Water Quality

Water Quality

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Water Quantity

Changes in water quality have been observed in parts of the Peel sub-basin and have affected the ability of some Indigenous communities to practice traditional land uses. The Gwich’in and members of the First Nation of Na-Cho Nyäk Dun have observed warmer water temperatures than in the past, which they associate with observed declines in the health of some fish species. Observations by Indigenous communities and scientists indicate that permafrost thaw is accelerating across the glaciated terrain in the Peel sub-basin, as evidenced by a rise in observations of slumps and ‘holes’ in the earth, and erosion along the banks of streams and rivers. Permafrost thaw has led to an increase in sediment and solute loads in adjacent watercourses, leading to observations of muddy water in local waterbodies by the Gwich’in. Streams affected by such permafrost-slumping showed lower abundances of benthic invertebrates. The potential for industrial development in the sub-basin is a concern for local communities, specifically how contaminants could affect water quality and ecosystem health.

The following table summarizes the availability of information for each Water Quality indicator.

Signs and Signals

Indigenous Knowledge Information and Data

Indigenous Knowledge Availability in Public Sources1

Science Information and Data

Science Data Availability2

Water Quality

Local observations and oral histories of good water, poor water, seasonal differences, land-based consumption practices

Some observations from few locations.

Ambient surface and ground water concentrations

Some ongoing surface water monitoring programs.

Benthic Invertebrates

Not assigned to a Sign or Signal

Not assessed.

Relative abundance of aquatic macroinvertebrates

CABIN* database contains benthic data, one academic study.

Land Use Changes

Stories and oral histories of land use cover and practices

Many observations from several locations.

Map and statistics of current vs. past land cover and land use

Georeferenced data available, but limited data on change over time.

Effluent Discharge

Not assigned to a Sign or Signal

Not assessed.

Volume of effluent discharges

Evidence from literature available.

1 Qualifiers for the availability of local and Indigenous Knowledge observations in publicly available sources: Limited = 1-2 observations; Some = 3-4 observations; Many = 5 or more observations
2 Qualifiers for the availability of science data in publicly available sources: Low = Individual studies or locations; Many = Network of monitoring stations across the basin

CABIN = Canadian aquatic biomonitoring network[26].

Water Quality

A reduction in water quality and warmer water temperatures have been observed in some locations in the Peel sub-basin.

The Gwich’in have observed warmer water conditions in some waterbodies than in the past.[27] Warmer water temperatures have similarly been observed by members of the First Nation of Na-Cho Nyäk Dun, who infer that the warmer temperatures cause fish to swim deeper in some lakes and become less accessible for fishing.[28]

Contaminants in the water is a prevalent concern among the Gwich’in, who recognize that contaminants from industrial developments could flow downstream into their territory.[29] In one study, Gwich’in fishers explained they have encountered muddy waters and unknown orange residue on surface waters, which deters their interest in fishing at some locations.[30] However, it is possible that the orange residue was spruce needle rust (Chrysomyxa ledicola) and/or iron-forming bacteria, neither of which are generally considered to be a threat to water quality.[31] Increasing temporal trends in the Peel River above Fort McPherson were observed for sulphate, magnesium and calcium for the period of 1980 to 2010, which may be related to increased groundwater discharge across the watershed as a result of permafrost thaw.[32] Trend analysis on Environment and Climate Change Canada data from 2000-2018 showed similar trends in dissolved constituents (this study). For example, April sulphate concentrations in the Peel River above Fort McPherson increased by 6.8 mg/L (10%) per year during that time. There are no surface water quality guidelines for these parameters; therefore these changes are not expected to impact aquatic life.

Contaminants in the water from upstream sources was a major topic of conversation for some participants, their friends and families

Parlee and Maloney, 2017

Trend in April sulphate concentrations in Peel River above Fort McPherson (2000-20018). Data from Environment and Climate Change Canada. Significance and slope of the trend were estimated using the Mann Kendall Trend Test. The Sen Slope (change in mg/L per year) and % change per year are displayed on the chart.

