APPENDIX Q Q. IMPROVEMENT OF RIVERS AND HARBORS IN OREGON, AND IN WASHINGTON TERRITORY-CONSTRUCTION OF CASCADES CANAL, COLUMBIA RIVER-IMPROVEMENT OF LOWER CLEARWATER RIVER, IDAHO. REPORT OF CAPTAIN CHARLES F. POWELL, CORPS OF ENGINEERS, OFFICER IN CHARGE, FOR THE FISCAL YEAR ENDING JUNE 30, 1884, WITH OTHER DOCUMENTS RELATING TO THE WORKS. 14. Lewis, Humptuleps, and Dwamish rivers, Washington Territory. UNITED STATES ENGINEER OFFICE, Portland, Oreg., July 30, 1884. GENERAL: I have the honor to transmit herewith my annual reports upon works of river and harbor improvements under my charge for the fiscal year ending June 30, 1884. Very respectfully, your obedient servant, The CHIEF OF ENGINEERS, U. S. A. CHAS. F. POWELL, Captain of Engineers. Q Q.1. IMPROVEMENT OF LOWER WILLAMETTE AND COLUMBIA RIVERS, OREGON AND WASHINGTON TERRITORY. The project consists in contraction of water-way by low dikes and cutoff dams and in-shore protection for improvement of the channels at the 4 bars from Portland to Saint Helen's, Oreg.; in dredging and stirring up the bottom at these bars during construction of permanent works, and also at shoal places below Saint Helen's, and in snagging operations. The original estimate of the cost of the permanent works is $298,974. The total appropriation since adoption of the present plan, in 1877, is $367,000; of this amount about $175,000 have been expended upon the permanent works. The estimate for completion of these works is derived as follows: Saint Helen's dikes, not commenced, original estimate.. Swan Island dike, not commenced, modified project (1879), proportionate cost of whole to contract awarded (1879) for partial length... Ten per cent. thereon for contingencies and inspection... Completion of auxiliary works commenced at head of Willamette Slough and on left bank at Post-Office Bar.. $97,440 54,950 5,495 25,750 183, 633 Total... The reasons for excess of cost and estimate for completion over the original estimate are addition of works to attain the object as required in late years, viz, a channel navigable at low water by long vessels drawing 20 feet, calling for a wider and deeper channel than first contemplated; extension of shore protection on account of much increase of caving of banks caused by the greater number of deep-draught vessels and river craft; and inadequacy of appropriations which has not permitted economical work. Completion of the permanent works was provided to be made in two years, while actual work on one-half of the structures has extended through five years. The cost of temporary improvement and maintenance naturally varies according to exigencies, for next year it is estimated as follows: Operating dredge-boat with tender for six months...... Transfer of snag-boat Corvallis from improvement of Upper Willamette $10, 800 6,500 10,500 Hire of steamship for bar sluicing. 4.200 10,000 3,000 10,000 55,000 5,500 Preservation of unfinished works and care of plant during suspension of operations Contingencies... Total....... 60, 500 Cost of temporary improvement, other than snagging, is the estimate for requirements below Saint Helen's, as it is expected that permanent works above will have been sufficiently advanced by another year to dispense with dredging. Temporary improvement of the river shipchannel is unsatisfactory and sometimes uncertain; it cannot be applied until a low stage is approaching, requires much time, and causes a part blockade of the channel during continuance, gives temporary relief only, and at an increasing yearly cost as the shipping increases. The navigation interests of the Columbia River have now reached such dimensions by greater numbers and tonnage of sea going craft, that a better channel on the tidal sections than can be afforded by temporary methods at reasonable cost is justly demanded. Below Saint Helen's are three principal bars, two shoal places and one rock obstruction; the cost of the removal of the latter is roughly estimated, in absence of a survey, as $60,000; permanent works at the other obstructions and needed measures for stoppage of bank caving will probably cost as much as the works above Saint Helen's will have cost, or about $360,000, making a total of $420,000 for application below the reach now provided for in the estimates based on the project of 1877. The work could be profitably completed in two years, requiring only thereafter a small amount for maintenance and snagging. OPERATIONS DURING THE YEAR. A small balance of the appropriation for the preceding year was retained for snagging, preservation of unfinished structures, and urgent temporary