Water Resources Research Projects

Over the last number of years, there has been a growing awareness of the need to protect and properly manage Canadian water resources, specifically under the supply/demand conditions that are suggested will exist under a warming climate (IPCC, 2001). A recent national assessment (Maxwell et al., 1997) highlighted that a complete understanding of the changes in water resources in Canada resulting from changing climate is far from complete. It is understood that the impacts across Canada will be quite varied and the implications more profound in some areas than in others. Steep climatic gradients in mountain watersheds make their hydrological and ecological regimes particularly sensitive to a changing climate. Western Canada’s mountain watersheds, many of which are glacierised, provide freshwater for domestic and industrial use. Moreover, the ecology of glacier streams are strongly affected by longitudinal temperature gradients and hydraulic conditions that vary with headwater extension (glacier retreat) and contraction (glacier advance). Proponents of the CCAF, PARC and PERD initiatives, the Canada Country Study and climate change perspectives provided by other national and international programs (e.g., IPCC), have prescribed that further work is necessary to characterize the vulnerability of streamflow in the mountains, and regions adjacent to them, to future changes in the amount of glacier cover.

In a mountain watershed, the influence of even small areas of perennial ice on the seasonal variation of runoff is marked. The duration of snowmelt runoff is extended since glacial catchments generally extend to higher elevations than those that are solely nival; the major nival/glacial contrast results from the limited life of the snow reservoir. As the seasonal snowline ascends to higher elevations, increasing areas of glacier ice and firn, having a lower albedo than snow, are exposed, increasing rates of meltwater production. Moreover, melt is augmented by the action of supra-glacial, en-glacial, and/or sub-glacial water flow, regardless of its origin as precipitation (rain) or surface melt from latent heat exchange. Often, a late spring snowfall will radically delay the timing of seasonal flow contributions, while contiguous, non-glacial areas, subject to the same snowfall but very different heat flux regimes, will respond more rapidly.

Temperate mountain glaciers manifest i) a delayed and extended period of maximum seasonal discharge and ii) a regulatory effect over streamflow such that annual and monthly variations are reduced. Glaciers act as storage reservoirs that can contribute to streamflow during periods that would otherwise be in a state of low flow. They also act as a source of disturbance during intense weather when, for example, rain-on-ice persists for several days, causing extreme flow events and dramatic geomorphic shifts. A typical annual hydrograph exhibits base flow augmentation by snowmelt runoff during a period of rising temperature in spring; followed in summer by peak flows resulting from rainfall superimposed upon glacier melt. At the daily-scale, glacial streams, near the glacier margins, exhibit a late afternoon diurnal flow peak. The water-resources in the western Canadian prairies are under increasing pressure from i) the need to provide adaptation strategies based on a reduced reliance on fossil fuel energy sources under the Kyoto Protocol ii) interests outside Alberta and Canada regarding bulk water transfers and flow fragmentation (e.g., Manitoba-North Dakota iii) evolving concerns amongst the Prairie provinces regarding inter-provincial water allocation. Moreover, current activities within Canada (Environment Canada) regarding the rationalisation of the hydrometric network have been responsive to the importance of glaciers in terms of identifying hydrological regimes which are of high scientific merit (e.g., Reference Hydrometric Basin Network or, RHBN). Glacial melt water from the eastern slopes of the Rocky Mountains is recognised as an important factor in adapting to the above pressures- the principle question being, “For how long can such sources reliably regulate streamflow under projected variations in climate?”.

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All major climate-change agenda efforts in recent years echo the need for more empirical scientific information about climate change and adaptation to freshwater ecosystem impacts. The adaptation research undertaken in this study begins the process of providing answers to the general question posed by resource managers and other stakeholders, “What options can we choose from to ensure the sustainability of the aquatic resources under our stewardship?” More specifically, the research results in a systematic methodological framework which resource managers could build on to determine adaptation options for specific lake types, as well as examples with respect to such options.

