Researchers and archaeologists are looking at how ancient civilizations managed their water in scarce areas.
The discoveries can inspire current techniques to tackle worsening droughts that have resulted from climate change.
Ancient cultures constructed complex water management systems that included dams, catchment systems, underground cisterns and aqueducts.
This year witnessed one of the hottest and driest summers in recent history for Western Canada and the American Southwest. The resulting droughts adversely affected the food supply and helped raise meat prices three times faster than inflation.
Despite the severity of these droughts, the worst may be yet to come. Extreme weather events are expected to become increasingly severe and frequent in the Prairies, with more extended dry periods coupled with the risk of floods from intense rainstorms.
While Canada benefits from world-class agricultural technology, lessons can also be drawn from low-tech solutions developed by ancient societies that flourished in arid climates. One such society was the Nabataean culture, which thrived in the hyper-arid deserts of Jordan, northern Saudi Arabia and southern Israel 2,000 years ago. I have worked on this region’s Nabataean and Roman archaeological sites for over a decade, exploring their building practices and innovative strategies for overcoming environmental limitations.
Masters of hydraulic engineering
Known for their rock-carved monumental facades at Petra’s UNESCO World Heritage sites (their capital) and Hegra, the Nabataeans grew wealthy from trading incense between southern Arabia and the Mediterranean. But it was another skill that allowed them to flourish in their arid homeland.
Drawing on local techniques and those adopted from neighbouring cultures, the Nabataeans became masters of hydraulic engineering. They constructed complex water management systems that included dams, catchment systems, underground cisterns and aqueducts. These systems were designed to maximize the amount of rainwater collected and stored during the wet winter months and minimize the amount of water lost through evaporation during the dry summer months.
At Petra, the Nabataeans constructed a network of dams to protect their capital from flash floods and covered channels to deliver water to the city centre. They built terraces to absorb runoff in the surrounding hillsides, mitigating flood risk and supporting agriculture. So effective were these catchment and delivery systems that the Nabataeans built open-air pools and monumental fountains in Petra as ostentatious displays of their wealth and power.
South of Petra, at the archaeological site of Hawara (modern Humayma), Canadian archaeologists have explored and documented the settlement’s extensive water supply system. Here, catchment systems directed rainwater runoff to large cisterns that stored it for use in the dry season. These cisterns were roofed to prevent evaporation and were furnished with settling basins to collect sediment. A 26.5-kilometre spring-fed aqueduct also supplied this settlement with drinking water, and much of this system is still in use today.
Ancient techniques for a modern problem
Despite being developed and constructed two millennia ago, efforts are underway to revitalize the Nabataean water management systems around Petra to help with flood control and support agricultural development. Elsewhere across the globe, archaeology has advanced our understanding of sustainable farming and holds the potential to contribute meaningfully to contemporary water politics. While implementation of these historical solutions may not by themselves solve the complex issues we currently face, they will likely play an essential role in helping us adapt to a warmer and dryer climate.
Although the climate and hydrology of the Canadian Prairies are very different from the deserts of northern Arabia, some similarities exist. Just as winter rains in the north of Arabia sustained life during the summer months, runoff from snowmelt in the Prairies plays a vital role in recharging groundwater. It represents a significant portion of streamflow during the spring.
Like the underground cisterns built by the Nabataeans, excavated depressions known as dugouts are an essential source of water for Prairie farmers. While these human-made reservoirs can be supplied by groundwater, they often rely on spring snowmelt. However, during the drought conditions of this past summer, many of these dugouts dried up, forcing many farmers to rely on pumped groundwater, which comes with its own set of issues.
Adopting sustainable practices similar to those used by the Nabataeans to maximize the amount of water collected and minimize the amount lost to evaporation can help increase the effectiveness of these reservoirs. Just as the Nabataeans placed their cisterns to maximize runoff catchment, dugouts should be strategically located in fields to collect as much snowmelt as possible. The amount of snowmelt captured can be further increased by using well-designed shelterbelts, which comprise rows of trees and shrubs that act as a windbreak and can also encourage snow accumulation.
Settling tanks such as the ones the Nabataeans built to prevent sediment accumulation in their cisterns could also be used to avoid sedimentation in dugouts, improving storage capacity and water quality.
The Nabataeans were also careful to avoid evaporation, and modern dugouts may benefit from being covered to minimize water loss. Global studies have shown the effectiveness of physical covers at slowing the evaporation rate. Recently, California proposed covering its canals with solar panels to help conserve its water supply while also producing green electricity.
Source From: WorldEconomicForum