W&7/ MIINinfP" P^S - 3 K 5 E M E UIMM M CHITTENDEN LOCKS «n U S ARMY K 1 CORPS OF ENCINEERS J t 1 m. ^fc y ^ •**A gig '4 m ST 3* *3? ".* 627.13509 f V831 J U i *lfc v^r*** LAKE WASHINGTON SHIP CANAL AND LOCKS encourage rapid growth of recreational boating as well as fishing and commercial-vessel traffic. Aerial photo at left, by The Post-Intelligencer, shows pleasure craft assem­ bling in the canal and Portage Bay for the annual yachting parade...Above are boats moving out of the small lock to cruise on Puget Sound...Shilshole Bay's small-boat basin (right), adjacent to the entrance of the canal, is a co-operative undertaking by the Fed­ eral Government and the Port of Seattle. OTHER RIVER AND HARBOR and Flood-Control work of the Army Engineers' Seattle District is represented by the projects shown on this page. At left Is Howard A. Hanson Dam, a new flood-control project in Eagle Gorge of the Green River in western Washington...Above Is the Army Engineer's Snagboat W. T. Preston which helps keep Puget Sound harbors and navigable rivers of West­ ern Washington free of logs and other hazards...Chief Joseph Dam (right), on the Columbia River near Bridge­ port in north-central Washington, Is one of the United States' largest power producers. UsV CANAL OPENS INLAND HARBOR some means were not provided to return the salt water and In the small lock, 123 feet. The large lock's cham­ to the lower pool. To meet this difficulty, a salt­ ber is 80 feet wide and the small one 28 feet. The Lake Washington Ship Canal, lying wholly wlth- water basin, about 2,000 feet long and 250 feet wide, The larger lock's walls are 55 feet high above the with its bottom elevation 12 feet lower than the ele­ floor and the small lock's 42 feet high. Vessels going vation of the upstream miter sill, was dredged Immedi­ through the locks from salt water to fresh water, or Unlon and Lake Washington. All have the same level and ately above the large lock. From the lower end of this vice versa, are lifted or lowered between 6 and 26 feet. are connected by free and unobstructed channels 30 feet basin a discharge conduit 30 square feet In cross sec­ The exact raise depends upon the tide in the Puget Sound deep at low lake level. This Inland harbor has a total tion extends to the downstream side of the spillway entrance to the locks and the lake level. area of 25,000 acres and a shore line of about 100 dam. The outer end of this drain can be seen at the VESSEL TRAFFIC'S ALL-TIME RECORDS miles. It is protected from storms and Is free from dam, close to the small lock. tidal fluctuations and currents. This, together with Since these locks were opened to traffic In 1916 CULVERTS AND VALVES MOVE WATER the salt-water harbor of Elliott Bay, affords Seattle until the end of 1961, vessels passing through totaled navigation facilities which are regarded as among the The water is raised and lowered in the lock by 2,152,535. The record was 1958 when 79,396 vessels best in the United States. Prior to construction of means of culverts, one in each side wall with lat­ went through. This included 53,668 pleasure craft, the canal and locks, there was no connection between erals extending into the chamber at the floor level, 10,904 fishing boats, 7,101 tugs, 4,622 barges, 2,145 Lake Union and Lake Washington, and Lake Union had no the flow being controlled by valves. The culverts of U. S. Government vessels, 469 passenger and 240 foreign navigable connection with Salmon Bay. the large lock are 8± feet wide and 14 feet high. The vessels. There also were 366 log rafts locked through LAKE WATER ELEVATION laterals are 4 feet wide and 2 feet high. There are that year. The vessel net tons for 1958 were 3,648,679. 24 entering the upper chamber and 28 in the lower cham­ Average annual tonnage of cargo through the locks for Before construction of the locks, Lake Washing­ ber. The valves of the large lock are of the stony the last 10 years was about 2,065,000. ton's elevation fluctuated between 29 and 33 feet gate type. The valves of the small lock are of the The all-time highest month for vessel traffic above mean lower low water in Puget Sound, and Its cylindrical type. through the locks was August 1957 with a total count of outlet was at the south end of the lake through the Emergency dams are provided for both locks, to 13,811. Labor Day 1957 handled the largest single-day Black River and into the Duwamish River. Lake Union stop the flow of water In an emergency caused by