Stanwell-Fletcher Lake facts for kids

Quick facts for kids Stanwell-Fletcher Lake
Stanwell-Fletcher Lake Location in Nunavut Show map of Nunavut Stanwell-Fletcher Lake Location in Canada Show map of Canada
Location	Somerset Island, Nunavut, Canada
Coordinates	72°46′N 94°48′W / 72.767°N 94.800°W / 72.767; -94.800
Type	Lake
Etymology	Named after USAAF Major J.F. Stanwell-Fletcher
Primary inflows	Stanwell-Fletcher River
Primary outflows	Union River
Catchment area	1,970 square kilometres (760 sq mi)
Basin countries	Canada
Surface area	339 km2 (131 sq mi)
Max. depth	About 100 m (330 ft)
Surface elevation	7.6 m (25 ft)

Stanwell-Fletcher Lake is the largest lake on Somerset Island, the tenth-largest island of the Canadian Arctic Archipelago. The lake, along with most of Somerset Island, is located within the Qikiqtaaluk Region of the Canadian territory of Nunavut.

Geography and hydrology

Stanwell-Fletcher Lake is located in a central area of Somerset Island that is west of Creswell Bay, which indents the eastern coastline of the island, and east of Four Rivers Bay, part of Peel Sound. A few small, unnamed islands exist on the lake. It is fed by several inflows, with the largest being the Stanwell-Fletcher River, which flows from Fiona Lake to the north end of Stanwell-Fletcher Lake. The outflow of the lake is the Union River, which flows from the eastern end of the lake to Creswell Bay, for an approximate distance of 4 km (2.5 mi). The drainage basin of the lake covers an area of 1,970 km² (760 sq mi), which is about 8% of the total area of Somerset Island. The lake itself has an area of 339 km² (131 sq mi).

Due to its tundral climate, the lake and the surrounding rivers and creeks are frozen for most of the year, allowing little flow in or out of the lake. Although when first studied in the 1960s, the lake maintained ice cover over several years, with little thawing in the summer, its ice cover, as of a 2015 study, has recently become more seasonal in nature, with more regular and intense thawing, with the most significant thawing in July and August.

Stanwell-Fletcher Lake is monomictic and isothermal in nature, with the water in the lake mixing at only one point each year, and maintaining a relatively constant average temperature of 1.5 °C (34.7 °F). The lake consists completely of fresh water, although the lake basin was previously a tidal or seasonal extension of a salt water fjord until around 2400 Before Present (BP), when it became lacustrine, and the salt water was gradually replaced through circulation.

Geology

Stanwell-Fletcher Lake is glacial in origin, with the basin it lies within being formed during the Pleistocene by glacial scouring of sediment in a Cretaceous graben. After the glacier, specifically part of the Innuitian Ice Sheet receded, the basin either became part of a fjord, connected to Creswell Bay or Four Rivers Bay, or if connected to both, became part of a strait that would have split Somerset Island. Post-glacial rebound gradually uplifted the area; by around 3500 BP the uplift had isolated the lake, although seasonal or tidal saltwater inflow from the sea continued until around 2400 BP.

The rock surrounding the lake is largely Precambrian in origin, while the rock to the northwest and underlying the lake is most likely Cretaceous and Tertiary. The topography rises steeply to the west, southwest, and northeast of the lake, while the uplifted lowland in the southeast leads to Creswell Bay, and the land surrounding the Stanwell-Fletcher River in the northwest has a more gradual slope.

Sediments at the bottom of the lake mostly consist of mud from decomposed plant material, and pebbles, although there are finer-grain sediments in the northeast, where several rivers draining the surrounding highlands have built up significant deltas. The main bathymetric feature of the lake is a u-shaped trough extending from the northwest to southeast of the lake, that reaches a maximum depth of around 100 m (330 ft). The lakebed drops steeply down to this trough in the northwest of the lake, while shallower shelves exist in the southwest and northeast.

History

Somerset Island was inhabited by Inuit or pre-Inuit cultures for large parts of its history. Remnants of Pre-Dorset and/or Dorset settlements have been found on the northwest shore of the lake, along steeply walled valleys that lead to the west coast of the island and may have previously surrounded a fjord connected to the lake.

Although the coastline of Somerset Island had been mapped by several European expeditions in the 19th century, inland areas were not extensively explored during that time period. Stanwell-Fletcher Lake was named at some point between 1943 and 1965, after USAAF Major J.F. Stanwell-Fletcher, who parachuted into Fort Ross in 1943. The jump was the first parachute jump north of the Arctic Circle, and was made to assist in evacuation efforts of the then-active trading post in the southeast of Somerset Island.