Drought in an Arid Land: When dry prairies get drier

March 30, 2026

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• Grasslands
• Groundwater
• Rivers
• Wildwater
• WLA Archive

Wildlands Advocate article by Ruiping Luo, AWA Conservation Specialist

Read the PDF version here.

 

Water shapes our lands. It erodes mountains and carves valleys, brings essential nutrients and sediments, and feeds plants and animals. We rely on it for our food, our cities, our industries, and our energy. Everywhere, water leaves a mark.

In the prairies, water shapes the land by its absence as much as by its presence. The towering Rocky Mountains to the west block moist Pacific air, and far from any other large bodies of water, most of the exposed, windswept plains are too dry for trees. The distinctive grass-dominated communities have adapted to survive in the arid environment, providing food and shelter to grassland inhabitants through the harshest droughts.

Of course, there is water here. Beneath the soil, away from the punishing wind and sun, water collects. Deep roots reach for these important drops, raising them to the surface, storing them in thirsty leaves and stems, and eventually releasing them back into the dry air. From these limited reserves, an ecosystem is sustained.

In other places, water touches the land in more obvious ways. Rivers meander through canyons, anchored in places by sparse trees. Melting snow sinks into the soil, pooling in wetlands or trickling into rivers. Heavy rain and hail contribute to rising water levels, drowning the riverbanks and leaving behind nutrient-rich sediment.

Still, for much of the prairies, water is a precious resource. A careful balance of drought, flood, and fire, along with grazing animals, has maintained this land for millennia.

Now, new activities threaten to destroy this balance.

Most of the native grasslands, tolerant of drought and flood, are gone. Many have been replaced with fields of uniformly planted crops, others torn apart in the search for oil, gas, minerals, and gravel, and still more paved over with concrete for roads and cities. All of these new uses also need water.

In total, 9.5 billion m³ of water a year are licensed for use in Alberta. Most of this occurs in the prairies, where licences allow about 7.6 billion m³ to be used annually, creating a massive strain in a region where water is already scarce.

The choice to grow certain crop varieties requires water. For many of southeastern Alberta’s uplands — places normally too dry to support crops — potatoes, sugar beet, beans, peas, canola, and alfalfa, among other choices, need water to survive the hot summers. To support these varieties, Alberta irrigates 571,737 hectares of land, more than twice all the irrigated land in the other provinces added together. About half of Alberta’s surface water, the water found in our lakes and rivers, is licensed to agricultural use, according to data from the Alberta Flow Estimation Tool for Ungauged Watersheds for 2025. Most of this water use occurs in the prairie region, where 60 percent of surface water (4.6 billion m³) is licensed for agriculture. Over 98 percent of these licences by volume, or over 4.4 billion m³ a year, are for irrigation.

After agriculture, most of Alberta’s water goes to industrial use. Water is needed in drills and fracking, to operate equipment, and to refine petroleum products (oil and gas). It is used to separate valuable minerals and precious metals from mined ore, clean materials and products, and transport crushed materials. Around 31 percent of Alberta’s surface water is licensed to industry. More of this use occurs further north, though industrial licences still cover about 19 percent of licensed water in the prairies, or 1.4 billion m³. Unlike agriculture, most of this licensed water is considered non-consumptive use and remains in the environment… However, this water may carry pollutants or be at a higher-than-normal temperature, and if returned to rivers or lakes can further degrade the health of our watersheds.

The prairies are also home to most of Alberta’s population. They contain the two largest cities, Edmonton and Calgary, as well as many of the province’s smaller cities and towns. Of the over 5 million people who make their home in Alberta, just under 4.5 million are reported to live in the prairies, according to census population data for July 2025. These cities and towns need water for drinking, washing, gardening, and sewage, as well as in emergencies such as fires. Roughly 13 percent of water is licensed for municipal use across Alberta, and 14 percent in the prairies.

The remaining 6 percent of surface water licensed in Alberta and in the prairies is classified as commercial (for construction, transport, manufacturing, gardening, retail, and recreation) or water management. Of this, only about 0.9 percent is explicitly marked for conservation reasons, such as habitat improvements or wildlife management.

The three major river basins that cross the prairie regions are the South Saskatchewan, North Saskatchewan, and Milk River Basins. According to the 2010 Facts about water in Alberta released by the provincial government, the combined mean annual discharge of these three river basins is an estimated 16.6 billion m³. This suggests that nearly half of these river basins have been allocated for use in Alberta’s prairies alone.

That might not seem like much, but these river basins aren’t confined to Alberta. The North Saskatchewan and South Saskatchewan both cross into Saskatchewan, and the Milk River Basin is shared with Saskatchewan and the United States, where more water from these rivers will be withdrawn for use.

Further, mean annual discharge does not describe the variation between years and between months. For example, the discharge of the Bow River, measured by the Water Survey of Canada in Calgary, varied from 30 m³/s (in October 2023) to 359 m³/s (in July 2022). Average annual flows between 2021 and 2024 showed a high of 224 m³/s and a low of 118 m³/s, while average monthly flows in July and August, when water requirements are usually highest, varied from 73 m³/s to 215 m³/s. In a dry year, water allocations account for a much greater portion of our river water.

When surface water runs low, residents often turn to groundwater. Groundwater management is more complex than surface water, and provincial licences only represent a portion of the groundwater used. Still, Alberta licenses roughly 480 million m³ of groundwater across the province, most of it to industry, agriculture, and municipalities. Over 120 million m³ of groundwater is licensed in the prairies, not including some private wells used for agricultural or household purposes.

Except, groundwater is not inexhaustible either. Surface water and groundwater are inextricably linked; surface water seeping into soil recharges groundwater, and groundwater contributes to surface water where the water table is high. In times of drought, groundwater also declines, and some of southern Alberta’s groundwater levels have decreased in recent years, according to the Groundwater Observation Well Network.

