The contract for construction of these dam features within the first step cofferdam was awarded in December 1959. A big celebration was held on 4 June 1960 for the symbolic first concrete pour, attended by the Division Engineer, Inland Empire Waterways executives, people from the surrounding communities and, of course, those directly related to the event. Construction within this cofferdam progressed without any great impediment from nature, such as floods or extra severe weather.

The cofferdam received the supreme test during the spring flood of 1961. It was designed to withstand a flood of 700,000 cfs without overtopping. To prove the computer, slide rule, and engineers were accurate, the flood that spring peaked at 693,000 cfs and came within inches of the top of the cofferdam. Man, in his quest for his considered well being, created some problems in that periodic strikes by several unions at various times delayed the progress to the extent that the contractor was permitted an extension of construction time of l74 days during the life of this contract.

In the subsequent discussion of the Ice Harbor downstream navigation lock gate, with the transition to a vertical lift type, problems of adequate construction techniques are discussed. These really came to a head at John Day where the problem of adequate welds for the type of high strength steel used came to the surface. The shop welds for the fabricated sections of this unprecedented sized gate were questioned and examined. This gate for the highest single lift lock in the world, a distinction wrestled from the Ice Harbor project by the fact that it has a design head of 113 feet compared to Ice Harbor’s 163 feet, is 88 feet wide and 113 feet high. It is an all welded structure of a series of arched girders 15 feet thick with a skin plate 1-1/8 inches thick and weighing 1,800,000 pounds.

Because of reports from Mountain Home Missile Base concerning underbead cracks adjacent to the welds in T-l steel , this District decided to spotcheck the welding on the downstream gate sections as they were shipped to the site, using radioactive isotopes and ultrasonic tests. This proved to be no short afternoon’s procedure. The request for testing was initiated in September 1961; the first two sections of gates were received at the site in February 1962; first reports on examination received in April 1962; a consultant team was employed in May 1962; extensive tests and evaluations continued until August 1962; and a decision to repair the gates was made on 10 August 1962. Erection of the repaired sections in the gate slot started on 22 October 1962 and was completed by 27 February 1963–a year and a half of careful professional evaluations and, to some extent, innovative and pioneering engineering in the handling of’ exotic steels and their use. The contract execution was delayed 163 calendar days due to the experience.

During the construction period for the north half of the river, preparations were underway on the south shore to tailor it for initiation of the second phase of construction. It was necessary to put the Union Pacific Railroad and highway onto a shoofly and detour riverward in order to prepare the narrow ledge on that side of the river for the permanent alignment for both traffic routes. This was initiated in June 1960. The railroad operates approximately 20 trains a day on its single-track line and Highway 30, a transcontinental system, carries heavy truck and auto traffic. Accordingly, heavy duty, adequate detours were a must. In addition, the state was in the process of converting the route into a four-lane section of Interstate 80N, necessitating extensive modification of design criteria for the permanent realignment. This change applied to all of the highway relocation work on the south shore.

The necessary low-level temporary traffic facilities were completed in the fall of 1961, making way for some of the permanent dam nonoverfiow structure against the cliff landward of the detours. This was started in June 1961 and completed in May 1962. That short section of dam structure, in turn, made it practical to start the grading for the permanent railroad and highway alignment over it and in the reach past the dam eastward to the mouth of the John Day River. That highway and railroad work was combined with the construction of the second-step cofferdam on the south shore, all in one package, which was started in August 1962, extending to June 1964.

In the interim period, work progressed on the north shore so that by June 1962 the permanent structures within the cofferdam were sufficiently advanced to permit the cofferdam removal. As soon as the flood season was over the south shore cofferdam was started. In order to permit work td start without delay on the powerhouse excavation, an Intermediate river leg dike was built parallel to the Oregon shore while the larger cofferdam was being completed. The final cofferdam enclosed an area of about 80 acres and was in place by November l963, encompassing the area for the powerhouse, fishladder, concrete nonoverflow sections, and the south end of the spillway.

The cofferdam design was innovative by the District staff, in that the upstream and downstream legs were designed for earth embankment materials using steel cells only for the river face, where space is at a premium and stream velocities are high. This new concept has proven highly successful, even where the differential head has been as much as 60 feet, as at John Day. The ultimate in this concept of cofferdam construction was reached at the Little Goose project where the structure to enclose a 60-acre area has only 16 steel cells around the river end of the cofferdam.

