Water Quantity

Water Quantity

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Summary

Water quantity in the Peel sub-basin has undergone moderate change. Observations by Indigenous communities and scientists suggest the sub-basin is subject to significant reductions in snow and ice cover, earlier ice break-up and later freeze-up, and more variability in water levels in lakes, rivers, and creeks although levels are generally lower than in the past. These changes are largely the result of the effects of climate change over the past few decades, such as rising air temperatures and more precipitation events. Human water use within the sub-basin has no significant consequences on water quantity due to the small population. Annual average river flows have mostly been stable, but winter and spring river flows have increased by up to 2% per year. Changes in water quantity threaten to further disrupt the aquatic ecosystem health and the ability for Indigenous communities to practice traditional land uses in the sub-basin.

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

Signs and Signals

Indigenous Knowledge Information and Data

Availability of Indigenous Knowledge Observations1

Science Information and Data

Science Data Availability2

Snow and Ice

Local observations and oral histories of changes in snow quality, ice thickness, presence and break up of ice jams

Limited observations from few locations.

Available modeling information / stats on snow quality, ice thickness, presence and break up of ice jams

Snow data and analyses available and presented. Snow Bulletins available. Low availability of ice data; limited ice monitoring.

Water Flows and Levels

Local observations and oral histories of changing flow / water levels in rivers / lakes and aquifers over time

Some observations from few locations.

Seasonal statistics including changes in flow / water levels in rivers / lakes and aquifers over time

Long-term data sets available from some Water Survey of Canada stations; analyzed two representative sites on the Peel River.

Climate

Local observations and oral histories of temperature, precipitation normals and extremes over time

Many observations from few locations.

Temperature, precipitation normals and extremes over time

Data available from weather stations within the sub-basin, analyses completed.

Water Use

Not assigned to a Sign or Signal

Not assessed.

Number of water licenses, purpose, volume allocated, and volume used vs. water flow / level; Water demand from various sectors, including dams, agriculture, oil and gas, etc., trends in water use over time

Evidence from literature available.

1Qualifiers 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; Few = 1-3 locations; Several = 4 or more locations
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

Snow & Ice

Reduced duration of ice and snow cover and early ice break up and snowmelt have been observed in some locations in the Peel sub-basin.

Ice conditions are more variable than in the past, and some Indigenous communities have observed stark changes in the timing of freeze-up and break-up in rivers and lakes.[1]  Members of the Nacho Nyak Dun First Nation have observed more variability in ice conditions, reporting that the timing of freeze-up of the local lake occurs approximately 3 weeks later in recent years than in the past.[2] The shorter duration of ice cover also constricts the window of availability for ice fishing. In one study, the Gwich’in reported that the timing of freeze-up is delayed by approximately two months and now occurs in November rather than September and ice break-up on lakes now occurs about a month earlier, as the ice melts by late May in recent years.[3] Some members of Nacho Nyak Dun First Nation have witnessed how an upstream hydropower facility on the Mayo River is altering the timing of ice jams, and as a result “the river does not freeze the same.”[4]
The extent and duration of snow cover has decreased across the Arctic from 1967 to 2018. Overall, both winter and early-spring snow depths have decreased significantly in northern Yukon[5]. Average snow mass in the month of March has decreased in the southern half of the Peel sub-basin but has increased in the northern areas close to the Arctic Ocean, from 1980 to 2017[6]. Additionally, snowmelt has started earlier in recent decades, particularly in smaller Yukon mountain streams.[6]

Change in Average March Snow Mass (as Snow Water Equivalent, in mm/decade) in the Peel sub-basin 1980 to 2015. Positive (yellow, light green) values indicate increases in snow mass, negative (dark green) values indicate declines in snow mass.

Information on local observations of changes in snow quality were not found.

Water Flows & Levels

Changes in seasonal flow patterns and lower water levels in some rivers and lakes have been observed in the Peel sub-basin.

Some Indigenous communities have observed more variability in seasonal water levels in the Peel sub-basin than in the past. For instance, the Gwich’in have raised concerns about lower water levels in rivers and creeks, with some suggesting that water levels have decreased over the last 30 years.[7]

Peel River along the Dempster Highway. Image source: NOAA Photo Library via Flickr Creative Commons (copyright-free).

[M]ore sand bars have been forming in the Peel River,

Gill, 2013
 
An increase in the number of sand bars and shallower water conditions makes it challenging or impossible for people to access some areas by boat.[8] The Teetl’it Gwich’in have observed more sand bars forming in the Peel River than in the past, which some attribute to the lower currents that allow sand bars to build-up.[9] One study with four Gwich’in communities found that changes in river morphology (such as increased sand bars) and lower water levels are among the most frequently described environmental changes that limit access to fish.[10]

Changes to river morphology (e.g., increased sand bars) and lower water levels were two of the most frequently described environmental changes that created barriers to accessing fish,

Proverbs et al., 2020
 

Both Water Survey Canada (WSC) stations on the Peel River were analyzed for changes in monthly flows from the 1960s to 2017. Peel River above Fort MacPherson streamflow consistently increased from January to March by approximately 1.2% per year, and by 1.6% annually at the Peel River at Canyon Creek station. Winter flows (January to March), on average, have nearly doubled since the 1970s. These findings are consistent with previous studies, particularly in the continuous permafrost zone, and were attributed to increased surface-groundwater interaction due to permafrost degradation and increased active layer depth[6],[11].

