Sept/Oct 2008

One, two, three... green light

Innovative approaches to water quantity management on Athabasca River

By B. Berzins and B. Irvine

Lake Athabasca

Climate change and unprecedented growth are placing new demands on Alberta’s watersheds. The Government of Alberta’s Water for Life Strategy calls for citizens, communities, industry and government to work together, sharing responsibility to improve conditions. The strategy’s collaborative approach has created exciting new opportunities for innovative water management approaches to meet ecological, economic and social needs. Recognizing this opportunity, a group of scientists and engineers have been working since 2003 to develop a water management project that offers a unique solution to a growing demand for water on the Athabasca River.

Fossil Water Corporation, a Calgary-based water infrastructure development company, has been leading the development of an off-stream storage reservoir that would support the balancing of flows in the Athabasca River in anticipation of future demands from oil sands mining companies. With site investigations and design well underway, the project will help the industry mitigate future impacts on the availability of water in the river.

The Athabasca – unique among Alberta’s rivers

At 1,538 kilometres, the Athabasca River is Alberta’s longest and one of the last free-flowing (undammed) rivers in North America. It stretches from the Columbia Ice Fields in the Rocky Mountain headwaters to its mouth in Lake Athabasca. Its delta joins those of the Peace and Birch rivers to form a 6,000 square kilometre complex of wetlands – one of the world’s largest freshwater deltas and one that has supported aboriginal communities for thousands of years. It is also an important staging area for migratory waterfowl, hosting up to 400,000 birds in spring and more than a million each fall. The delta is largely undisturbed by settlements and has been designated as a Ramsar wetland and a UNESCO World Heritage Site.

Athabasca River flows vary considerably with fluctuations in spring runoff, icing conditions and precipitation recharge within the watershed. A maximum daily peak discharge of 4,700 cubic metres per second was observed in 1971, whereas the lowest observed minimum daily flow was 75 cubic metres per second in 2001. Due to icing conditions, winter low flows can persist for a two to four month period.

Growing demand for water

The ongoing development of oil sands mining projects in the Athabasca region has drawn more attention than ever on issues of water demand. Annually, 3.6 per cent of the Athabasca’s mean water volume is allocated to all users. Specifically, the projected oil sands allocation is less than two per cent of annual flow, or 50 per cent of the total allocated.

Despite a relatively low rate of annual diversion, stakeholders remain concerned about instantaneous peak demands during winter lows, when flows can dip below 80 cubic metres per second. In 2008, Golder Associates estimated that licensed demand for water diversion by oil sands operations were at a peak of 18.9 cubic metres per second, with actual withdrawals likely at 85 per cent of licensed amounts, representing a maximum potential withdrawal of 16.1 cubic metres per second.

In response, and in an effort to strike a balance between ecological, economic and social requirements, Alberta Environment and the Department of Fisheries and Oceans established the Water Management Framework (2007). The framework specifies periods during which flow is managed according to potential impacts and assigns a colour code indicating the severity of the conditions as follows:

  • Green condition: During most years, the flow in the river is sufficient to meet environmental and human needs and withdrawals are allowed up to a maximum of 15 per cent of the flow in the river.
  • Yellow condition: Applied when the river is experiencing natural low flows and water withdrawals may increase stress to the aquatic ecosystem. Records indicate this condition has occurred about 14 per cent of the time. During the yellow condition, water withdrawals proceed with caution and are limited.
  • Red condition: A designation indicating that the river is experiencing natural low flows. Records show this occurred about four per cent of the time. Total water withdrawal is restricted to ensure fish habitat loss is minimal.
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