some traffic when 1,189 vessels were locked through. was regulated at about Its present elevation (mean 21 accident that would permit the unobstructed flow of MORE THAN A MILLION VISITORS feet) by spillway gates at the extreme westerly end. water through the lock. Salmon Bay and Shilshole Bay were navigable at high LOCKS UNWATERED EACH YEAR Passengers through the Chittenden locks in 1958 tide, but both bays were practically dry at extreme totaled 348,512. But there's a bigger story than that The pumping plant for unwatering the locks for re­ low tide. from our shoreslde count.' Visitors from many parts of pairs consists of two 30-lnch pumps with a capacity of When the canal was constructed, a channel was the world, who came to tour the beautiful grounds and about 40,000 gallons per minute; one 10-inch pump with dredged making Shilshole Bay navigable at all times, enjoy watching the boat lockages during 1958, totaled a capacity of about 2,400 gallons per minute, and a 3- Salmon Bay was raised and Lake Washington was lowered 1,067,000. lnch sump pump, all electrically operated. The large to the level of Lake Union. Cedar River, which en­ Dozens of school classes come to the locks each lock is closed for a period of 12 days for annual over­ tered the Black River about one-half mile below the year on field trips as part of their social studies or haul each Fall, and the small lock has its turn for the old outlet of Lake Washington, now discharges into Washington State history courses. They travel In same purpose in the Spring. Approximately 8 hours are Lake Washington. The outlet through the Black and school buses and private cars, with teachers and par­ required to pump all water out of the large lock. Duwamish Rivers no longer exists. ents In charge. Some come from towns more than 100 Electric power for the operation of the locks is the south shore of Salmon Bay Is 240 feet long, with that annually several thousand salmon enter the canal miles away. The students then write trip reports. SPILLWAY CONTROLS LAKE ELEVATION delivered to the transformer station at 26,000 volts, six gated openings, each 32 feet long. Maximum capaci­ from tidewater. About 90 per cent of these pass Despite the great amount of water traffic and the The spillway dam and two locks, one large and and is transformed at the lockslte to 2,500 volts, 250 ty of the spillway is a flow of about 16,000 cubic feet through the locks and 10 per cent use the fish ladder. multitudes of shoreslde visitors, no serious injuries one small, about l± miles up the canal from the Puget volts and 120 volts for operating motors and for light­ per second. A fish ladder for the passage of salmon to have occurred on the locks premises in more than 20 Sound entrance, maintain the elevation of the Lakes SALT WATER RETURNED TO SOUND ing the grounds and buildings. the upper pool Is provided around the dam at the south­ years. This good record is a result of improved facil­ within the required range of 1 foot above and 1 foot LOCKS LARGE BUT NOT LARGEST Because of the difference in density between the ities and safety precautions, plus well-trained and below the normal elevation of Lake Union. ern end. fresh water above (upstream side) and the salt water Many people have the impression that these locks alert personnel on duty. The distance by channel from deep water In Puget SALMON USE THE LOCKS TOO below (downstream side) the locks, there Is always an are second only to the Panama Canal locks in size. Truth TIME AND QUANTITIES IN LOCKAGES Sound to deep water In Lake Washington is approximate- The lock and dam structures evidently offer no upstream undercurrent of salt water and a downstream Is, there are several locks In the United States larger 8 miles. The tidal reach extends from Shilshole Bay considerable obstruction to the passage of migratory surface current of fresh water during lockages. The than these in Seattle; but It is likely that few, If any, The average lockage through the large lock requires to the locks. The extreme tidal range is 19.3 feet. fish from salt to fresh water, or vice versa. The flow of salt water Into the upper pool eventually handle more vessels in a year. Length of the longest about 25 minutes and through the small lock about 10 The spillway dam extending from the small lock to Washington State Department of Fisheries has estimated would turn the lakes Into a salt-water reservoir If vessel which can use the large lock here Is 760 feet; minutes.