Lakes in Reclaimed Landscapes

Lakes will be a significant component of the reclaimed landscape in the oil sands region. A 2007 report by Clearwater Environmental Consultants for the Cumulative Environmental Management Association (CEMA) indicates that the lakes will vary greatly in size, shape, volume and the amount of oil sands tailings that may be present.

The CEMA End Pit Lake Subgroup developed the following definition: an end pit lake (EPL) is an engineered water body, located below grade in oil sands post-mining pits. An EPL may contain oil sands by-product materials and will receive surface and groundwater from surrounding reclaimed and undisturbed landscapes. EPLs will be permanent features in the final reclaimed landscape, discharging water to the downstream environment.

CEMA has an interactive map of 29 lakes showing location and design characteristics and has summarized some of the key characteristics in a table format. Some of the highlights:

Characteristic

Total

Average

Low

High

Lake Area

115.5 km2

3.98 km2

0.4 km2

14 km2

Lake Volume

4,972 Mm3

171.45 Mm3

3 Mm3

916 Mm3

Tailings Volume

1,049 Mm3

95.4 Mm3

2 Mm3

215 Mm3

% Volume that is Tailings

45%

2%

87%

Lake Depth

25 m

6 m

90 m

To put the lake area in context of natural lakes in the area, Kearl Lake is almost 6 km2 and Gregoire Lake is almost 26 km2.

To put the lake depth in context of natural lakes in the area Kearl Lake is very shallow, with a maximum depth of just 2.5 m, while Gregoire Lake has a maximum depth of just over 7 m.

Only 11 of the 39 lakes are planned to have tailings.

The lakes will finish filling anywhere from 2015 to 2065.

Read the CEMA report for more background on end pit lakes including their physical, chemical and biological characteristics. The report also identifies knowledge gaps and future research needs.