Wednesday, August 14, 2013

How Deep is My River Part 3

The long and difficult project of making a shipping channel from Portland to the sea involved a lot more than simply dredging. As anyone knows who has played in the mud as a kid, channeling water to go the way you want it to go involves building dikes and dams as well. From the lower Columbia all the way to the Portland harbor the Army Engineers erected these dikes and dams in places where the water could be directed in a way to make the channel deeper, and to insure that the flow of the river would keep the channel from silting up. Before these efforts the charts of the river would change dramatically over the course of several seasons of the rivers fluctuating from the late summer and early autumn low water to the floods of the spring freshet. Sand bars would appear where there were none before and large snags dragged downstream by the current would create barriers and hazards.

A dam at the Willamette's mouth

The U.S. Army Engineers operated several snag boats to deal with the roots of mighty forest giants washed into the sand by river currents. This is a picture of the snag puller, Mathloma.
Besides dredging, and building dams and dikes, the Army Engineers used a method of channel deepening they called "propeller sluicing." This could be carried out in areas where the river bottom was made from hardened silt and sand. A riverboat with special propellers would stir up the sand at the river bottom and pull a system of drags over the slurry to bring it into the river current where it would be carried downstream to settle in deeper pools and troughs.
Propeller sluicing at St Helens


A U.S. Coast Survey chart from 1851 shows the original depths, in feet, of the beginning of the river channel above Astoria. This was the area where the original discoverer, Robert Gray, turned back after briefly running aground.



 By the 1890s dikes and dams ran along the rivers from Portland to the sea. Here are some images from an 1894 map of Portland showing the dikes along the Portland harbor and on to St Johns. The dike running from the lumber mill in northwest Portland to Swan Island acted as a harbor wall for a large community of "scow dwellers" on both sides. They used the dike as a walkway to access their houseboats.
Dike from lumber mill to Swan Island

Dike below Saint Johns

River channel by Swan Island (appx 25 feet deep)


The dike in front of North Pacific Lumber mill as seen from Portland Flouring Mills


 In anticipation of the completion of the Panama Canal the Port of Portland developed a remodel of the entire harbor. The original wharves were razed and a seawall constructed. The larger wharves were already operating north of the city, or across the river in lower Albina by that time. The river channel was moved to the west side of Swan Island, and a large system of docks was proposed for Mock's bottom and Saint Johns.


It seems to me that there is no financial incentive to dredge the Willamette deep enough to accommodate ships designed for the new Panama Canal channel opening in 2014-especially with the industrial waste superfund sites preventing normal dredging. This is a subject that would take me far too long to do justice in my little blog. I am so immersed in the old days that I recently realized that dyke (as seen on the maps) is now spelled "dike." I am probably the wrong person to write about the present state of affairs, or those to come.

I won't be here to see much of what will happen, but it seems  that Portland harbor is sliding into the shadow of larger Columbia river grain terminals and larger Pacific Coast docks. Maybe the best use of these old dockyards would be to invite the scow dwellers back. That would surely humanize these sad areas of desolation that one sees as one travels down the river from Alber's Mill to Kelley Point. Finally, it goes almost without saying, we should rebuild the old Willamette River Light Station. What good is a river mouth, obscured by the fog, without a bungalow on stilts shining its light into the mist? Once the industry is gone Portland will need to survive by being a place of unique weirdness to attract future generations of hipsters.




Willamette River Light Station