The Peace–Athabasca Delta, located in northeast Alberta, is the largest freshwater inland river delta in North America.

History

Land use and occupation by the first indigenous people in the area can be traced to the retreat of the glaciers.

In 1922, Wood Buffalo National Park was established to protect the remnant population of wood bison that escaped the slaughter in the late 19th century. It became the world's largest herd of free roaming wood bison, estimated at more than 5,000. It is one of two known nesting sites of whooping cranes.

In the late 1960s, the W.A.C. Bennett Dam was constructed on the Peace River in northern British Columbia by BC Hydro, a major hydropower utility. Between 1968 and 1971, "after the construction and initial filling of the W.A.C. Bennett hydroelectric dam at the headwaters of the Peace River", the Peace–Athabasca delta experienced a "prolonged dry period" that turned some basins from aquatic into terrestrial ecosystems.

In 1974, a major flood occurred in the region and, when the spring water receded, the delta experienced a second prolonged dry period. was created to "stem the progressive encroachment on and loss of wetlands now and in the future". They recognize the "fundamental ecological functions of wetlands" that support a "characteristic flora and fauna, particularly waterfowl"

By the 1990s, the National Water Research Institute was involved in a provincial-territorial-federal initiative, the Northern River Basins Study, and was conducting research on the hydro-climatology and ecology of the Peace–Athabasca Delta. They investigated potential impact on the delta's productivity and biodiversity if the climate were to change.

Conservation

The marshes, lakes and mud flats of this area are an important habitat for waterfowl nesting and provides a staging area for migration.

The unique location and habitat of the Peace–Athabasca Delta region supports numerous species of waterbirds and is one of the most important places in North America for migrating waterbirds to rest, feed and breed.

Although all four major North American flyways, Atlantic, Mississippi, Central, and Pacific, cross the Peace–Athabasca Delta, it is "probably the most significant to the Mississippi and Central flyways." Species include ducks, geese, swans and the endangered whooping crane, which has its natural nesting place in the delta.

The grass and sedge meadows of this area also provide habitat for several thousand wood and plains bison. Maximum flood frequency was seen to reach a maximum in the early 1900s and declined in the 1940s and 1950s prior to the construction of the dam. There were no major ice-jam floods between 1975 and 1995 and this could be a result of the dam. Major ice-jam floods occurred in 1996 and 1997. There have been similar prolonged periods lacking major flooding including 1813 to 1839 and 1705 to 1786.

Studies of the climate and ecology of the Peace–Athabasca Delta have been carried out to understand the effect of the dam on delta. It was found that the recent decades are neither the driest nor the wettest that the delta has experienced in the past three hundred years. The early 1900s were some of the wettest conditions experienced by the delta. During the early- to mid-1900s there was a general trend of drying. While the delta is drier today than it was in the early parts of the 1900s, there is no clear indication that the dam is responsible. The Peace–Athabasca Delta is still well within the range of naturally variability due to natural changes in climate seen within the past few centuries.

An ongoing lawsuit between BC Hydro and local First Nations bands relates to the effects of Bennett Dam on delta water levels and associated traditional lifestyles.

Waterways

The Birch River flows into Lake Claire, the largest lake completely in Alberta, which is an important part of the delta. Other water bodies located in the delta are Baril Lake, Mamawi Lake, Hilda Lake, Otter Lake, French Lake, Pair Lakes, Welstead Lake, Four Forks Lake, Galoot Lake, Pushup Lake, Jemis Lake, Richardson Lake, Flett Lake, Blanche Lake and Limon Lake.

Revillon Coupé, Rivière des Rochers and Chenal des Quatre Fourches are the main distributaries connecting Lake Athabasca and the point where Peace River flows into the Slave River. When the Peace River is in flood, the flow of these channels are reversed and water from the Peace flows into Lake Athabasca.

Other rivers draining the wetlands through the Peace–Athabasca Delta include Swift Current Creek, Carolyn Creek, Modere Creek, Steepbank River, McIvor River, Buckton Creek, Frog Creek, Sall River, Bolton Creek, Edra Creek, Peel Creek, Alice Creek, Mamawi Creek, Embarras River, Horse Island Creek, Chilloneys Creek, Claire River, Dempsey Creek, Baril River, Peltier Creek, Scow Channel, Powder Creek, and Revillon Coupe.

See also

  • Saskatchewan River Delta

References

  • Peace–Athabasca Delta, Geographical Names of Canada