Summary of Findings
This State of the Watershed report supports watershed management planning in the Mighty Peace watershed of Alberta. This report has three objectives:
- Synthesize existing information for indicators in six indicator categories (landscape, biological community, surface water quantity, surface water quality, groundwater quantity, groundwater quality), thereby providing a snapshot that illustrates the current condition of the watershed;
- Identify information gaps for future considerations; and
- Provide background information and appropriate communication methods to engage the public and stakeholders in watershed management planning.
The main results of this report can be summarized as follows:
The Peace River and Slave River mainstems, as well as the larger tributaries (Smoky, Wabasca) are relatively healthy. They have good water quality and strong fish populations.
The Peace River brings more water into Alberta than all of the southern rivers combined. Less than 1% of the natural flow of the Peace is allocated for use because the river is large and the population relatively small (approximately 165,000 or 4% of the provincial total).
The Grimshaw Gravels Aquifer, the most important freshwater aquifer in the watershed, continues to provide a reliable supply of very good quality water. Because of its regional importance, this aquifer and its source areas must be protected to maintain integrity. At least four communities and numerous private users rely on this supply.
Riparian areas associated with streams of all sizes are largely untouched in the Wabasca, Lower Peace, Slave River, and to a lesser extent, the Central Peace sub-watersheds, indicating good health.
Riparian areas are critically important as areas of high biodiversity and buffers between human use and aquatic ecosystems. Riparian areas associated with streams of all sizes are highly disturbed in the Smoky/Wapiti (greater than 25% of all riparian areas) and Upper Peace (greater than 45% of all riparian areas) sub-watersheds.
Smaller tributaries (tertiary tributaries and smaller) in areas with high intensity of human footprint (greater than 50% of township area) are in poor health. In many cases, fish populations are under stress and certain species are extirpated and lake and stream water quality are poor. These vulnerable areas were highlighted in the report for follow-up.
As with many areas of the province, fish population densities in most monitored lakes, particularly for those with easy access, are low due to fishing pressure stress and loss/alteration of habitat.
Of the dozen aquifers that are monitored on an ongoing basis, some show signs of over-use. That is, use is higher than supply, causing declined supply that has not recovered completely. The extent of this phenomenon should be investigated for the entire watershed.
Point sources of pollution from the Aquatera and Weyerhaeuser wastewater streams and non-point sources of pollution from the City of Grande Prairie (e.g., from Bear Creek), in combination, have caused a slight reduction in water quality (from "Excellent" to "Good" on the Alberta River Water Quality Rating Index). Impacts from point sources of pollution have been a management priority for many years and those impacts have been kept to a minimum due to significant technological improvements over time. Non-point sources of pollution require attention in the future.
Certain areas that are highly valued by the stakeholders of the watershed are currently under threat. Monitoring of water quality and fish in these areas has indicated impairment. Overlap between these areas and high human footprint intensity is identified in the report and should be targeted for monitoring.
Invasive plant species in riparian areas are surprisingly high — up to 30% of coverage in some areas.
Water quantity in a major tributary of the watershed, the Wabasca River, appears to have substantially decreased. This is consistent with a climate response seen throughout the province in the late 1990s, but requires further investigation.
Groundwater quality varies greatly depending on the source aquifer and drilling location. Arsenic concentrations in freshwater aquifers continue to be a concern for drinking water quality.