Water made arid Arizona grow, but geography and gravity determined where that growth would occur.
Those forces favored the flat river valleys downstream from massive, mountainous watersheds where creeks and streams gathered into mighty rivers.
The critical moment in putting water to work in Arizona came 100 years ago this past Friday when ex-President Theodore Roosevelt christened the dam named in his honor in a rocky notch of the Salt River, 76 miles east of Phoenix, just downstream of the Salt's confluence with Tonto Creek.
Roosevelt Dam provided the first dependable water supply to the farms of the Salt River Valley, the territorial capital of Phoenix and the burgeoning agricultural communities of Tempe and Mesa.
The impact was immediate.
A decade-long drought that ended with calamitous floods in 1905 had fallowed farm fields and sent some people packing from the Salt River Valley.
In 1910, Tucson had a bigger population than Phoenix. Cochise County, with its copper-mining powerhouse at Bisbee, contained more people than Maricopa County.
The dam, which increased agricultural production and brought electrical power to the Salt River Valley, reversed that.
In the next decade, irrigated acreage would more than double, Phoenix would nearly triple in population and Maricopa County would grow from 34,488 residents in 1910 to 89,576 in 1920.
There were other forces at work. Phoenix had recently added to its railroad connections, and World War I created a demand for an increasingly important cotton crop for uniforms and tires. But everything hinged on a dependable water supply.
With that in place, Phoenix and its growing number of sister cities in the valley became the center of economic and population growth in Arizona. Today, Maricopa County contains nearly 60 percent of Arizona's population.
The Salt River Project, which has operated Roosevelt since its inception, now serves water and power to about a million customers from six reservoirs on the Salt and Verde rivers. Roosevelt Dam, with a massive expansion completed in 1996, accounts for two-thirds of SRP's storage capacity of more than 2.3 million acre-feet.
THE VALLEY CITIES
The settlements that the Salt River Project watered into cities had begun modestly just a few years after the Arizona Territory was split off from New Mexico by President Abraham Lincoln in 1863.
The first farmers harvested wild grasses along the Salt River to supply Camp McDowell (first named Camp Verde) on the Verde River.
In 1867, John William "Jack" Swilling hired teams of horses and men to dig out irrigation ditches that flanked the Salt River, using the imprint of those built centuries before by the Hohokam who had disappeared from the area by 1400.
A town site for the agricultural community that rose from those long-abandoned canals was named Phoenix in 1870. In the census that year, the Salt River Valley contained 240 of the Arizona Territory's 9,658 "official" inhabitants. The Indians were not counted.
In 1871, Tucsonan Charles Trumbull Hayden established a ferry across the Salt River and four years later a flour mill at a site he named Tempe.
The agricultural community of Mesa was settled by Mormons from Utah and Idaho in 1878.
But Phoenix was the city on the make, said Jared Smith, curator of history for the Tempe History Museum.
"Phoenix seemed to have a lot of boosters in its favor. Getting the state capital (in 1889) was a key component," he said. "It was always a bigger town."
The boosters also organized drives to connect Phoenix to the transcontinental railroads that had bypassed it to the north and south. Tucson had rail service in 1880. Tiny Flagstaff sprang into being when the railroad came through in 1882. By 1895, Phoenix had connected itself to both lines.
"In the grand scheme of things, they were a poor little farm town," said Smith, who spent 10 years as Mesa's historian.
Tempe also remained a small town until the boom that followed World War II, Smith said. Tempe Normal School, founded in 1885, evolved into Arizona State University in 1958.
"Phoenix became the retail hub," Smith said. "Everybody from Tempe and Mesa went to shop in downtown Phoenix."
TAMING THE SALT
Phoenix would not grow, however, until it tamed the Salt River, whose flow fluctuated wildly.
Groups of farmers built diversion dams and big canals, but they didn't work when the flow slowed, and they were wiped out when the floods came.
