Sunday, August 7, 2011

Puget Sound

Puget Sound (Pew-jut sound) is a sound in the state of Washington.

It is a complex estuarine system of interconnected marine waterways and basins, with one major and one minor connection to the Strait of Juan de Fuca and the Pacific Ocean — Admiralty Inlet being the major connection and Deception Pass being the minor.

Flow through Deception Pass accounts for about 2% of the total tidal exchange between Puget Sound and the Strait of Juan de Fuca.[1] Puget Sound extends approximately 100 miles (160 km) from Deception Pass in the north to Olympia, Washington in the south. Its average depth is 205 feet (62 m) and its maximum depth, off Point Jefferson between Indianola and Kingston, is 930 feet (280 m). The depth of the main basin, between the southern tip of Whidbey Island and Tacoma, Washington, is approximately 600 feet (180 m).

The term "Puget Sound" is used not just for the body of water but also the general region centered on the sound.

George Vancouver explored Puget Sound in 1792. Vancouver claimed it for Great Britain on 4 June 1792, naming it for one of his officers, Lieutenant Peter Puget.

After 1818 Britain and the United States, which both claimed the Oregon Country, agreed to "joint occupancy", deferring resolution of the Oregon boundary dispute until the 1846 Oregon Treaty. Puget Sound was part of the disputed region until 1846, after which it became US territory.

American maritime fur traders visited Puget Sound in the early 19th century.

The first European settlement in the Puget Sound area was Fort Nisqually, a fur trade post of the Hudson's Bay Company (HBC) built in 1833.[11] Fort Nisqually was part of the HBC's Columbia District, headquartered at Fort Vancouver. The Puget Sound Agricultural Company, a subsidiary of the HBC, established farms and ranches near Fort Nisqually. British ships such as the Beaver, exported foodstuffs and provisions from Fort Nisqually.

The first American settlement on Puget Sound was Tumwater. It was founded in 1845 by Americans who had come via the Oregon Trail. The decision to settle north of the Columbia River was made in part because one of the settlers, George Washington Bush, was considered black and the Provisional Government of Oregon banned the residency of mulattoes but did not actively enforce the restriction north of the river.

In 1853 Washington Territory was formed from part of Oregon Territory. In 1888 the Northern Pacific railroad line reached Puget Sound, linking the region to eastern states

Low Tide Whidbey IslandThe United States Geological Survey (USGS) defines Puget Sound as a bay with numerous channels and branches; more specifically, it is a fjord system of flooded glacial valleys. Puget Sound is part of a larger physiographical structure termed the Puget Trough, which is a physiographic section of the larger Pacific Border province, which in turn is part of the larger Pacific Mountain System.

Puget Sound is a large salt water estuary, or system of many estuaries, fed by highly seasonal freshwater from the Olympic and Cascade Mountain watersheds. The mean annual river discharge into Puget Sound is 41,000 cubic feet per second (1,200 m3/s), with a monthly average maximum of about 367,000 cubic feet per second (10,400 m3/s) and minimum of about 14,000 cubic feet per second (400 m3/s). Puget Sound's shoreline is 1,332 miles (2,144 km) long, encompassing a water area of 1,020 square miles (2,600 km2) and a total volume of 26.5 cubic miles (110 km3) at mean high water. The average volume of water flowing in and out of Puget Sound during each tide is 1.26 cubic miles (5.3 km3). The maximum tidal currents, in the range of 9 to 10 knots, occurs at Deception Pass.

The Puget Sound system consists of four deep basins connected by shallower sills. The four basins are Hood Canal, west of the Kitsap Peninsula, Whidbey Basin, east of Whidbey Island, South Sound, south of the Tacoma Narrows, and the Main Basin, which is further subdivided into Admiralty Inlet and the Central Basin. Puget Sound's sills, a kind of submarine terminal moraine, separate the basins from one another, and Puget Sound from the Strait of Juan de Fuca. Three sills are particularly significant—the one at Admiralty Inlet which checks the flow of water between the Strait of Juan de Fuca and Puget sound, the one at the entrance to Hood Canal (about 175 ft/53 m below the surface), and the one at the Tacoma Narrows (about 145 ft/44 m). Other sills that present less of a barrier include the ones at Blake Island, Agate Pass, Rich Passage, and Hammersley Inlet.

The size of Puget Sound's watershed is 12,138 sq mi (31,440 km2).[2] "Northern Puget Sound" is frequently considered part of the Puget Sound watershed, which enlarges its size to 13,700 sq mi (35,000 km2).[18] The USGS uses the name "Puget Sound" for its hydrologic unit subregion 1711, which includes areas draining to the Puget Sound proper as well as the Strait of Juan de Fuca, the Strait of Georgia, and the Fraser River.[19] Significant rivers that drain to "Northern Puget Sound" include the Nooksack, Dungeness, and Elwha Rivers. The Nooksack empties into Bellingham Bay, the Dungeness and Elwha into the Strait of Juan de Fuca. The Chilliwack River flows north to the Fraser River in Canada.

Tides in Puget Sound are of the mixed type with two high and two low tides each tidal day. These are called Higher High Water (HHW), Lower Low Water (LLW), Lower High Water (LHW), and Higher Low Water (HLW). The configuration of basins, sills, and interconnections cause the tidal range to increase within Puget Sound. The difference in height between the Higher High Water and the Lower Low Water averages about 0.3 feet (0.091 m) at Port Townsend on Admiralty Inlet, but increases to about 14.4 feet (4.4 m) at Olympia, the southern end of Puget Sound.

Puget Sound is generally accepted as the start of the Inside Passage.

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