MIGHTY PEACE DRAFT STATE OF THE WATERSHED THE MIGHTY PEACE WATERSHED ALLIANCE STATE OF THE WATERSHED A DRAFT FOR CONSULTATION WITH REGIONAL STAKEHOLDERS Prepared by: CPP Environmental D R A F T MIGHTY PEACE STATE OF THE WATERSHED - 2 0 1 4 i D R A F T MIGHTY PEACE STATE OF THE WATERSHED - 2 0 1 4 Executive Summary The Peace River, or Mighty Peace, is the largest river in Alberta. It meanders nearly 2,000 kilometres from its source in the Rocky Mountains of BC until it joins the Slave River in northeastern Alberta. At some points approaching two kilometres wide, the river drains nearly a third of the water flowing through Alberta. Eventually, it flows through the longest river in Canada, the Mackenzie, and into the Arctic Ocean. Like all rivers, the Peace is a finite resource. The global supply of water, whether in the form of water vapour, ice, snow and rain, is constant. But expanding populations and economies mean the need for freshwater only grows. These trends necessitate cooperative and effective water stewardship. The Mighty Peace Watershed Alliance (MPWA) is a multi-sector, not-for-profit society charged with planning for the ecological health and economic sustainability of Alberta’s portions of the Peace and Slave River watersheds. It reports on the state of the watershed, promotes beneficial management practices, and develops educational programs. The MPWA commissioned three technical reports and a directory on the water quantity and quality and aquatic ecosystems of the Peace River Watershed. Based on that research and consultations with stakeholders, the Alliance chose indicators of the health of the watershed divided into six categories: Landscape, Biological Community, Surface Water Quantity, Surface Water Quality, Groundwater Quantity, and Groundwater Quality. Landscapes Land Use Human influence on watersheds can be measured using a land-cover product developed by the Alberta Biodiversity Monitoring Institute called the Human Footprint (HFP). The HFP combines data on several variables to describe the extent of the impact. By updating the index over time, researchers can identify trends, which can then feed management plans and practices. According to the Human Footprint from 2010, the Peace and Slave watersheds are largely undisturbed. Only 15.1% of the entire watershed (31,534 km2) is represented by the Human Footprint, most of which occurs in the Upper Peace and Smoky/Wapiti watersheds. Agriculture is the leading contributor to the Human Footprint. It plays a critical role in the watershed’s economy and is expected to expand with growing populations. Other activities include forestry, mining, and oil and gas extraction. Development and recreational activities also play a role. Land Cover Wetlands and riparian areas are critically important for water filtration and purification, erosion mitigation, biodiversity and wildlife. In the Peace and Slave Watershed, the health and change in cover of wetlands and riparian areas provide a good measure of watershed integrity. ii D R A F T MIGHTY PEACE STATE OF THE WATERSHED - 2 0 1 4 Wetlands cover slightly more than 29% (52,898 km) of the watershed (not including national parks, for which information was unavailable). The health of riparian areas is largely determined by human disturbance. To estimate riparian health for the entire watershed, computer mapping was used, along with a combination of data sets selected for their compatibility. Based on this assessment, the land cover in riparian areas associated with streams varied, ranging from 53% to 100% within the sub-watersheds. Areas with the greatest natural cover – such as the Slave River – were found to have low levels of disturbance and high forest cover. In the Smoky/Wapiti and Upper Peace watersheds, where both agriculture and development are widespread, the riparian areas have much less natural cover. Biological Community Wildlife can reveal much about the health of a watershed. While a complete inventory of the Peace/Slave watershed is unfeasible, fish act as a useful indicator of aquatic ecosystem health. Fish populations are valuable to people, sensitive to disturbance, and often have a recorded history. Fish can be affected by the addition of harmful substances to the water, and by the habitat fragmentation that results from removing vegetation along waterways or constructing stream-crossings and water-control structures. The Peace and Slave watershed has a variety of native fishes. The presence or absence of sensitive species serves as an indicator of the quality of overall fish habitat. Comparing the density of sensitive fish species between sub-watersheds can help managers prioritize conservation activities. The densities of two species sensitive to human activities, arctic grayling and walleye, suggest fish populations in the Peace River are relatively healthy. They are also healthy in the larger mainstem tributaries, such as the Smoky, Little Smoky, and Wabasca rivers. These populations benefit from a cool to cold-water water habitat. Densities in smaller tributaries – where fish