No resource is more vital to the survival of the human species than water. Beyond its obvious life-sustaining properties, water is a critical component for all aspects of human life. It feeds agriculture and energy production, drives industrial processes and transportation systems, and nourishes the ecosystems that we depend upon. Yet through waste and mismanagement, careless pollution, and ever-surging demand, humankind is careening toward a day when there will not be enough water for most people.
If we continue along our current path, the majority of humans will face chronic water shortages within two generations, widening the gap between the haves and the have-nots. City managers worldwide will be forced to decide how water should be deployed; and there will not be enough to go round. Nations will become even more vulnerable in the face of drought and extreme weather. And the pursuit of ever-dwindling resources will trigger land-grabbing and conflict, pitting nation against nation, and neighbour against neighbour.
It doesn't have to be this way. If we can focus on strategies that reduce demand and waste, establish practical policies, and apply smart technology for efficient use and monitoring, humankind can more sustainably manage this precious resource. But we must recognise that there can be no one-size-fits-all approach.
History can provide inspiration. Consider the ancient aqueduct system built in the 4th Century that supplied Constantinople with water from 250km away; or the great water systems of the early industrial era, such as the watersheds, tunnels, aqueducts and reservoirs that fed – and continue to feed – New York City. Built between the 1890s and 1940s, this infrastructure still sustains some nine million people with over 1.2 billion gallons of drinking water every day.
At around the same time, in the Netherlands, a massive earth dam project called the Zuiderzee and Delta Works transformed a shallow inland sea of 1,350 sq miles (3,500 sq km) into both fertile agricultural land and a coastal buffer that reduced flooding and provided fresh water. In that ambitious project, pumping stations were able to drain the enclosed land, or polder, within six months. Then, a network of drainage canals with smaller ditches that connected to larger ones were dug to further drain the soil, making it arable. Reeds were then seeded across the site to dry out the new land before they were replaced by rapeseed, and then rye, wheat, barley and finally oats. Ultimately, other crops could be planted on an area that was once covered with salt water.
Pure and simple
Rethinking the spatial distribution of resources is one strategy that can have tremendous impact on reducing demand, improving available volumes of grey water and enhancing efficiency of infrastructure. To this end, at the regional level, we would have to examine the symbiotic relationship between urbanisation and industry patterns.
We can make drinking water from water used by industry. For example, a new groundwater replenishment system in California’s Orange County creates near distilled water from secondary wastewater after filtering and disinfecting it with ultraviolet light. It has the potential to support 500,000 people. Additionally, it recharges a vast groundwater basin that supplies water to 20 cities and water agencies, serving more than 2.3 million Orange Country residents.
Treated water can also be put to industrial use. Such is the case in agriculture, particularly in arid climates. For example, Jordan’s Water Authority is presently treating domestic wastewater for re-use in agriculture; water is an incredibly precious resource in this part of the world.
Another widely used process for treating water that can expand our resources is desalinisation. However, desalinisation is energy-intensive and creates a hyper-saline brine that, when discharged, can harm aquatic ecosystems. Advances in this technology have moved from an energy-hungry distillation process to a reverse osmosis process (essentially, pushing saltwater through a membrane) and now to the utilisation of carbon nanotechnology, which also reduces energy use (though not waste). Researchers are also exploring practical ways to treat brine. Rather than discharging brine into the ocean, scientists are developing multiple mixing ponds as wetlands to reduce the toxicity of the brine as well as to cultivate habitat. Conceptually, this method of treatment has precedent. In Shanghai, in a project known as Houtan Park, artificial wetlands have been used to treat polluted waters along the city’s Huangpu riverfront.