In the Philippines and India, mangrove forests are being expanded in conjunction with existing breakwaters on coastlines to protect against storms and flooding. Similarly, in South Africa, wetlands are being restored to recharge groundwater and protect from drought water-insecure cities, like Cape Town.
Communities globally are encouraged to scale up nature-based solutions and integrate them into modern infrastructure. A 2021 report published by the International Institute for Sustainable Development (IISD) concluded that such an approach could save the world $248bn annually in construction costs for expanding infrastructure.
Governments around the world are investing in research and development of nature-based solutions, while global financial institutions such as the World Bank are actively involved in funding projects utilising such approaches.
As urban planning scholars studying water, urbanisation, and climate justice in small and medium-sized South Asian cities, we agree that nature-based solutions hold promise. But we also suggest caution. Our work in Khulna, a region in southern Bangladesh facing multiple ecological crises, provides one example of how integrating nature-based solutions can lead to complicated outcomes that help some communities while harming others.
Khulna’s ‘nature-based solution’
In 2011, Khulna, Bangladesh’s third-largest city, was facing severe water scarcity. Along with declining groundwater and pollution, there was rising saltwater intrusion into its freshwater sources. The local government had several options to address the crisis.
It could build a desalination plant to treat water from nearby rivers. But such installations are known to be ecologically harmful. For example, a paper from the Canadian-based Institute for Water, Environment, and Health notes that desalination plants discharge 142 million cubic metres of hypersaline brine every day globally. That is enough to cover the US state of Florida under 30cm (12 inches) of brine, which can be toxic and incredibly harmful to marine life.
Another option the local government had was implementing tougher water controls on residents and businesses. This would mean asking residents to conserve water and industries to drop water-intensive practices and invest in rainwater harvesting systems. Such water conservation policies can be hard to implement and politically unpopular.
To avoid the negative effects of a desalination plant and potentially unpopular water conservation policies, the local government opted to construct a “climate-proof” water supply system for which it managed to obtain foreign funding from the Asian Development Bank and the Japanese International Cooperation Agency (JICA).
This water supply system was planned to extract water from the Madhumati River in the village of Mollahat, 40km (25 miles) northeast of Khulna, and bring it to the city. During the rainy season, water would be processed directly by a water treatment plant and then provided to consumers. During the dry season, when the salinity of the Madhumati is high, the water would be mixed with low-salt water collected in a reservoir during the rainy season to decrease its salt concentration before being sent to the plant.
Policymakers hoped this “nature-based solution” of mixing water would address future problems as rising seas will continue to increase salinity levels in Khulna’s water. The framing of the new water infrastructure as climate- and nature-friendly enabled the local government to justify the construction of the expensive project.
The new water infrastructure, which was finished in 2019, indeed benefitted Khulna residents. It increased access to piped water from 23 percent of households to 65 percent and provided water access to some informal settlements that did not have any previously.
The problem the ‘solution’ created
The popularity of the new water system in Khulna was apparent in the interviews we conducted with the city’s residents. They reported that women could now get water from taps at assigned times instead of queueing up for hours to collect water from tube wells.
However, the reports from Mollahat were completely different. During our fieldwork in 2018, one of us spoke to a local resident, Mohammad Liton, who said he barely slept through that year. Liton was overcome by worry about the rising salinity and low water levels in the Madhumati River, which had begun to impact his livelihood. Liton argued that the Khulna water project had reduced the availability of water for fishing and rice cultivation in the Mollahat area.
In January 2017, Liton and other residents of Mollahat staged a protest against the project, which was impacting the lives of thousands of farmers and fisherfolk living in the village, but the authorities did not address their concerns.
The project’s environmental impacts statement, which was required by the government of Bangladesh and the foreign donors and which was completed in 2011, focused narrowly on the water site and accounted for construction as the only impact on Mollahat.
According to representatives of the Bangladesh Environmental Lawyers Association (BELA) we interviewed, the scale of the assessment inaccurately accounted for the Madhumati River watershed as existing only in Bangladesh. The river is a tributary in the complex Ganges River system, with flows coming from the Ganges in neighbouring India.
The Madhumati River has been heavily affected by the upstream construction of the controversial Farakka Dam in India’s state of West Bengal, which diverts its waters. The dam has made the river watershed much more sensitive temporally and ecologically and thus, the additional burden of drawing water for the Khulna project has significantly strained the river resources and affected Mollahat and other communities along its basin.
Approaching nature-based solutions with caution
Khulna’s water project should be a cautionary tale – one that can teach policymakers lessons about what they should and should not do when implementing nature-based solutions.
In this case, while industries and households of Khulna reaped the benefits of the projects, residents of Mollahat bore the costs. This could have been avoided if the local authorities had consulted with village dwellers at the construction site and downstream while evaluating the impact of the project. Their feedback could have been used to adjust implementation.
The local authorities should have also aimed to distribute benefits equally among the population of the city and the nearby rural communities. For example, they could have asked industries to conserve water, which would have decreased the strain on the Madhumati River and significantly lessened the impact on the Mollahat community.
When green approaches are combined with infrastructure, local authorities must ensure that no harm is done to adjacent communities. Fixing the water problem of a city should not come at the cost of the devastation of rural communities.
As nature-based solutions are scaled up, we urge policymakers, donors, and communities to be more cautious. Infrastructure projects, like the one in Khulna, must minimise harmful impacts and help tackle inequalities at the local level and across regions.
The views expressed in this article are the authors’ own and do not necessarily reflect Al Jazeera’s editorial stance.