Early in the spring of 1962 the noise of a large motor was heard below East Grand Avenue. It was the pump used to dredge the sand from the Snohomish River. The sand was piled in a huge mound...many feet high...piled to drain on the flatland which over the years had grown up with trees and scrub. After the water had drained out, the dry sand was used in the surfacing of the Freeway I-5.
Being flat and clear again the logs began to appear o the waterfront and the mills started once more to shave and cut the log into the desired lumber.
Every day of the year we look across these flatlands to the mountains...always changing...sometimes there is snow and the occasional snow storm, often clothed in mist, giving way to shimmering heat and the colorful reflections of the sunset. 
I-5 is completed in Washington on May 14, 1969
The final segment of Interstate 5 in Washington State stretched four miles, from the southern end of Marysville to the northern edge of Everett at the Snohomish River. The four-mile section cost $9.8 million (approximately $58 million in 2010 dollars) to build, and included 11 bridges in its short stretch. More than 1.7 million cubic yards of dirt was moved during its construction. In April 1969 the northbound lanes of this section opened to traffic. The southbound lanes opened on May 14, 1969. The last traffic light on the freeway (located on temporary I-5 at Walnut Street in Everett) between Canada and California was symbolically taken down when the new segment of freeway opened at 11 a.m. [2, 3]
WSDOT Opening Day Celebration Material: Everett Freeway (I-5) Opening January 18, 1968
1. Riverside Remembers II, page 175.
2. Interstate 5 is completed in Washington on May 14, 1969, by Phil Dougherty www.historylink.org/index.cfm?DisplayPage=output.cfm&file_id=9393
3. WSDOT Opening Day Celebration Material: I-5 Snohomish River - Marysville Opening May 14, 1969 https://cdm16977.contentdm.oclc.org/digital/collection/p16977coll3/id/210/rec/3