Before the city was founded, the river would flood every spring, sometimes dramatically, with the melting of the winter snowpack.
In the spring flood of 1862, some analysts believe the Boise River sent down a flow of 100,000 cubic feet per second. That's enough water to inundate the valley from the foothills to the bench.
In those days the river was always carving new channels, ripping up trees, even altering its course on its way to the ocean. The early pioneers avoided settling in this turbulent floodplain, and that's why Boise's downtown was not built on the river.
"Throughout all these decades of the 19th Century and even into the 20th Century you don't hear about houses being flooded or businesses being flooded or threatened. Instead, you hear about, well someone saw a shed floating down the river during a flood," said Susan Stacy, a local author and historian.
Stacy wrote "When the River Rises," an in depth look at the history of the Boise River.
The pioneers didn't appreciate the river's aesthetic value, there were no greenbelts back then, instead it was used as the city's sewer with numerous quarries and slaughterhouses on its banks. But right from the start, they realized by diverting its flow they could turn sagebrush desert into productive farmland.
"It turned out to be extremely successful and the same basic idea, diverting water from the river, continued for the next century and on into today," Stacy says.
As the areas under irrigation grew, more water was needed than the river could bring, especially in late summer once all the mountain snow was gone. So, over the decades, people built four large reservoirs, Lake Lowell, Arrowrock, Anderson Ranch, and Lucky Peak, to store the spring floodwater so it could be used all summer.
This also solved the yearly flooding problem.
There has only been one year since Lucky Peak was completed in 1955 that the river sent down more water than the reservoirs could handle. The historic flood of 1983 caused major damage along the river, but the flooding would have likely been a lot worse if not for the dams.
Nowadays, water managers have sophisticated technology which they can use to study the river without even having to go out into the water. At the Idaho Water Building, the University of Idaho operates a giant flume of water.
"We've done a lot of sediment transport experiments that relate to the sustainability of the mountain streams, to mountain streams that have been disturbed by past mining and are being restored," says Dr. Ralph Budwig, an ecohydraulics scientist.
The more scientists learn about the streams that feed the Boise River, the more we know about how to keep Boise's favorite river healthy.
So when you enjoy the river this summer, treat it with respect, because it truly is the treasure of the Treasure Valley.