Research concentrates on the numerous larger lakes in the Boreal Plain which, although they are not necessarily “cold” lakes, tend towards the “cold” end of the temperature spectrum. The biophysical components of these lakes are highly vulnerable and, unlike some of the smallest lakes, which could simply disappear if climate change impacts were extreme, many of the biophysical elements of these lakes would probably continue to exist. The research in this study addresses resources in relation to climate change and adaptation at three levels of ecological organization. The three are lake habitat, intermediate levels in food webs, primarily smallbodied fish species, and large-bodied fish species.

This study focuses primarily on two large-bodied cold-water species, lake whitefish (Coregonus clupeaformis) and lake trout (Salvelinus namaycush), both salmonids. All analyses begin under the umbrella of climate-related total allowable catch, or TAC, probably the most direct, integrative, management tool. Yield calculations per se have been based on relatively simple empirical models, in which fishery yields are related to summer thermal habitats.

Two lakes were selected for inclusion, Lake Winnipeg and Kingsmere Lake, Prince Albert National Park, as examples of a large but relatively shallow water body and a relatively deep system respectively. Lake Winnipeg deserves special attention simply because it is one of the world’s great lakes. Kingsmere Lake provides one of the few examples of a cold, dilute system for which one can investigate process and pattern, in an integrated manner, across a range of trophic or food web levels.

This study offers resource managers the only set of empirical harvesting models for cold freshwater fish which will conserve population structure in the target populations. These models are based on climate-related habitat features. These models substantially improve the precision of previous efforts; more importantly however, they add accuracy through the incorporation of conservation considerations. Continued use of any previous empirical models will ultimately have disastrous effects on all freshwater fisheries, if they haven’t already. The new climatebased TAC models are highly predictive for most lakes, but analyses indicate the model for lake trout may be inadequate for lakes <1000 km2 in surface area. More work is needed in the development of the lake whitefish TAC for all lakes, regardless of size, since sustained yields may yet be overestimated by the model developed in this study. As a great lake, we need to know far more about all aspects of Lake Winnipeg to manage it properly, regardless of the issue or context.

It is probable that we can best adapt to climate change through proper management of our remaining fish stocks. Additional management adaptation requirements include the development of adequate fishery monitoring programs, few of which exist in the Boreal Plains Ecozone. In the short term, management agencies across the Boreal Plain Ecozone should implement a moratorium on lake trout fishing; this is the only real hope for the lake trout of the ecozone. The management agencies should also implement a comprehensive in-depth assessment of the state of surviving lake trout populations. Lake trout in the Boreal Plain are in a similar situation to that of large carnivores in the Rocky Mountains, where the fate of the “last of the last, not the last of the best” (c.f. P. Paquet) is at stake.

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Water is essential to life and socio-economic development. In the populated southern parts of the Prairie provinces, surface water bodies of significant size are limited and many are not reliable water sources due to inadequate supply and/or unsuitable water quality. In the absence of abundant surface water supplies, groundwater has historically played a very significant role as a water supply source in the Prairie provinces. However, reliance on groundwater across the provinces may vary from region to region. It is estimated that in Saskatchewan approximately 45% of the population relies on groundwater as a source of drinking water (Government of Saskatchewan, 1999). Pupp et al. (1989) indicate that about 26% of the population in Alberta uses groundwater as their water supply source. Approximately 20 % of Manitoba’s population relies on groundwater for their potable water supply source. In addition, groundwater is used for agricultural and industrial purposes in all three provinces.

Droughts in the Prairies are common and they have had a significant negative impact on the economy of the Prairies and on the population (Maybank et al., 1995; PFRA, 1998; Wheaton, 2000). Since surface water resources have virtually all been allocated, groundwater is looked upon as an additional/alternate supply source during droughts. Groundwater is a renewable resource but not unlimited due to the geological setting and climatic conditions of the Prairies. Recharge to surficial and shallow intertill aquifers is limited because of the low amounts of precipitation due to the arid climate. The low hydraulic conductivity of thick till and bedrock aquitards limits the recharge to deeper aquifers.

The present report is a compilation and preliminary evaluation of the knowledge of the groundwater resources in the prairies and identifies areas of research which could further enhance the understanding of the resources and how they can be best managed to deal with climatic changes.

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