiral on the spot. A prominent Arizonan, Bush was a lawyer admitted to practice in California and Arizona. She became Justice of the Peace in Parker; was elected to the Arizona legislature, and was a delegate to the 1932 Democratic National Convention that nominated FDR for the first time. In 1982, Nellie T. Bush was inducted into the Arizona Women’s Hall of Fame.

• The CAP uses 2.8 billion kWh of electricity per year:   That’s enough energy to, well, push 1.5 million acre-feet of water 2,400 feet uphill for 336 miles.  Water in Arizona also generates power, so part of almost everyone’s household electrical bill is water generated.   

Bonus Fact:

• The CAP canal in the Phoenix area is marked by “Hayden- Rhodes Aqueduct” signs.  CAP and ADOT put up the signs to call attention to the canal and memorialize the contributions of Senator Hayden and former Rep. John Rhodes, who was a driving force in the House when the 1968 authorization bill was signed.  

Bonus to the bonus: Rhodes went on to become known as one of three political leaders (Barry Goldwater and Pennsylvania’s Hugh Scott were the others) who delivered the news to Richard Nixon that he did not have enough support in Congress to stave off impeachment and probably faced conviction, triggering Nixon’s resignation from the Presidency in 1974.

More river water is exported from the Colorado River than from any other river basin in the world. -Ted Cooke, CAP General Manager