This overuse is affecting prairie ecosystems. In order to maintain a strong and resilient ecosystem, our rivers, lakes and soils need enough water to support their functions, the aquatic plants and animals, and the surrounding riparian and terrestrial communities that rely on them. As water levels drop, pollutants become concentrated and more toxic, and temperatures become less stable. Less water means that rivers and lakes heat up more easily, and since oxygen dissolves better in cool water, this means less oxygen. This can trigger more algal blooms, as toxic cyanobacteria (blue-green algae) prefer warmer water. Under these conditions, fish and other organisms struggle to survive, leading to massive die-offs.

Worse, as ecosystem health degrades, rivers and lakes are less able to fulfill functions to maintain water, leading to even more water loss and degradation. For instance, aquatic and riparian vegetation helps to stabilize riverbanks, preventing erosion and supporting water percolation into soil, where it is stored as groundwater. Trees and other plants shade the water, reducing evaporation. Bacteria, fungi, plants, and filter-feeding animals help to remove toxins and excess nutrients. Without enough water to support the aquatic ecosystem, we also lose these services and the natural ability of ecosystems to clean and store water.

Acknowledging the importance of maintaining our watersheds, Alberta has established Water Conservation Objectives (WCOs) for some of southern Alberta’s rivers. However, not only are the current WCOs not enough to protect aquatic and riparian ecosystems, they are often not met anyway, risking the health of our watersheds and the surrounding prairie. The current allocation of water in southern Alberta is already too much for our watersheds to support.

Water shortages are only expected to get worse. Along with the degradation of aquatic and riparian ecosystems affecting water storage, climate change is predicted to cause more severe and prolonged droughts. Glaciers, which feed our rivers in the spring and summer, are disappearing, and average summer temperatures are rising, leading to less inflow and more evaporative loss. For the past few decades, average flows in many of our rivers have been declining, according to data from the University of Alberta and University of Lethbridge. Basically, we can expect less water to be available in the future.

Reservoirs are often proposed as a solution to future drought, but there are several problems with this. First, they do not solve the issue of having less water available. We are expecting higher temperatures, reduced snowfall, melting glaciers, more extreme rainfall, and degradation of our ecosystems, all leading to less surface water that can be diverted to reservoirs. In some cases, reservoirs can actually worsen the situation, since the higher surface area and the slowing of water can increase evaporation, causing greater water losses during the critical summer months. Larger reservoirs have even been shown to affect rainfall patterns, potentially decreasing rainfall near where dams were built.

Second, reservoirs can increase water use, as they create a false sense of security. Dams may help to protect against small droughts, but they are unable to protect against longer and more severe drought periods. Because water is still available during the initial drought stages, the warning signs are often ignored, leaving communities vulnerable to far more devastating conditions. A study in Nature Sustainability found that reservoirs can encourage communities to consume water beyond what is available in the area.

Reservoirs also need to be maintained. Dams trap sediment, filling in the reservoir and decreasing their capacity to store water. They are vulnerable to disasters, such as storms and extreme temperatures, which can lead to failures. In 2025, the American Society of Civil Engineers estimated a cost of over $165 billion USD ($224 billion CAD) to repair the United States’ aging dam infrastructure. A similar comprehensive study has not been released for Canada, but several warnings have already been raised about the country’s aging infrastructure. Globally, many dams are reported to be at risk of either drying up or collapsing.

Finally, dams and reservoirs can be highly damaging to the nearby ecosystems and contribute to climate change. When reservoirs are first built, they flood the upstream river valleys. Often, these river valleys contain some of our last remaining native prairie, an ecosystem already highly at risk, and displace the many species that rely on this land. During the first few years of a dam’s operation, vegetation and soil organisms in the newly flooded land will die and decompose, releasing methane and carbon dioxide into the atmosphere. Bacterial activity will generate further emissions for decades. In 2016, researchers reported that greenhouse gas emissions from reservoirs accounted for 1.3 percent of all human-caused emissions — more than Canada’s total emissions that year — and 6 percent of methane emissions. After a dam is established, it acts as a barrier to fish, aquatic insects, bacteria, algae, and other organisms, preventing animals and nutrients from travelling past the structure. Although structures like ladders can sometimes help fish to move past the dam, they remain as obstacles to the smaller organisms in the water. With the barrier in place, downstream water quality often degrades, especially where water levels are significantly lowered by the reservoir.

There are solutions other than reservoirs, the most obvious one being to decrease water use. Irrigation can be reduced by focusing on growing less water-intensive crops, such as lentils, chickpeas, millet, and drought-resistant varieties of wheat and barley. Taking advantage of spring rains by adjusting the time of planting can further reduce the need for water, and using mulch or cover crops can decrease soil evaporation. Where irrigation is necessary, using more efficient irrigation systems — such as drip irrigation, which delivers water directly to the roots — can reduce water losses to evaporation and wind.

Reducing the extent of industrial and municipal use is also important. For municipalities, using drought-tolerant plants for gardening means less water is needed to maintain lawns, as is providing habitats for native pollinators and other important species. Installing more efficient water systems or a greywater system, which collects wastewater from showers or sinks to reuse in flushing toilets or watering lawns, reduces personal water use. In industry, limiting the development of new mines, drill sites, and processing, especially during drought periods, and reconsidering water-intensive projects, can help our diminishing water stores to recover.

Southern Alberta’s water systems are already strained, and we are starting to see the effects of that overuse. For us to survive the next drought and protect our sensitive ecosystems, we need to change our approach to water. We need to acknowledge the scarcity and value of this resource in the arid prairies.