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 society. 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 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 polder (land enclosed by embankments) 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.
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 patterns of urbanisation and industry.
We can make drinking water from water that’s already been 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.
Conversely, treated water can also be used for industry. 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 water resource 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 utilization 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.
Water management strategies should also be implemented down to the level of industrial sites, where improvements can build on existing networks of freshwater tributaries, tidal estuaries, infrastructure and engineered ecosystems.
Many types of industry and energy production – including hydropower, mineral extraction and mining or fuel production – rely on vast quantities of water. Cooling towers re-circulate water with the sole purpose of getting rid of heat, and in the process, release large amounts of water to the atmosphere via evaporation and through contaminated water. That’s a lot of liquid coming out of what are typically over-stressed water budgets. In some recent projects, designers instead employ recycled grey water. For example, at the UK’s Peterborough Power Station, waste water from a nearby sewage treatment plant is used instead of drinking water. In Phoenix, Arizona, the Palo Verde Nuclear Power Plant is the world’s only atomic power station not located adjacent to water. Instead, it uses treated sewage water to cool steam. In the Netherlands, a chemical plant in Terneuzen accepts more than 2.6 million gallons of household wastewater each day.
Through a project developed for a new city in Saudi Arabia, the design team Koetter Kim suggested cooling towers could be replaced by re-circulating water through green space such as wetlands, walls of vegetation, agriculture and fountains. The aquatic landscapes rely on the same evaporative and convective heat transfer processes used in the towers, but allow the water to be re-circulated. Moving this process from a tower into a chain of cooling landscapes adds green spaces to the environment which can be used in a number of ways.
Urban areas increasingly have to think of greener infrastructure that harnesses natural processes. If these spaces fail to perform – because of a lack of understanding about their functioning – the results can be costly and environmentally damaging. Therefore, we have to be able to measure the water-saving performance of these projects. Increased interest in urban hydrology and stormwater management shows how badly our engineered landscapes fit into the land where they were built. We need to observe, assess and understand the performance and resilience of these ecosystems. The MillionTreesNYC Initiative, for instance, is a “designed experiment”, which adds scientific analysis to urban planning, design and engineering. The public park includes on-the-ground research plots to see where trees are needed. Such hypothesis-driven research will promote the type of urbanisation that adds to the health, safety and welfare of residents and their environment. Such projects can look at how city agriculture and nearby industrial practices relate, and how they can be adapted to conserve water.
Routine modification of land through collaborative involvement in so-called “working landscapes” can aid learning, align with the values of local populations, and influence decisions on environmental issues. This process – and the shared responsibility it generates – enables these projects to serve as a testbed that reveals better ways to confront the complex problems of climate change and its impact on stressed communities. In the UK, the London Wetland Centre functions as such a working landscape; its habitats are built into clay-lined pools and filled using a pumping system built in the 1890s for former reservoirs. The pools can be filled and drained, which helps cater to specific species of birds.
The task of conserving water can also be addressed on a smaller scale, beginning with improvements to architecture and homes. Our homes can become management tools for water conservation measures. The built center for the Women for Women International’s Women’s Opportunity Centre in Koyonza, Rwanda, includes a rain water capture and supply system that supplies water to the site throughout the year. Composting toilets add nutrients for local farmland for lacking nitrogen and phosphorus. Sand filters and UV filter drinking water. Grey water goes straight back to kitchen gardens.
In 1949, the environmental scientist Aldo Leopold wrote: “We abuse land because we see it as a commodity belonging to us. When we see land as a community to which we belong, we may begin to use it with love and respect.” The same can be said for water.
We need to work toward developing an appreciation of water, not merely as a commodity, but as a lifeline of human civilisation.