This year saw the hottest and driest summers in recent history for western Canada and the American Southwest. The resulting drought adversely affected the food supply and helped meat prices rise three times faster than inflation.
Despite the severity of these droughts, the worst is still to come. Extreme weather events in the Prairies are expected to be increasingly severe and frequent, with prolonged dry periods as well as the risk of flooding from intense rain storms.
While Canada benefits from a world-class agricultural technology industry, lessons can also be drawn from low-tech solutions developed by ancient societies that thrived in arid climates. One such society was the Nabataean culture, which flourished 2,000 years ago in the ultra-arid deserts of Jordan, northern Saudi Arabia, and southern Israel. For more than a decade, I have worked on the region’s Nabataean and Roman archeological sites, discovering their construction practices and innovative strategies for overcoming environmental limitations.
Masters of Hydraulic Engineering
Known for their rock-carved monumental facades in the UNESCO World Heritage Sites of Petra (their capital) and Hegra, the Nabataeans prospered from the trading sun between southern Arabia and the Mediterranean. But it was another skill that allowed him to flourish in his arid homeland.
Based on local techniques as well as techniques adopted from neighboring cultures, the Nabataeans became masters of hydraulic engineering. They built complex water management systems that included dams, catchment systems, underground pools and aqueducts. These systems were designed to maximize the amount of rainwater collected and stored during the wet winter months and to minimize the amount of water lost through evaporation during the dry summer months.
In Petra, the Nabateans built a network of dams to protect their capital from flash floods and covered channels to deliver water to the city centre. In the surrounding hills, they built terraces to absorb runoff, reduce the risk of flooding, and support agriculture. These catchment and distribution systems were so effective that the Nabataeans built open-air pools and monumental fountains in Petra as a showy display of their wealth and power.
At the archeological site of Hawara (modern Humayama), south of Petra, Canadian archaeologists have discovered and documented the settlement’s extensive water supply system. Here, catchment systems directed rainwater runoff into large pools that stored it for use in the dry season. These cisterns were roofed to prevent evaporation and were equipped with settling basins to collect sediment. The 26.5-km spring-fed aqueduct also supplied drinking water to this settlement. Most of this system is still in use today.
Ancient Techniques for a Modern Problem
Despite being developed and built over two millennia ago, efforts are underway to revive the Nabataean water management systems around Petra to help support flood control and agricultural development. Elsewhere around the world, archeology has advanced our understanding of sustainable farming and has the potential to make a meaningful contribution to contemporary water politics. While the implementation of these landmark solutions may not by itself solve the complex issues we currently face, they will likely play an important role in helping us adapt to hot and dry climates.
Although the climate and hydrology of the Canadian Prairies are very different from those of northern Arabian deserts, some similarities do exist. Just as winter rains in northern Arabia sustain life during the summer months, runoff from snow melt in the prairie plays an important role in recharging groundwater and represents a significant portion of stream flow during spring. Is.
Like underground cisterns made by the Nabataeans, the dug pits known as dugouts are an important source of water for prairie farmers. While these man-made reservoirs can be supplied by groundwater, they often rely on spring snow melt. During drought conditions last summer, however, many of these dugouts dried up, forcing many farmers to rely on pumped groundwater, which comes with its own issues.
Adopting the same sustainable practices used by the Nabataeans to maximize the amount of water collected and minimize evaporation losses can help increase the effectiveness of these reservoirs. Just as the Nabataeans placed their pools to maximize the catchment of runoff, dugouts should be strategically located in fields to melt as much snow as possible. The amount of snow melt can be further increased by the use of well-designed shelterbelts, which have rows of trees and shrubs that act as a windbreak and can also encourage snow accumulation. Huh.
Settling tanks such as those built by the Nabataeans to prevent sediment accumulation in their cisterns could be used to prevent sedimentation in dugouts, improving both storage capacity and water quality.
The Nabataeans were also careful to avoid evaporation, and may have benefited from covering modern dugouts to reduce water loss. Global studies have shown the effectiveness of physical covers at slowing the rate of evaporation, and more recently California has proposed covering its canals with solar panels to help preserve its water supply while producing green electricity. So to receive.
part of an integrated strategy
While greater investment in water storage systems will improve water security in the prairie and reduce the effects of prolonged drought, these storage systems may also have the added benefit of reducing flood risk while maintaining runoff. Is.
While the adoption of these low-tech and sustainable solutions won’t make the prairie itself drought-proof, when combined with innovative cropping techniques they can play a vital role in helping Canadian farmers mitigate the growing impacts of climate change .