Increasingly common, large permafrost slope disturbances (mega slumps) leach previously frozen sediments to adjacent streams, significantly increasing sediment and solute loads in these systems. Suspended sediment and solute concentrations in streams affected by slumps were several orders of magnitude greater than in unaffected streams. In summer, slump impacted streams displayed day-and-night fluctuations in water levels and solute and sediment flux driven entirely by ground‐ice thaw. These effects were shown at the local and overall watershed scale and resulted in significant increasing trends in solute concentrations in the Peel River.[33]

Dr. Robert Fraser. NRCan Canada Centre for Mapping and Earth Observation, in collaboration with Northwest Territories Geological Survey and Northwest Territories Centre for Geomatics

The high relief in much of the basin, relatively impermeable substrates, lack of wetlands, and the presence of permafrost means there is a limited area where water can be stored during runoff and instead runs quickly into the stream carrying sediments. Therefore, streams in the Peel sub-basin carry naturally high loads of suspended sediments and associated metals. They frequently exceed total and dissolved metals guidelines for the protection of aquatic life[34] although resident aquatic life is likely adapted to these natural conditions. Results of Community-Based Monitoring also showed higher peak turbidity, suspended sediment, metals and dissolved ion levels in the Peel River sub-basin, compared to data collected at other sites in the Northwest Territories. [35]

Benthic Invertebrates

One study observed reduced abundance of benthic macroinvertebrates in streams affected by permafrost slumping in the Peel sub-basin.

Permafrost degradation (thaw slumps) has significantly impacted the abundance of benthic invertebrates numbers in streams of the Stony Creek watershed. Monitoring results show that as the number of slumps increase, the amount of sediment in the water increases and the number of benthic invertebrates decreases. Sediment suspended in water can smother benthic invertebrates and cause their numbers to drop. [36] It is unknown if permafrost thaw has had the same impact on benthic invertebrates elsewhere in the basin.


Land Use

Declines in the quality of resources and land disturbances are leading to changes in Indigenous land use practices in the Peel sub-basin. Natural land cover has not been directly impacted by human activity, but communities and scientific data show increased land disturbance due to major permafrost thaw slumps.

Participants […] discussed seeing ‘holes,’ or thaw slumps in the landscape, especially when driving along Dempster Highway,

Parlee and Maloney, 2017
Erosion of river banks and permafrost thaw slumps are a significant concern for the Gwich’in, who have observed mass cave-ins and the formation of ‘holes’ and thaw slumps in permafrost terrain, particularly along the Dempster Highway.[37] In one study, the most prevalent observation by the Teetl’it Gwich’in of environmental change in the lower Peel watershed was the erosion and melting of permafrost, which participants attributed to climate change.[38] Similar observations were recorded in scientific studies describing increased frequency and magnitude of large permafrost slope disturbances (mega slumps) in glaciated terrain of northwestern Canada, due to the intensification of permafrost thaw from  increased

The most common environmental observation was of erosion and melting permafrost driven by recent changes in climate,

Gill, 2013
temperatures and precipitation.[29],[39] The Gwich’in have also observed that cut banks along local rivers and streams are more numerous and taller as the banks erode. There is a concern for how permafrost thaw will continue to impact traditional use sites and remote settlements. The safety of infrastructure in towns built close to rivers is in question and there are many accounts of hunter’s and trapper’s cabins falling into the rivers in recent years.[40]

The potential contamination of water, fish and other downstream effects of industrial development is concerning for Indigenous communities in the Peel sub-basin.[41] The Gwich’in have expressed concerns about the potential contamination of water and fish linked to potential upstream industrial projects and mineral and oil and gas exploration in the Peel sub-basin, and to the south, on the Mackenzie River, due to oil sands development in Alberta.[42] Gwich’in fishers have also observed murky, polluted waters in some locations and raised concerns about sediments clouding the water. In one study, these changes were found to negatively impact Gwich’in fishing sites and deter community interests in fishing.[43],[44] Similarly, several members of the First Nation Na-Cho Nyäk Dun First Nation recall catching poor quality fish in recent years, which they chose not to consume due to contamination concerns.[45]

Some participants mentioned concerns that contaminants from the south may flow downstream in the rivers from the oilsands or other industrial areas,

Parlee and Maloney, 2017

Shrubland comprises 27% of current land cover in the Peel sub-basin. Forest covers 24% of the basin while 22% of the land cover is barren. There is currently no measurable degree of human impact on land cover.

Land Cover

Percent Land Cover

















Land Cover for Peel sub-basin


Effluent Discharges

Water quality is currently not impacted by effluent discharges in the Peel sub-basin.

Trace amounts of manmade chemicals can be found in surface water due to atmospheric transport and deposition.[46]

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