The need for a dam was emphasized by a decade-long drought that began in 1894 and ended with a vengeance in 1905, with spring floods that destroyed diversion dams, canals and the railroad bridge across the Salt River.
By that time, construction was already under way on what was then called Tonto Dam. The farmers had organized and the city's boosters had lobbied the federal bureaucracy and the Congress to include privately held land in the National Reclamation Act, which provided money from Western land sales for dam projects.
The Salt River Valley Water Users' Association was formed. "Farmers put up their lands up for collateral - a $60-an-acre charge they would have to repay. They were taking a great leap of faith," said Shelly Dudley, a Salt River Project historian.
The dam's cornerstone was laid in 1906 and construction completed in 1911 - a year before Arizona became a state.
That might not have happened without the dam, said Tempe historian Smith.
"Building the dam was massive," he said. "It is not a complete coincidence that statehood happened a year afterward because now Arizona is showing signs of stability. This now says something different is happening and the federal government is willing to put this major investment into Arizona."
The residents of the Salt River Valley were fortunate to have settled downstream of a watershed that was owned mostly by the federal government.
Tonto National Forest was created in 1905 to protect the watersheds of the Salt and Verde rivers. In essence, the federal government allowed folks in the Phoenix area to lay claim to every drop of water that fell over 13,000 square miles.
Communities within the watershed lost any right to build their own dams, and some claims are still being negotiated and adjudicated 100 years later.
The city of Payson, surrounded by forest streams that run toward Phoenix, received its first allotment of surface water from the Salt River Project as part of a larger settlement of water rights just last year.
Doug Kupel, a historian who researches water and environmental issues for the city of Phoenix, said the setup makes sense in many ways. "Where would you rather have the people - in one place where you have the infrastructure to serve them or scattered across the uplands of Northern Arizona, having individual wells? It's just not an efficient way, or a way to preserve the environment," Kupel said. "It is the blessing or curse of geography."
Tucson's boosters, he noted, once planned to dam Sabino Canyon before deciding it was a long way to go for water from a single creek.
But while Tucson lacked a good dam site, Phoenix sat beneath the pinch point for a major watershed, Kupel said: "That was the perfect place to build a dam, just below the confluence of Tonto Creek and Salt River. It makes a beautiful, bird-wing-shaped reservoir."
It filled quickly, spilling for the first time in 1915.
With additions completed in 1996, the reservoir behind Roosevelt Dam can now hold nearly 1.7 million acre-feet of water, about two-thirds of the Salt River Project's surface water storage.
It's not enough. The Phoenix Water Management Area now uses water from the Central Arizona Project Canal, in addition to the Salt and the Verde, pumped groundwater and effluent. Agriculture is shrinking. Population is growing.
When former President Roosevelt threw the switch that let water through the dam on March 18, 1911, he predicted the area it watered would one day have a population of 100,000.
Maricopa County is 38 times that number today. Water the desert, and it grows cities.
Coming April 10
The second of our five special sections leading up to Arizona's centennial on Feb. 14. The April section celebrates the lure and lore of the Old West.
Tough sheriffs, cattle rustlers, stagecoach and train robbers, vigilantes, gamblers, vaqueros and dancing girls. The stuff of Hollywood movies actually did take place - right here in Southern Arizona.
In addition to discussions with the historians noted here, facts for this story were drawn from two books:
• "Building a Legacy: The Story of SRP," published by the Salt River Project
• "Phoenix: The History of a Southwestern Metropolis," by Bradford Luckingham, published by the University of Arizona Press.
How the population grew and shifted
Population: Tucson Phoenix Maricopa County Arizona
1900: 7,531 5,544 20,457 122,931
1910: 13,193 11,134 34,488 204,354
1920: 20,292 29,053 89,576 334,162
1930: 32,506 48,118 150,970 435,573
2010: 520,116 1,445,632 3,817,117 6,392,017
Contact reporter Tom Beal at firstname.lastname@example.org or 573-4158