Water Quantity

Water Quantity

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Summary

Water quantity in the Athabasca sub-basin has undergone moderate change. Observations by Indigenous communities and scientists suggest much of the sub-basin is subject to changes in ice quality and timing of ice break-up and freeze-up dates in many waterbodies (earlier break-up and later freeze-up). Water levels in lakes, rivers, and creeks are more variable, with lower levels than in the past and decreasing trends in Athabasca River flows, while flows in tributaries did not change. These changes may be linked to changes in climate in the past several decades, such as rising air temperatures, more precipitation events and decreased snow mass in the Athabasca headwaters. Although water use in the Athabasca River has stabilized since the year 2000, many Indigenous communities remain concerned for the impacts of water withdrawals on river navigability during low flow periods. These observed changes in water quantity have the potential to impact aquatic ecosystem health and the ability for Indigenous communities to practice a traditional way of life in the sub-basin.

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

Indigenous Knowledge Information and Data

Indigenous Knowledge Availability 1

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. Limited availability of ice data; Water Survey of Canada stations may have approximate annual ice-on/off dates; limited ice monitoring.

Water Flows and Levels

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

Many observations from several 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 stations on the Athabasca River and four stations in major tributaries.

Climate

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

No information found.

Temperature, precipitation normals and extremes over time

Data available from weather stations the basin, analyses completed.

Water Use

Not assigned to a Sign or Signal.

Not assessed.

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

Water Licenses available but not retrieved for this report. Reports 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

Changes in ice quality, freeze-up and break-up of ice jams have been observed in the lower Athabasca sub-basin. Snow mass has decreased in the Athabasca headwaters and increased in the lower Athabasca since 1981. Snow quality is impaired near Lower Athabasca oil sands mines.

Indigenous communities have observed some changes in ice quality and break-ups in the lower Athabasca. Elders from Fort Chipewyan have observed the colour of ice has changed, explaining that it no longer appears blue in the winter. They have also observed that ice is more slushy and weaker than in the past.[1] Elders and river users from Mikisew Cree First Nation and Athabasca Chipewyan First Nation have observed that ice conditions and break-ups in the Peace-Athabasca Delta are changing, reporting in one study that ice “just melts away” and that jams and break-ups no longer occur with the same force and intensity as in the past due to lower water levels and changing flood patterns in the Delta.[2] There has been much scientific documentation and research into changes in ice jam flooding on the Peace River, and key factors in the decline of ice-jam floods are changes in river flow patterns due to upstream river regulation and climate change, as summarized in the Peace sub-basin.[3] The ice-jam-induced flooding of the Delta is an important component of the ecological functionality; it replenishes wetlands, aquifers, and sustains wildlife. The reduction of ice-jam floods has been seen as a major factor in “drying of the delta” and related changes (see water levels and flow and habitat and species sections).

Ice break-up dates on Lake Athabasca occurred up to two weeks earlier during the period of 1961 to 1990; however, this trend was not statistically significant, and no recent data have been analyzed. Lake Athabasca also experienced a significantly later (on average 29 days) freeze-up date over the same period.[4] There is evidence that these break up and freeze up changes have greater impacts on lakes than rivers, and these changes may be related to large-scale climate patterns of Pacific origins (e.g., El Nino Southern Oscillation, Pacific Decadal Oscillation). While the effects of global warming on the teleconnection patterns examined in that study remain uncertain, models suggest that as climate warms, El Nino-type patterns may become more frequent and would likely result in shorter ice durations, particularly in western Canada.[5]

 

Western shores of Lake Athabasca near the community of Fort Chipewyan. Photo by Thomas Dyck.

Large increases of snow mass were observed in the Athabasca headwaters and the largest decreases in snow mass were recorded in the lower Athabasca. The latter correlate well with declining trends in winter precipitation and increasing winter temperatures presented below.

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

 

Snow mass trends were derived using a multi-dataset approach described in Mudryk et al. 2020, and provided by Environment and Climate Change Canada.

In the 2008 snowpack, many metal and polycyclic aromatic compounds concentrations were greater near oil sands developments than at more remote sites. Bitumen upgraders and local oil sands development were identified as the sources of airborne emissions that deposited on snow. Canada’s or Alberta’s guidelines for the protection of aquatic life were exceeded for seven priority pollutants; e.g., cadmium, copper, lead, mercury, nickel, silver, and zinc, in melted snow and/or water collected near or downstream of development.[6],[7] Information on local observations of changes in snow quality was not found.

Water Flows & Levels

Declining water levels in many rivers and lakes, particularly a decreasing trend in Athabasca River flows, are observed in the Athabasca sub-basin. These changes have resulted in significant impacts to river access and navigability for Indigenous communities. There is limited scientific evidence of how these changes impact aquatic ecosystem health.