are strongly affected by land use – are moderate to low. Abundant populations are found only in the Rocky Mountains and the foothills in the southern part of the watershed (typically in areas designated as Protected), and the remote areas of the northern part of the watershed, such as in Wood Buffalo National Park. Fish populations in some lakes are under stress from fishing pressure, loss or alteration of habitat, and lack of oxygen resulting from nutrient loading. Fish population status in lakes is typically correlated with proximity to urban development (representing fishing pressure) and surrounding land use. Surface Water Surface Water Quantity Each year, about 48.6 billion m3 of water flows into Alberta via the Peace River, or roughly three times the combined amount of all the rivers in southern Alberta. Much of this water originates in the mountains and foothills where tributaries like the Smoky and Wapiti rivers begin. The sidebar map shows high water-yield areas for the Peace/Slave watershed (those with the top 25% yields per square kilometre in the entire Peace River watershed). These areas generally have a surplus of water, which benefits downstream rivers and lakes. Less than 1% of the iii D R A F T MIGHTY PEACE STATE OF THE WATERSHED - 2 0 1 4 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 Peace River flows at Dunvegan (above the confluence with the Smoky River) show a change following dam commissioning in 1968. Otherwise, there is no long-term change in Peace River flows. Surface Water Quality In the Peace/Slave watershed, the source and the quantity of flow are the biggest factors influencing surface water quality. When flow volumes change, as they typically do with the seasons, the water quality also usually changes. Large volumes of water have a greater capacity to move soil particles that have chemicals bound to them, such as nutrients and metals. By contrast, low flow conditions have a reduced dilution capacity, accentuating point sources of pollution. This is particularly evident in the Wapiti River as it flows past Grande Prairie. The Alberta River Water Quality Index (ARWQI) combines multiple measurements of the metals, nutrients, bacteria and pesticides that influence water quality. Measurements used in the RWQI all come from sites forming part of the Long-Term River Network (LTRN). Within the Peace/Slave watershed, there are five LTRN monitoring sites. Over the years from 1996 to 2010, all of these sites had good to excellent scores. But this index is a broad overview of water quality in major rivers; it does not represent conditions in smaller tributaries, which are typically much worse in areas with high human footprint. Groundwater Groundwater Quantity Groundwater cannot be described by sub-watershed boundaries, since it does not respect topographically defined watershed boundaries. Rather, in the Peace River Watershed, groundwater is placed in western and eastern groupings of sub-watersheds. In general, the western grouping has a shortage of high-yield freshwater aquifers. Highyield aquifers are typically associated with permeable sand and gravel deposits in the surficial geology, which allows groundwater to flow at significant rates. Groundwater resources in the eastern grouping appear to be abundant, but mapping in this area has limited feasibility. The watershed has less groundwater monitoring information available compared to the province’s southern watersheds. But the water resource issues facing the Peace River watershed are also less urgent. Currently, the most comprehensive regional groundwater- monitoring program in place is ESRD’s Groundwater Observation Well Network (GOWN). Twelve groundwater observation wells are active within the Peace River watershed, the majority of them located near Grande Prairie and the town of Peace River. Groundwater allocations have increased 10% in the watershed between 2011 and 2013. The total allocated in 2013 was 20,940,065 m3. Groundwater use is greatest in the Wabasca and Smoky/Wapiti sub-watershed, which together account for more than 80% of groundwater allocations in the entire watershed. iv D R A F T MIGHTY PEACE STATE OF THE WATERSHED - 2 0 1 4 Groundwater Quality Little monitoring data is available on groundwater quality in the watershed. Most information exists in baseline data that describe aquifers in their natural state between the late 1960s and early 1980s. Data are unavailable on the impacts of climate change and various land uses on groundwater quality and aquifers. Municipal growth, along with agricultural, industrial and commercial activities could all have an effect. In some areas, the groundwater quality faces stress due to development pressures associated with mining. The Peace and Slave watershed could benefit from a monitoring program. There is much variability in the depth, extent and quality of surficial aquifers. They tend to have the best water quality, but are also the most vulnerable to contamination because they are near the surface and often covered by material that has high infiltration rates.