Some of the steel cofferdam cells used at John Day are among the largest ever built. They were of the cloverleaf type over 80 feet high and 72 x 55 feet in plan. They differ from other large cells in that they rest on bedrock with no overburden to lend lateral support. During this second stage of construction the river passed through 17 of the spillway bays that had been left 75 feet lower than their ultimate height. Navigation proceeded through a temporary blockout in the upper Sill of the lock and a temporary upstream entrance channel through a rock bluff. This condition for river and navigation held from early in 1963 until January 1968 when the raising of the pool behind the dam became imminent.

The contract for the construction of the south half of the dam was let on 9 August 1963. This $78 million contract included not only the work in the cofferdam area, but its removal, construction of the third-step cofferdam and raising of the low spillway bays, completion of the navigation lock upper si11, removal of the third cofferdam, and essentially putting the project into operation by raising of the reservoir behind the dam. The five years of concentrated effort for this second step construction; the critical third phase; the raising of the reservoir as well as the attention to the many contracts for relocation work in the reservoir area₁ was a very active period.

Localized foundation and construction problems, material and equipment supply problems, as well as difficulties with nature and man, presented themselves to be solved not only by the contractor, but by the designer, the financial experts, and Resident Engineer. The records would indicate that a well coordinated tripartite team solved the problems without materially affecting the five-year overall construction schedule for this segment of the project work.

The first concrete for the powerhouse and other structures in the second-step cofferdam was poured on 26 June 1964 and the occasion was appropriately documented by a celebration at the site. The concrete and structural work continued almost continuously until January 1967, when it was complete enough to remove the cofferdam during the ensuing three months. The next major step was to raise the 17 low bays of the spillway and complete the upstream sill and gate of the navigation lock. This required the third-step cofferdam which was closed in August 1967, right after the spring high water, diverting the entire river flow through ten skeleton bays of the powerhouse structure. Completion of this phase of the project during the third-step diversion was the most critical in the entire construction. Time was of the essence and the contractor worked six days a week during most of it and seven days at critical periods. He placed 225,000 cubic yards of concrete to raise the spillway bays during this winter period.

From January. to April 1968 the navigation lock was closed to traffic while the upper sill block was raised, and work on the lock and upper gate completed. Temporary pipelines were used to transfer petroleum products, caustics, liquid ammonia, and other chemicals around the project, to and from barges upstream and downstream. Seven eight-inch diameter lines were installed with appurtenant pumps, valves, and fixtures serving two separate docks above and three below the dam. No provision was made to handle dry bulk commodities, such as small grains.or miscellaneous cargoes.

Fortunately, streamflows and weather conditions were fairly favorable that winter, and all was in order on 16 April 1968 to close the intake gates to the ten skeleton power units in the powerhouse and start the impoundment.

The filling of the reservoir was not just simply closing the outlet spigot and letting the bucket fill up. The date for the filling was a three-way compromise. The contractor would have liked more time to accomplish the preparatory work. The fishery interests were very concerned over the early spring runs salmon and wanted the filling action out of the way by the last of March. In addition, they felt strongly that the initial filling should take no more than three days because of the complete block to the fish movement. The navigation interests, of course, were more than anxious to complete the work and eliminate the impediments. The critical factor, however, was water, and when it would be available naturally, or in a sufficient quantity from some artificial source.

The 77-mile-long reservoir contains better than 2,000,000 acre-feet of stored water. Mid-April was considered about as early as adequate natural flows would be available. Knowing this would still not be sufficient to fill the reservoir in the time required for the anadromous fish, releases from upstream reservoirs had been negotiated with the Bureau of Reclamation, Idaho Power Company, and Bonneville Power Administration. Water releases to arrive in the John Day reservoir during the three-day schedule were carefully planned. Storage from nine projects was released from 10 to 50 hours ahead of the zero hour. Those projects contributing to the success of the venture were:

Albeni Falls                      245 ,000 A.F.

Duncan (Canada)                35,000 A.F.

Kootenay Lake                  44 ,000 A.F.

Grand Coulee                   360,000 A.F.

Chief Joseph                      81,000 A.F.

Wells                               314,000 A.F.

Brownlee (Idaho Power) 113,000 A.F.

Ice Harbor                        20,000 A.F.

McNary                          180,000 A.F.
______________
1,112,000 A.F

The natural flow of the river did the rest. Since it was actually a below-average flow, the filling required an extra day to put the fishways into operation.