Elders and river users have observed more variable water levels in rivers and tributaries in the lower and middle Athabasca than in the past.[8] Although rivers in the Athabasca sub-basin are known to fluctuate between years of high and low water, reports from Indigenous communities suggest an overall trend for the rivers to be lower than in the past which makes it more difficult to access and travel to many traditional land use areas by boat, particularly along the Athabasca River.[9]  A 2010 study documented how shallow water conditions in the lower Athabasca have created challenges for elders and river users from Mikisew Cree First Nation and Athabasca Chipewyan First Nation in navigating the main stem of the Athabasca River between Fort Chipewyan and Fort McMurray as well as smaller creeks and tributaries.[10] Observations of lower water levels in the Athabasca River were typically linked by participants in the study to an increase in industry water withdrawals in recent years. Of note, the study identified that the impacts of industrial water withdrawals on the ability for participating communities to practice their rights (such as hunting and fishing) are lessened when the flows in the Athabasca River are high, but the impacts “may be extreme” at low flow levels.[11]

Land users are finding it increasingly difficult to navigate the Athabasca River, as its levels continue to fall,

Parlee, 2011
 

Observations by elders and river users of lower water levels correlate with scientific findings, as the results of flow trend analysis show decreasing flows in the Athabasca River below Fort McMurray (this study). Mean annual streamflow at this location has decreased by 0.5 % annually from 1957 to 2018, corresponding to a 3.1 m3/s annual decrease. Monthly decreasing trends ranging from 0.2 to 0.6% annual reduction were significant for the months of September to February in Athabasca River below Fort McMurray, and also in late summer further upstream, at Athabasca, AB. No significant trends in flows were found in any of the analyzed tributaries, e.g., Clearwater River, McLeod River, Pembina River or Wolf Creek nor in spring freshet flows at any stations over the period of hydrometric record (mid-1950s to 2018, this study).

There are high flow levels on the Athabasca River at which industrial withdrawal of water may not result in adverse effects on the ability of ACFN and MCFN members to practice rights, but that at low flow levels, the adverse effects may be extreme,

Hydrograph of Athabasca River below Fort McMurray 1957-1976 and 1999-2018 (WSC data, this study)

 

Trends in September Monthly Flows at selected Water Survey of Canada Stations in the Athabasca sub-basin (this study). Note: Significance and slope of the trend were estimated using the Mann Kendall Trend Test.

 

Trends in declining water levels in lakes within the lower and middle Athabasca basin are observed by First Nations and Métis communities,[12] stewardship groups,[13] and recreational users[14], including Baptiste and Island Lakes, Skeleton Lake, and Lac La Noone. Trends analysis of Water Survey of Canada records of lake levels in Lake Athabasca showed decreasing trends in summer (this study). Lake level trend analysis of Nakamun Lake, located in the Lac La Nonne watershed, showed a rate of decline of 0.038 m in lake level between 1983 and 2008, while the declining trend in Baptiste Lake for this time period was not statistically significant.[15] Other lakes have seen increasing trends, however, with apparent increases in Winagami Lake, and statistically significant increases in Lac La Biche (this study). Declining water levels in the Peace Athabasca Delta are discussed in the wetlands section.

Trend in Lake Level in Nakamun Lake 1983-2008, Reproduced with permission from Casey (2011)[15]


Trend in July lake levels for select lakes in the Athabasca subbasin. Data labels are the Sen’s slope (annual change in mean monthly level in m) and annual percent change relative to long term mean monthly level. Data from the Water Survey of Canada

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

An increase in navigational hazards such as sand bars, dangerous rocks, and log jams along with lower water levels makes it challenging or impossible for people to navigate some areas of the Athabasca sub-basin by boat. Many Indigenous communities in the lower Athabasca have reported encounters with more navigational hazards.[16] For instance,

Most participants considered particular incidents involving hitting sand bars to be ‘too many’ to map,

Candler et al., 2010
a study with elders and river users from Mikisew Cree First Nation and Athabasca Chipewyan First Nation documented ten areas along the Athabasca River between Fort Chipewyan and Fort McMurray with a high incidence of hitting sand bars, although participants explained how in reality there are “too many [incidents] to map.”[17]

In a study with the Lesser Slave Lake Cree, an increase in flooding around Lesser Slave Lake in recent decades was the main theme in observations shared about water quantity. Increased flooding was attributed by participating community members to the removal of trees by forestry and oil and gas activities and the increased risk of flash floods in clear cut areas.[18] A 2004 report by Alberta Environment attributed flooding around Lesser Slave Lake to increased sediment transport in the East and West Prairie and South Heart Rivers, which led to sediment deposits in downstream deltas, raised the river bed and

The predominant theme in observations and concerns on water quantity was flooding,

Parlee, Geertsema and Willier, 2012
consequently increased flood hazard in this area. Channel erosion and sediment transport increased dramatically as a result of extensive channelization that began in the early 1950s and culminated in 1974. Forestry, agriculture and road construction in the Lesser Slave Lake watershed were also noted as potential contributing factors.[19]

Climate

Warmer air temperatures, increased precipitation and less winter snowfall have been observed in the Athabasca sub-basin since the mid-20th century. Climate data shows the greatest changes have occurred in winter compared to other seasons. Moisture availability shows substantial variation since the early 1900s, with slight long-term decreasing trends.

