Water shortage in urban areas is a perennial problem, and about 400 million people in urban areas deal with the lack of water. This problem is soon going to multiply as urban water demand is expected to increase up to 80% by 2050. One of the solutions proposed to deal with this crisis is to transfer water from rural areas to cities. In a recent study, an international team of researchers has investigated the prevalence of such water reallocations throughout the world to understand its drivers, conflicts and policy implications. Their findings were published in the journal Environmental Research Letters.
Water reallocation across the world is mired in controversy as rural areas, which primarily use water for agriculture, now fear a shortage of water. As the demand for water grows further in cities and rural areas, such disputes will only increase. On the other hand, it is believed that increasing the efficiency of irrigation can help rural areas beat the crisis.
“Any transfer of water from rural to urban areas is often opposed to as a net loss to rural communities; while in other cases, policymakers depend on the alternative myth that increasing irrigation efficiency will always deliver win-win outcomes for both donor and recipient regions”, remark the researchers. However, there is limited research about the coverage and impact of water reallocations at present, and this needs to expand to understand the status and trends of such redistributions.
In the current review, the researchers identify 69 urban areas across the world that receive water through 103 water reallocation projects. These projects involve approximately 16 billion cubic meters of water per year, which is almost equivalent to the annual flow of the Colorado River, and benefit an urban population of around 383 million.
The study found that most of the documented water reallocation projects are concentrated in North America and Asia, with the latter having 49 projects, including 18 from India. With 23 of the 41 projects implemented since the start of this millennium, Asia accounted for most of the new reallocation projects since 2000. The USA, India, China, Mexico and Iran had the highest number of identified reallocation projects. In most cases, they use both surface water and groundwater for reallocation.
The researchers also tried to understand what factors drove such reallocation projects. They found that water supply, demand or a combination of both are primarily responsible. A rising population and the growing demand for water was found to be the primary driver for about 80 reallocation projects. On the supply side, the limitations on the water supply, its unreliability and quality issues played an important role.
In some urban agglomerations in India, like Chennai, there are multiple water reallocation projects which have many donor regions. These projects receive water from both groundwater and surface water sources. In some cities like Hyderabad, such projects have paved way to rural-urban conflicts for water, while projects like Yettinahole River Diversion has raised biodiversity concerns.
“Reallocation can produce a range of outcomes including win-win, win-lose and lose-lose outcomes for donor and recipient regions”, say the researchers.
However, since data on the coverage, impact and compensation for rural donor areas are limited, it is difficult to estimate whether these reallocation projects are genuinely useful, equitable, and sustainable. Further research might help to understand under which conditions a ‘win–win’ outcome is feasible for cities and rural areas.