work. The June high water was an unusually small one, but with the average rate of recession this hastened the time of low water, whose duration was prolonged by a remarkable absence of rain freshets. The very low water and suspension of operations caused trouble at the worst bars, except at the mouth of the Willamette, which was the only place where permanent works had been applied. Difficulty at Post Of fice Bar was decreased, but not wholly removed, by partly built works. By late July the channel of Saint Helen's carried only 12 feet, reduced, the local gauge reading 5 to 4 feet, and the river steadily falling; vessels had grounded here and all deep craft had commenced to lighten; 17 feet, reduced, was found at Walker's Island; 14 and 17 feet, reduced, at Swan Island and Post Office. Search was made for a new channel at Walker's. Two feet more depth on a tortuous line was found on the opposite side from the old channel. It was marked by temporary ranges. The pilots kept to the old channel, however, because straighter and of greater depth than at some other places. It was expected that Post-Office Channel would improve by scour of Willamette freshets; the weak rises of that river, however, and want of completion of the works for contraction did not add more than 1 foot to the channel depth. SAINT HELEN'S BAR. An offer of $2,500, and the use of the snag-boat as tender for moving anchors and other work, was made for propeller sluicing under specifi cations. The work was undertaken by the management of the steamship lines on the Columbia River, for some additional compensation, however, given by the Portland Board of Trade. The channel was sluiced out during eight days in August by the steamship Walla Walla, giving 20 feet at zero of gauge, and for a width of 150 feet. The length of cut was about 1,600 feet; material removed was estimated as 35,000 cubic yards. The actual working time was about sixty-eight hours, and the coal consumption 244 tons. The channel remained good during the shipping season. Some filling was reported in April, but the summer rise followed shortly, which will have postponed trouble until next August. The method of sluicing is the same as used here in the previous year, and as described, and the history of its introduction given, in the report for that year. Propeller sluicing is now a recognized method for temporary improvement on the Columbia River. A sketch is attached herewith, showing the operation. Mr. John Gates, who is the engineer of the company's river division, and was agent in charge of the sluicing, has designed a vessel for such special work, and also adapted for towing. The craft is a large tug, which can be readily depressed at the stern, with powerful machinery, and two inclined spuds, attached by ball and socket joints to a post built in the forward frame. The spuds are to keep the boat from moving ahead when sluicing, and to permit swinging of the stem on the bow as a pivot. SWAN ISLAND BAR. The Osgood dredge commenced August 9 on the line of cut of 1882, worked down stream from opposite the five-pile beacon, crossing the crest of the bar, and carrying the cut to the 18-foot curve on the downstream slope. The dredge was then (October 10) moved to the head of bar and engaged in straightening and widening the entrance, and in removing a ridge in advance made by sunken drift, which had lodged across a deep part of the bottom at a narrow place. At the end of October the dredge was withdrawn, from want of funds. The digging was on a width of 90 feet, with a flaring outward at the head and to a depth of 21 feet at zero of gauge. The following is a summary, of work: Number of days on which dredging was done Greatest number of yards in one day Average number of yards per day... Work commenced August 9, 1883; closed October 30, 1883. 68 29,445 685 433 The material was sand, gravel, clay, harbor refuse, and sunken or imbedded tree trunks and stumps. The endless chain dredge owned and operated by the city of Portland, commenced work in August at the lower end of the bar, advancing up stream until the shoal area of 18 feet was reached. She then moved to near the 3-pile beacon, and widened the cut on the west side, where the channel changed a little in direction; this left a shoul der in the bank on that side, against which a fill was made during the next river rise. The city dredge did not dig deeper than about 18 feet at zero, and broke down frequently whenever hard digging was encountered. Subsequently and after the winter freeze-up the dredge worked deeper and to better advantage in loose gravel at the extreme head of the bar, where she widened the channel, and also in the late spring, near the lower 5-pile beacon, where the digging was in sand. In November and December the Osgood dredge scows and tender were worked by and at the expense of the Oregon Railway and Navigation Company on the entrance to their new dry-dock, as authorized by the honorable Secretary of War. The following is a summary of this work: Number of days on which dredging was done. Number of cubic yards excavated.. Greatest number of yards in one day Average number of yards per day. Material, clay and gravel. Work commenced November 9, 1883; closed December 26, 1883. 