“Past Horizons”
McNary Dam Newsletter, “The Sage Hen,” circa 1951

Then came the floods of ’48. Vanport washed out – screamed all headlines. Up and down the Columbia, reports were coming in of the terror and havoc being raised by the scurrying, rampant river. Memorial day, in Umatilla found all Corps personnel and volunteers from the surrounding communities battling the rising water tides and beat back the flood with what is now called “The Miracle mile Dyke.” Hundreds worked untiringly without days of sleep to throw up the mound of protective dirt covering the wide expanse of the Umatilla beach. Homes were saved, and thousands watched the slowly receding ribbon of water with anxious eyes.

But what of North McNary? As the river rose, those in charge gave the word to flood the now completed cofferdam and the long encirclement of steel cells soon disappeared beneath the rushing waters of a now angered Columbia. Later the report on the Washington shore read:

With minor dirt fills to the shore arms of the first stage cofferdam completed, unwatering of the interior of the huge structure is underway by the Corps of Engineers. Two, 20-inch turbine pumps capable of moving 12,500 gallons each per minute through a 24 inch dredge pipe-line was expected to complete the task before the awarding of the second major contract on July 20th.

The cofferdam cells, forming a steel-spearhead thrust into the surging Columbia,

were undamaged by the flood waters. At present they are being freed of logs and debris.

Crews under the direction of Paul A. Nelson, construction superintendent, have built a wooden weir near the flood-gate structure on the downstream shore arm, on which are located the two electric pumps. The pumps are running on a 24 hour schedule, which the Corps of Engineers officials estimate will empty the structure within a week.

The pumps, with a rated capacity of 12,500 gallons per minute at a 25-foot head, have not pumped less than 11,000 gallons per minute.

Initial measurements showed a 30 inch lowering of the water level in 18 hours. Pumping will remove an estimated 500 acre feet of water now contained by the coffer dam. Cost of unwatering the enclosure has been estimated at $8,000. Fish caught behind the steel-celled rock filled walls will be netted by engineer personnel, placed in tubs and returned to the Columbia a few feet away.

Flooded by the Corps of Engineers during the recent high water to save the structure July 20th will find the vast interior of the first stage cofferdam in top condition for resumption of work by the contractor receiving the bid on that date. . . The next phase, construction of the locks, fishladder and 13 spillway piers on these shores. . . . and build them they did!! . . . . . . . . . .