Oswego Lake is a lake in Clackamas County, Oregon that is completely surrounded by the city of Lake Oswego. Though the lake is naturally occurring (a former channel of the Tualatin River), it has been significantly altered because of the concrete dam that has increased its size to . The United States Geological Survey records the official name as Lake Oswego and, because of its artificially increased size, classifies it as a reservoir. To distinguish it from the city, however, the lake is usually called Oswego Lake.
Geologic history
The lake is a former channel of the Tualatin River, carved in basalt to the Willamette River. Eventually, the river changed course and abandoned the Oswego route.
About 13,000 to 15,000 years ago, the ice dam that contained Glacial Lake Missoula ruptured, resulting in the Missoula Floods, which backed the Columbia River up the Willamette River. The flooding created an underwater vortex called a kolk, which scoured out and enlarged the old Oswego channel, creating a natural lake. The rocks and boulders were flung by the kolk up to a mile away to present-day Durham and Tualatin, where they were quarried for many years before the site was converted to the Bridgeport Village shopping center.
Early human habitation
The lake was known to the native Clackamas people as Waluga ("wild swan"), for the birds they hunted there. With the arrival of European settlers in the mid-19th century, the lake was called Sucker Lake for a type of fish that was abundant in its waters. In 1847, Albert Alonzo Durham built a sawmill on Sucker Creek, the lake's outlet to the Willamette River. In 1850, he made the first Donation Land Claim in the area, which he named Oswego after Oswego, New York.
Iron industry
In 1865, the Oregon Iron Company was incorporated with the goal of making the town of Oswego an industrial center for the smelting of the abundant iron ore in the area. The company purchased the entire town of Oswego, including the lake and surrounding hills, which were rich in not only iron ore, but trees that would be turned into charcoal to feed the furnaces. Population in the town boomed, aided by the opening of a narrow gauge railroad from Portland in 1886. The Oregon iron industry peaked in 1890, but with the availability of cheaper coke-fired iron and steel mills, by the early 20th century it had nearly collapsed.
Lake expansion
In 1871, the Tualatin River Navigation & Manufacturing Company began work to build a continuous waterway that would connect the Tualatin River to the Willamette. The company planned to build two canals: one to connect the Tualatin to the lake to provide access to the iron smelter, and a second with locks that would connect the lake to the Willamette via Sucker Creek. The first canal was finished in 1872, but due to low water, was not passed through until January 21, 1873, when the sternwheeler Onward made the first trip. In 1873, the completion of the Willamette Falls Locks made traffic past Willamette Falls possible without portage; since the Tualatin was more difficult to navigate anyway, the idea of a second canal was abandoned.
A series of wooden dams had been built at the outlet to Sucker Creek beginning in 1860 to provide water power; but since winter floods would wash out these dams within a few years, in 1921 a concrete dam was built, which not only provided a more reliable power source, but also allowed the lake level to be precisely controlled. The level was allowed to rise several feet to cover the unsightly stumps left over from logging and create a more visually appealing shoreline.
With the name Sucker Lake considered unappealing to potential residents, the community decided to rename the lake. While "Lake Tualatin" was considered, in 1913 the United States Board on Geographic Names officially renamed it Oswego Lake. In 1961, the USGS officially changed the name to "Lake Oswego," though the old name is usually used to avoid confusion with the name of the city.
In 1928, a marshy area known as the Duck Pond adjacent to the lake was flooded, and a canal dug to it to connect to the main lake to create Lakewood Bay, which allowed more shoreline homes to be built next to the newly completed Pacific Highway (now part of Oregon Route 43).