UU 5. IMPROVEMENT OF THE MOUTH OF COLUMBIA RIVER, OREG. AND WASH. For history of this work, projects, and results accomplished, see current summary of this report. OPERATIONS DURING FISCAL YEAR 1911. At the beginning of the fiscal year the jetty tramway had been constructed to station 340+60, bent 1979, and the enrockment had been extended to station 337 +18, bent 1960. During the first half of the fiscal year the tramway was extended from station 340+60, bent 1979, to station 358+78, bent 2080, of which 74 bents were taken up, making the end of tramway at station 345+46, bent 2006. No trestle was lost during the winter storms of the present fiscal year, and in the spring that portion which had been taken up was rebuilt to station 355+72, bent 2063, which was the end on June 30, 1911. Besides this extension about 400 piles were driven to strengthen the older parts of the trestle. During the year a total of 660,070 tons of stone were received from the Columbia Contract Co., under contracts dated October 21, 1909, and September 16, 1910, and under open-market purchase, all at the price of $1.12 per ton. The delivery of stone has been regular and the quantity received during the last months of the fiscal year has been very satisfactory. The enrockment was extended from station 337 +18, bent 1960, to station 358 +60, bent 2079. A large portion of the stone received was used in raising the enrockment between station 211+08, bent 1255, and station 337 +18, bent 1960, which accounts for the comparatively small extension beyond the end of the preceding year. This process of feeding the slopes was made necessary during the past two years on account of the rapid extension in previous years, but has now become so reduced in amount that nearly all the stone to be received during the coming fiscal year can be used in extension. The usual winter storms were experienced, but no loss of trestle resulted, although some damage was done to it. This result is due no doubt to the fact that 74 bents at the outer end, which were used for placing an apron, were taken up, and also on account of greater strength of the structure. During the winter of 1910 a large amount of work was done in deepening slip at Dock A, which had become filled with stone and mud. A "Williams" bucket equipped with teeth was used and found very efficient, as it handled both the muck and stone of all sizes. An infirmary was built at Fort Stevens and equipped for use in caring for injured engineer employees. Considerable repairs were made on such buildings as needed it. These buildings at Fort Stevens were originally of the cheapest construction, and many of them have almost reached the end of their serviceability. During the winter the derricks were overhauled and new parts installed where needed. Model barge A was put in thorough repair at a cost of about $2,900. A larger tank was erected at the Sands and preparations made for the erection of a new 20,000-gallon tank near the wells. The only additions made to the plant during the year were one Porter locomotive and two boilers for Mundy engines; also two generating sets, the latter by transfer from the fortifications. One of the sets has been installed and the shops fitted up with motors. The change from steam to electricity in the shops is proving very satisfactory and economical. Some minor additions of machines were also made to the shops. The tracks had much necessary work done to them during the winter months, including the renewal of rails from station 211+98, bent 1260, to station 258 +24, bent 1517. The deteriorating effect of the salt water and air is very great and a very large number of angle bars and bolts had to be renewed. All the machine work required for repairing plant was done in the shops; also a large amount of work in connection with the defenses at the mouth of the Columbia River and for the dredges. Material for 20 new dump cars has been purchased and work commenced on them. The bar survey was commenced on June 7 and completed on June 16, 1911. Weather conditions were good for sounding. The survey shows a general movement of the opening through the bar about 2,500 feet to the northwest and a movement of the channel through this area of about 3,500 feet in the same direction. The width of this opening through the bar between 24-foot contours has remained practically unchanged, being approximately 8,000 feet, with the exception of two small lumps where depths of 24 feet or less were found. The controlling depths across this area from deep water inside to deep water outside vary from 25 feet to 27 feet. There are two narrow channels with a least depth of 27 feet and one channel, lying between these, with a least depth of 27 feet, which is an increase of 1 foot over the maximum controlling depth across the bar found in 1910. Immediately inside the bar many changes have taken place. An extensive deep-water area has developed with depths of from 30 to 35 feet extending from the end of the jetty to the southeasterly end of Peacock Spit, while immediately east of this deep-water area and lying between it and the inside 30-foot contour considerable shoaling has taken place, amounting in places to 6 feet. This 30-foot contour has receded about 2,500 feet. Peacock Spit along its ocean front shows small changes. There has been a slight advance of the 24-foot contour along the southerly portion and a recession along the northerly portion. On the south side the extreme point, which controls the width of the opening across the bar, has receded about 2,500 feet. Inside the bar the 24-foot contour of Peacock Spit has advanced for a considerable distance and has receded slightly along Republic Spit south of Sand Island. The extreme northerly 24-foot contour of Clatsop Spit has advanced for a considerable distance, to an extent about equal to the recession of the 24-foot contour on Republic Spit on the other side of the river, and west of this advance it has receded, again conforming in direction to the movement of the same contour on the other side of the river. South of the end of the jetty the 24-foot contour of the extreme western point of Clatsop Spit has advanced about 2,000 feet, while the southerly contour has changed little. The results shown by the survey are, on the whole, most satisfactory. There are evidently great changes taking place, most of which can be classed as favorable. The formation of the shoal inside the bar can not yet be considered as the beginning of a permanent obstruction, as it is probably due to causes which will disappear as the jetty advances and the equilibrium which has been disturbed becomes readjusted. One of the most promising features is the fact that the bar is pitted with deep holes, indicating that at any time a deeper channel than now exists may develop. During the past year the dredge Chinook worked on a line passing about 1,000 feet northwest of buoy No. 2 toward the mid-channel buoy. This line was in the deep water as shown by the survey of 1910, but owing to changes caused by jetty extension it is now shoaler than before dredging was commenced, while the deepest water is now over half a mile to the northwest. The 24-foot contour at the westerly point of Clatsop Spit is now within 500 feet of the line of dredging, which shows a minimum depth of 25 feet with 241 feet 500 feet to the west and 23 feet 500 feet to the east. A survey, extending from Canby Light to Megler, was made in January for the purpose of securing data to determine the best plan. for the construction of the north jetty. The survey included the shore line and soundings in Bakers Bay, all of Sand Island, and some topography at Fort Canby. The repairs and alterations of the dredge Chinook, under contract dated January 6, 1910, with the Marine Iron Works of Portland, were completed August 25, 1910. The work included a thorough overhauling of boilers, installation of fuel-oil burning system, entire removal of hurricane deck, saloon deck, and most of the spar deck, lowering all pumping machinery, pipes, etc., one deck, thereby materially reducing her draft. The dredge was put in commission on September 20, 1910, and commenced work on the Columbia River Bar. From the above date until December 14 the dredge worked on the bar 19 days and in the channel below Astoria 33 days (working here when the bar was too rough), and removed 59,756 cubic yards and 113,363 cubic yards of material, respectively, at these localities. During that period much time was lost through the constant breaking of the suction pipes while working on the bar. The suction pipes were equipped with ball and socket joints and slip joints, the latter placed near the drag heads. On December 14 the crew was reduced and the dredge laid up at Flavel Dock on account of all the suction-pipe elbows on hand having been broken. On January 23 she was again put into commission for work on the ship channel of the lower Columbia, and continued operations there until April 14, when preparations were commenced for beginning work again on the bar. These preparations which included installation of new liners and the replacing of the ball and socket joints and slip joints by rubber suctions, were not |