Trends in February streamflows at Selected Water Survey of Canada Stations in the Peel sub-basin. Data labels are the Sen’s slope (annual change in mean monthly flow in m3/s) and annual percent change relative to long term mean monthly flow. Data from the Water Survey of Canada

The spring snowmelt-driven freshet has been occurring earlier at both WSC stations on the Peel River. Freshet has occurred, on average, 7 days earlier between the periods 1969-1988, and 1998-2017 at the Peel River above Fort MacPherson station. A similar trend has occurred on the upper Peel, with freshet occurring, on average, 8 days earlier. The magnitude of the freshet between these two periods (1969-1988 and 1998-2017) is not statistically different, although it visually appears to have decreased. The Peel River has experienced earlier freshet, significantly lower early summer (June) stream flows, but the late summer stream flows have not changed.

Mean Daily Discharge at Peel River Above Fort Mcpherson from 1969-1998 and 1998-2017.

 

The mean annual discharge in the mid-reaches of the Peel River (WSC station: Peel River above Canyon Creek) has increased by 1.4 m3/s annually (0.7% annual increase) from 1969 to 2017, while annual discharge in the lower reaches near Fort McPherson, has not changed. Therefore, the changes in seasonal distribution of flows have not resulted in widespread changes in annual flows.
June flows decreased by 1.4% annually at Peel River above Canyon Creek WSC station and decreased 1.6% annually at Peel River above Fort MacPherson WSC station. These patterns have been observed in other Yukon drainage basins as well and may be due to earlier spring snowmelt and runoff, which leaves less water to be discharged in summer.[6] 

Climate

Warmer air temperatures and increases in precipitation have been recorded in the Peel sub-basin. Climate data show that the largest changes have occurred in winter compared to other seasons.

Warmer air temperatures have been consistently observed by the Gwich’in in recent years, leading to longer summers and shorter, milder winters.[12],[13],[14] This observation is consistent with increasing trends in annual temperature of 3.3°C in the Peel sub-basin, which was the greatest among the Mackenzie sub-basins and across Canada.[15] Over the last several decades, winter and summer temperatures have increased in all regions and the climate projections indicate continued warming.[16] Some Gwich’in elders recall that winter temperatures could drop to 60 or 70 degrees below zero in the past, whereas today’s temperatures are much warmer. [17] Teetl’it Gwich’in elders similarly recount that the average and minimum temperatures reached in winter were much colder in their youth.[18] Climate data analyses that show that the most significant temperature increase was measured in winter, with smaller increases in the summer and fall.[19] The fact that cold regions and the cold season warm fastest is explained by the “Arctic amplification”. It is driven, amongst others, by the retreat of seasonal snow and ice that exposes darker surfaces and land cover underneath, introducing an additional warming effect across the region.[20]

Many [participants] spoke about the coldest air temperatures they have ever experienced, and how today’s winter temperatures do not compare to those of the past,

Parlee et al., 2020
 

Temperature trends in the Peel Sub-basin (1948 – 2016). From: Bonsal et al. 2020[19]

Sub-basin

Season

Temp Change (°C)

Peel

Spring

3.2

Summer

1.7

Fall

1.7

Winter

6.5

Annual

3.3

The Teetl’it Gwich’in have witnessed more extreme weather events in recent years than in the past, including blizzards, windstorms, and heatwaves accompanied by high rainfall events in the summer and fall months.[21] In one study, Teetl’it Gwich’in elders attributed the unusually high air temperatures and rainfall events to climate change and observed that heavy rains often lead to riverbank erosion and mudslide events.[22]

Winter precipitation has increased significantly, with smaller rises in spring and summer. There is an upward trend in the number of heavy snowfalls in autumn and winter with a decrease in the ratio of snow to total precipitation in the spring.[23]

Precipitation trends in the Peel Sub-basin (1948 – 2012). From: Bonsal et al. 2020[19]

Sub-basin

Season

Precip Change (%)

Peel

Spring

10.1

Summer

10.6

Fall

11.6

Winter

28.5

Annual

16.5

Note:       Spring: Mar-Apr-May          Summer: Jun-Jul-Aug          Fall: Sep-Oct-Nov          Winter: Dec-Jan-Feb

Water Use

The Peel sub-basin has a small population and no industrial activity, and thus minimal water demand.

The Peel sub-basin has seasonal inhabitants that are primarily present for subsistence activities, outfitting, and tourism. There have been no industrial developments or activities in the Peel, so there are no major water demands or diversions from the Peel River.[25] The limited water use by outfitters and tourism has likely had no impact on the Peel River.

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Water Quality