The Engineer Who Tamed the Tides: Col. Wilson’s Blueprint for Snohomish’s Future

The regular monthly meeting of the board was called to order by Hon. H. W. Corbett, president. The minutes of the last meeting were read and approved.

Further business was disposed of in order to vacate the hall and those invited as honorary members near the address.

Col. Wilson, Western, introduced by the president, proceeded to address those present for about forty minutes.

Col. Wilson’s paper referred to the subject of the improvement of tidal rivers, the operations being the Clyde and the proposed improvement of the Lower Willamette and Columbia.

He commenced by claiming that he was neither an orator nor a lecturer, but fully an engineer and soldier, and that he would place before the board of trade a simple statement of facts.

Beginning with the subject of the general improvement of tidal rivers, he gave the three divisions of a tidal river as stated by the celebrated engineer Stevenson, and announced that the Lower Willamette and Columbia, where tides occur, belong to the second section, namely, 'the tidal compartment,' where the phenomenon of ebbing and flowing is observed.

He then referred to the necessity of having a complete and elaborate survey, with all possible data, before preparing a plan of improvement, and stated that in tidal rivers the problem to be solved was to graduate the velocity of tides so no greater scouring force to the water after the channel is opened at one point than to another.

He denounced the fallacious plan of wing-dams for a tidal river, showing the damage done by them on the Clyde and on the Hudson, and claiming that by deflecting money around their ends they formed the river into a series of holes and bars.

He announced the great principle to the aim of non-interference with tides to avoid destruction, and went on to show how they should be kept up, and in such a way as to remove all obstructions from tidal rivers.

The work to be done, he said, consists in the removal of all obstructions in the natural flow of tide in the shape of 'reefs, bars, etc.,' the building of cribs of Hell-shaped and height as needed in the river only sufficient to keep open the channel, and which should guide the current in the proper direction.

Col. Wilson then discussed the satisfactory and economically feasible construction of the river banks at certain localities, and the creation of channels parallel to the flow of the current, advising low water way which the null is lowered by tides, as if it had not the natural bed to form holes and 'inlets' of purity is diminished by exposure.

Taking up the subject of Post Island bar, he described its cause, formation, given the volume of the river above it and in the channel on each side of the island, and advocated the changing of the north or Portland channel by a dam from the Head of Swan Island to the north shore, the turning of the whole volume of the river into the south channel, which he believed to be the true direction; both a channel, he thought, it ought to enable and maintain a depth of twenty feet at low water without difficulty.

Further on, he showed that not only the whole volume of the Willamette river at ordinary low water passed down the Willamette slough, but that the river between the head of the slough and the mouth of the Willamette being a dead level at this stage, a large quantity of water from the Columbia passed up the slough. To remove Post Island bar he thought the slough should be closed by a dam across its head, but as it was a navigable stream, with settlers on its banks, public interest must be regarded, and a dam could be thrown across just below the head, leaving in the middle a channel 100 feet wide and six feet deep, the sides well marked off in cribs and the bottom of protected to prevent erosion; such dam, he thought would turn seven-eighths of the water into the river proper, and not only remove Post Island bar, but materially aid in improving the bar at the mouth of the Willamette.

Moving on to the Lower Willamette, the next improvement was found at the mouth of the Willamette, where a branch of the bar showed it to be similar to that of St. Helen's bar in the Columbia. An examination of the currents during high tides on the cliff showed a large volume to pass down Coon Island slough instead of through the main channel, and that the river widened here, emptying through three channels, and that during freshets the water coming through Percy's and Columbia sloughs and filled with sediment, met that coming up the Willamette and aided materially in forming bars.

To remove this bar, he proposes to close Coon Island slough, to protect the face of Coon Island, to run a dam from Tom's Island to the main shore above the mouth of Columbia Slough to put out the love of Tom's Island and to run a dam out into the Columbia River will hold the waters of the river within reasonable limits during the low stage, and during freshets will catch behind them and keep out of the channel the sediment in suspension below the point of their toss, routing out of Percy's and Columbia sloughs such formations he believed would not only open the channel up to a depth of twenty feet at low water, but would go far to prevent the usual dredging must be done by the tides in the Columbia.

At the mouth of the Columbia, the bar was described as having a width of nearly a mile with a depth at 72% feet at low water and two tides daily with a rise of from six to nine feet; thoroughly flooded, he believed that it should be no more varied than the bar currently looks. A new harbor, 'if then referred to line Silties of dredging, described the capacity of the Dredge Firm, and gave the result of work by the permanent dredge boat in 1893, and argued the now-partially for some permanent plan for improvement.

In closing he referred to the fact that as a man he had visited this section of the country 20 years since, and after returning a year had returned again, and that after an absence of 20 years he had found conditions fit to be astounded at the growth and development of the country. He paid a high tribute to the North Pacific slope and its people, and claimed that if the increase in the next twenty years was in the same ratio as the last, Oregon would take a leading position among the older States. He argued that in the eagerness for railroads the construction of canals and the improvement of rivers should not be overlooked.

At the conclusion of the address Hon. M. P. Deady moved that a vote of thanks be extended Col. Wilson for his very able, interesting and instructive address. The motion unanimously prevailed, the board then adjourned.