35 15,700 600. 449 In January, February, and first week of March, the dredging fleet was worked by the Portland Flouring Mill Company, at its expense, in wharf dredging, as authorized. The following is a summary of such work: Number of days on which dredging was done Greatest number of yards in one day Number of cubic yards excavated.. Average number of yards per day.. Material, clay. Work commenced January 7, 1884; closed March 3, 1884. MAINTENANCE OF STRUCTURES AND SNAGGING. 37 19,800 800 535 After the Saint Helen's sluicing, the snag-boat was used during about ten days for repairs of structures for river improvement; examinations of changes by last summer's high water, and removing snags from the channels. The boat was put in commission for similar service for a week in November, and also ten days in April. A shallow breach 90 feet long in the Pearcy's Slough Dam, made in June, 1883, was closed with brush work. In April a number of groins, 45 to 60 feet long, were placed about 10 feet apart along those portions of the dam and banks where protection against erosion was needed; 327 bolsters, averaging 2 feet by 14 feet, made of saplings, were used in the groins. In November a quantity of heavy drift was removed from the Willamette Slough Dam, fascines along face of Sauvie's Island revetment, which had been disturbed by swell of steamships, were replaced and ballasted; a light brush revetment was laid and willows planted on 300 feet of beach adjoining the south end of Coon Island Dam where erosion had commenced. Willows were also planted on the Pearcy's Slough Dam, and a small shore revetment added on east bank below the dam. The Corvallis pulled nine snags from the channels during the above times; and the tug Lincoln, when in service as a tender to the dredge or on river examinations, removed twenty-nine. The estimates provide for the transfer of the snag-boat from the Upper Willamette, to which improvement she belongs, and also for a new hull. The Corvallis is the only snag-boat on the rivers near Portland; she has worked all around where her services were most needed on the upper river, on the lower river and the Columbia; and on the Cowlitz, a length of river of 270 miles. Postponements and curtailing of work and expense of long trips are results of this arrangement. Her machinery is better adapted for a boat on the lower river than on the upper river. A new boat should be stationed above the falls and be readily available for full snagging and scraping required there. BRIDGING THE WILLAMETTE RIVER AT PORTLAND. Nothing was done during the year in removal of the piers and bents of the unfinished Morrison Street Bridge. These obstructions remain · as a continued menace and danger to the navigation of this part of the river. An appeal from the decree of the circuit court, ordering a perpetual injunction against the construction has been taken to the Supreme Court. Soundings on axis of the bridge, made July 17, 1884, by Assistant Habersham, show the following changes in profile of bottom since December, 1880, the time of placing the piers. Span No. 1 (on left bank of river), a gain in depth on the east side of the span of 5 feet, and on the west half a filling of from 5 to 9 feet. Span No. 2, a gain of 19 feet in the center. Span No. 3, a gain of 26 feet in the center. Span No. 4, a gain of 15 feet in the center, and 18 feet near east support pier. Span No. 5, a gain of 8 feet on west half of span. From No. 5 to right bank of river the change of profile is small. Around the basis of the piers, which are protected by riprap, no erosion appears. Soundings on a line parallel to and 50 feet below the axis show: Opposite span No. 3, 6 feet deeper. Opposite span No. 4, 7 feet less. On this line, below the piers, the general gain in depths corresponds with that on the axis, except below the pivot pier, where it is about 5 feet less. No shoaling is found at any point, except along the left bank, as above noted. |