The greatest temperature increase (4.1°C) occurred in the winter, with the smallest increase of 1.3°C in the fall.[20] 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.[21]

 

Temperature trends in the Athabasca Sub-basin (1948 – 2016). From: Bonsal et al. 2020[20]

Season

Temperature Change (°C)

Athabasca

Spring

1.8

Summer

1.7

Fall

1.3

Winter

4.1

Annual

2.2

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

Annual precipitation in the Athabasca sub-basin has modestly increased (6.9%) overall from 1948 to 2012 as spring and summer precipitation increases were largely outweighed by winter decreases. The greatest increase in precipitation occurred in the spring and summer, while winter precipitation decreased significantly.[22] Variations in precipitation have been hypothesized to be related to the Pacific Decadal Oscillation, a large-scale climate cycle driven by Pacific Ocean temperatures.[23] Analyses of temperature and precipitation together indicated that there were major variations in moisture availability expressed as SPEI (Standardized Precipitation Evaporation Index), throughout the past 100+ years. In general, all regions were associated with wetter/cooler conditions from 1900 to 1915 and 1950 to 1980. Drier, warmer periods occurred from the mid-1910s through approximately 1950 and from the late 1990s until the end of the record in this study, 2011, particularly over the middle reach. These recent negative SPEI values have contributed to decreasing trends in river flows in the Athabasca sub-basin as discussed above[24] and possibly in other sub-basins as well.

Average water year Standard Precipitation Evaporation Index for the period 1900-2011 over a) the entire Athabasca sub-basin, b) lower reach of the Athabasca sub-basin, c) middle reach of the Athabasca sub-basin, and d) upper reach of the Athabasca sub-basin. Negative values indicate warmer, drier conditions and vice versa. Linear trends over the entire period and 1950-2011 are provided.

Season

Precipitation Change (%)

Athabasca

Spring

18.3

Summer

8.7

Fall

1.1

Winter

-9

Annual

6.9

Indigenous communities in other parts of the Mackenzie Basin have observed warmer air temperatures and more frequent precipitation events linked to climate change,[26] but there was no publicly available Indigenous Knowledge on temperature and precipitation for the Athabasca sub-basin.

Water Use

Water use has increased over the last century due to increased population, industrial, agricultural and mining development, but has almost stabilized since about 2000.

Water use in the Alberta portion of the Athabasca sub-basin has increased over time, with increasing demand from a growing population, agricultural activity, industrial development (particularly forestry), and water management[27]. Similarly, a population increase of 8.9% was reported from 1995 to 2010[28] in the Saskatchewan portion of the Athabasca sub-basin, indicating a similar increase in municipal demand across the sub-basin, although the population proportion of the sub-basin is minor. Largest water use increases in most sectors were recorded during the 1970s and 1980s, except the oil sands sector, where the largest increases occurred in the 1990s but where economic climate has resulted in large recent variations in production. During the early 2000s, water use had mostly stabilized.[29]

 

Historical Trends in Water Use in the AB portion of the Athabasca sub-basin for the municipal (A), forestry (B), and oil sands mining sectors (C) and water management (D).[27]


Less than five percent of the average annual flow in the Athabasca River is currently allocated for surface water use by the petroleum industry, municipalities, forestry, and others.[30] Of the five percent, less than one percent of the Athabasca River flow is used as many users do not use their full allocation, and return water to the river. As of 2018, the allocation to oil sands mining operations for water from the Athabasca River was under two and a half percent of the river’s average annual flow, while actual water withdrawn by oil sands mines in 2017 was less than one percent of the average annual flow[31]). This usage has not pushed the lower Athabasca streamflows below the allowable flow thresholds defined by the surface water quantity management framework developed for the Lower Athabasca River by the Government of Alberta.[32]

Although the volume of industrial water withdrawals represents a small percentage of flows in the Athabasca River and science-based evidence of the impacts on river flows has not been documented, Indigenous communities in the lower and middle Athabasca have observed a significant reduction in water levels that affects their ability to practice their Aboriginal rights (as described in Water Flows and Levels section of the Water Quantity indicator).

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