Alberta's World Famous Delta
Many times when rivers flow into large bodies of water or other rivers, a large deposit of silt and soil can collect at the mouth of a river. Also, shallow bodies of water may develop during the high flow periods. When this occurs, that area is known as a delta. Deltas are continuously changing and reshaping the landscape on which they are found.
The largest inland freshwater delta in the world is located right here in northern Alberta. The delta of the Peace-Athabasca river system is a
wetland area of international importance where thousands of birds come to nest, including the internationally threatened whooping crane. The entire delta is alive with a diversity of life that depends on the Peace and Athabasca Rivers to bring in nutrient-rich sediment. The sediment washes over the delta in a yearly flood cycle. Huge volumes of
sediment are carried by the rivers as they carve their way northward and settle out as the rivers reach the flatlands of the delta. Every spring, the rivers flood the delta and refill thousands of wetlands, depositing nutrients and sediment that give the delta its sprawling flat marshland character. Some areas become drier and provide a growing area for sedge grasses, alder and willow. These drier areas provide
habitat for many fur-bearing animals, including
Beaver and Muskrat, which depend on the vegetation for food and shelter.
This diversity of plant and animal life is also important to Aboriginal peoples who have occupied this area for over 7000 years. The delta provides them with hunting, fishing and trapping opportunities that they still pursue today. The Peace-Athabasca Delta is a necessary link to their culture and the health of the delta is an important part of their future.
Over the last thirty years, the delta has been drying out. The yearly flood cycles have been reduced so that important wetland areas are not refilled. This is partly the result of the way water that has been managed upstream of the delta including the construction of a dam on the Peace River. Rainfall and snow volumes also affect how much flooding will occur during the spring. Some years, when there is very little snowfall, the delta does not get the flooding and wetland recharging that it needs.
The Peace-Athabasca Delta is recognized for its importance and efforts are underway to restore these vast wetlands and to ensure that the important yearly flood even continues to occur.
For more information on this unique site, visit the
Reprinted from Stream Connections with permission of Alberta