This article documents the outcome in 1950 of one of the reclamation project dams on the Umatilla River.
Brown Silt Kills Dam; Old Problem
By Robert E. Swanson
Silt is the No. 1 problem behind many a dam. When billions of soil particles are washed down from cultivated fields and are deposited-layer upon layer, year after year - in a reservoir, they fill the space intended for water. Then the reservoir becomes a Davey Jones grave, in reverse.
Take the case of Furnish dam, located 13 miles downstream from Pendleton, on a sweeping curve of the Umatilla River. One of our least known dams, the Furnish was built in 1909 at a cost of about $125,000. Its purpose was to impound 5500 acre-feet of water for irrigation. Many people thought it to be the finest of its kind in eastern Oregon.
Today, silt beds extend back fro the structure for 21/2 miles. The silt resembles chocolate in a giant spoon, through which the river cuts deeply now into its original channel. Deposits at the lower end measure as much as 20 feet deep and are used for growing creeping alfalfa experimentally, under sprinklers. The dam itself stands useless and almost forgotten.
Furnish Pendleton Banker
The story of the dam dates back 45 years to the very beginning of what is now the Stanfield Irrigation District. It was in 1905 that W.J. Furnish began construction of an irrigation system known as the Furnish canal, to irrigate some 10,000 acres in the vicinity of Stanfield. Furnish was a Pendleton banker. With the help of "Doc" Coe, then a Portland physician, he financed his venture. His promotional schemes quickly brought settlers from as far east as the Dakotas.
Work started four years later on the ill-fated dam.
Its purpose was to store early flood water, since the new project did not have summer water rights on the Umatilla. E.P. Marshall, a brother-in-law of Furnish, took charge of operations. Marshall imported laborers--mostly Greeks--who mixed and poured concrete by hand for the 800-foot long core which went down 12 feet to bedrock.
A second crew, handicapped by the lack of modern air-power tools, blasted two outlet tunnels under the dam, using a few hand drills, picks and shovels, and plenty of brawn. These outlets, six feet high and four feet wide, were drilled out of solid rock. Holes made for blasting were drilled by three-man teams, two men on the hammers and on on the drill.
Still a third crew sliced through a flood spillway, or overflow channel on the south band of the river. From this point they conveyed earth to the dam by means of two-wheeled dump carts on narrow gage track. They deposited the earth in thin layers against both sides of the core, until the dam it its base was 400 feet thick.
And so the job went.
Meanwhile, Union Pacific railroad officials entered the picture with the announcement that they planned to relocate much of their track between Pendleton and Yoakum, three miles below the Furnish dam. Included in their improvement program was a 900-foot tunnel to replace Horseshoe Curve, a stretch of track paralleling the reservoir. The "horseshoe" is said to have formed a perfect representation of the genuine article. The tunnel, completed in 1909, was destined to play an important role in this unfortunate drama of "the dam that died too soon."
Furnish and Marshall apparently figured their new reservoir would "last forever." One Stanfield farmer recalls hearing Marshall say in answer to a question on the subject of siltation: "you and I will never live to see the day when that reservoir fills up."
Silt Trouble Started Early
But time and the river proved differently, Erosion silt--the soil washed from farm and ranch lands--started giving them trouble the very first year. It came from the wheatlands to the north and east of Pendleton, down Wild Horse creek; and down the Tutuilla creek, draining the south portion of the Umatilla Indian Reservation--into the river and into the Furnish Reservoir.
By 1916 the Umatilla was depositing silt on the floor of the reservoir at the rate of 180 acre-feet a year. Nobody bothered to measure the additional amount pouring annually through the outlet tunnels and over the spillway.
By 1924 the storage capacity behind the dam had been reduced from 5500 to 2800 acre-feet. And by 1925, when Stanfield farmers saw little advantage in using the reservoir for storage, something like 6,000,000 tons of silt lay heavy and cold at the bottom of the lake.
Bedeviled by water troubles, the Furnish Ditch Co. obviously needed special attention.
Federal Aid Comes
Soon that aid was forthcoming. In 1924 the federal reclamation service (now bureau of reclamation) purchased a block of land on McKay creek, south of Pendleton, and started work on the new storage dam. Two years later McKay reservoir was ready for operation. The Furnish Ditch Co., after changing its name to the Stanfield Irrigation district, to satisfy legal requirements, made its first purchase of McKay water. A similar arrangement continues in contract today.
But what about the Furnish dam?
The story of the dam reaches a climax which dates to 1934. By that time the Umatilla river had poured so much silt into the reservoir that water choked the entire valley above the dam during flood periods. Not infrequently the Union Pacific tunnel became flooded with water. When this occurred, the railroad was faced with the job of pumping the water out. Though this procedure involved considerable expense, it was more economical than waiting for the water to recede and then repairing the damage left in its wake. Either way, it was a costly situation.
U.P. Busts Dam
So the railroad bought the dam. They bought the reservoir site, too. And in the summer of 1934 they sent to the dam a crew of men with bulldozers and carryalls. After removing the center section of earth, these men dynamited the concrete core, allowing the river to pass through. And thus the once-proud Furnish dam was destroyed.
So much for history. Now let's look at the silt beds as they exist today. E.F. Burlingham and Sons, seedsmen of Forest Grove, are leasing them from the railroad for raising creeping alfalfa seed. Burlingham is among the few seed companies in the United States now producing this seed. According to William F. Cyrus, manager of the farm, "When we first approached the Union Pacific, they refused to consider leasing the area for fear we might do something that would cause the water to back up again and flood out their tunnel." The railroad would agree, however, if sprinkler irrigation was used, and the deal went through on that basis.
Burlingham's original goal was to raise certified seed, but weeds created a terrific problem. Says Cyrus, "We've got seed of every weed that ever grew in the wheat country buried in this silt."
No one can put a dollars-and cents price tag on the damage--to crops, to farms, to humans--caused by siltation of the Furnish dam. A search of Stanfield Irrigation district records does no reveal this information. The few farmers who remember those early days have made such comments as, "The water shortage was awful, and We just marked time, waiting for McKay to be built."
Could the life of this dam have been extended? The answer is yes.
Soil Conservation Vital
While certain hydrological factors apparently were not considered when the Furnish dam was designed, conservationists believe that better land use on the wheatlands above Pendleton would have added years to the life of the reservoir. Strip cropping, contour cultivation, stubble mulching, grass-legume rotations--these practices, by keeping the soil in place, would have helped to do the job. The fact that conservation will do the job has been proven on several watersheds throughout the West.
Siltation, in other words, can only be fought at its source. If the fight is not waged, silt continues: the No. 1 problem behind any dam.