Flooding and a famous flume part of East Boise’s past, present

In April 1881, 50 long-suffering Boise citizens who had seen their property damaged every spring by the floodwaters of Cottonwood Creek petitioned the mayor and City Council to annul an 1872 contract with orchardist Thomas Davis to take care of the water coming from the creek. It asked that Davis give to Boise City the right-of-way through any part of his land, to construct a flume to carry creek water to the Boise River.

On Oct. 4, 1881, the Statesman reported, “A Stone Flume. Our city fathers ask for proposals to build a stone flume on Cottonwood Creek.” The Statesman strongly opposed this as being too costly and suggested that a V-shaped wooden flume would cost much less. The council ignored this opinion and awarded a contract to low bidder Earl Race to build a stone flume for $3 per running foot.

In March 1882, “Under the direction of Mayor Pinney, a long flume has been constructed from the mouth of the canyon, through the military reservation, and the water has been turned into it. This conducts the water in a direct line from the mouth of the canyon to the river. The stream is higher now than at any time during the present winter, and the flume seems to answer all purposes.”

One of the problems that would plague those responsible for maintaining the flume was first mentioned in February 1884: Mayor James Pinney and several members of the council were “vigilantly looking after the condition of Cottonwood Creek. … A system of plank dams for keeping back the sand and gravel has now been inaugurated.” This didn’t work, and the flume continued to fill with sand, raising the water level until it overflowed and flooded the land around.

In May 1892, “Cottonwood Flume has been broken in several places by the unusually large amount of water now running through it. The snow in the mountains at the head of the creek is melting rapidly and Boise may experience another flood. Street Commissioner Haas and a large force of men are at work on the flume, however, and will endeavor to arrange it so as to have all the water run to the river.” In September that year, “The city council has decided to build a stone aqueduct to take the place of the Cottonwood flume, the timbers of which are about worn out. Mayor Pinney will receive bids for the construction of the aqueduct up to Sept. 29 at 6 p.m. Plans are now on exhibition at the office of the city engineer.”

Then in October, a contract was let to D.P.B. Pride for $1.97 per running foot, for a total of $5,000. In December a second contract was let to Pride for extending the flume from Warm Springs Avenue to the river. The flume was to be built of large sandstone slabs quarried from the foothills back of the city. In September 1893, W.T. Sanders won the contract to extend the stonework at the head of the flume for $2.80 per foot. (Pride’s bid was $350.)

In January 1894, members of the council visited the flume and were gratified to find, “notwithstanding a flood of water and sand pouring through it, there is not a break in the entire length of the aqueduct, and judging from the manner it is withstanding the force of the avalanche of muddy water that is now raging down its narrow canyon, there will be no repetition of the annual flood that has caused inestimable damage to property in this city. Last summer at a comparatively small expense, the flume was, at the suggestion of Mayor Peter Sonna, ‘pointed up’ by filling the cracks between stone slabs with mortar, making it impossible for the flume to leak. The result of that precautionary step is highly gratifying and will no doubt be the means of saving the city hundreds of dollars.”

On March 16, 1894, the Statesman reported, “Cottonwood on a tear.” A portion of the flume had washed away after it filled with sand, sending water over the sides. Two days later, after another bad break, 100 men were put to work shoveling 3 feet of sand out of the flume. In that year of severe economic depression the men worked for 20 cents per hour for day work and 25 cents per hour for night work. They were glad to get it, no matter how hard the work.

With monotonous regularity, Cottonwood Creek would continue to flood parts of Boise’s east side every spring for the next century.

This story was originally published September 30, 2017 at 10:50 PM with the headline "Flooding and a famous flume part of East Boise’s past, present."