Environmental Integrity

Nature-Based Solutions for Water - Part One

What are Nature-Based Solutions?

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TITLE: Nature-Based Solutions for Water – Part One: What are Nature-Based Solutions?

RESOURCE: The United Nations World Water Development Report 2018

CORPORATE AUTHOR: United Nations Water Assessment Programme

COPYRIGHT LICENSE TYPE: Corporate Commons https://creativecommons.org/licenses/by-sa/3.0/igo/. The text was edited for readability.


The 2018 edition of the United Nations World Water Development Report (WWDR) focused on opportunities to harness the natural processes that regulate various elements of the water cycle. These opportunities have become collectively known as nature-based solutions (NBS) for water. This is not merely a "good idea" (which of course it is), but an essential step to ensuring the long-term sustainability of (1) water resources and (2) the multitude of benefits that water provides, from food and energy security to human health and sustainable socio-economic development.

There are several different types of NBS for water, ranging in scale from the micro/personal (e.g. a dry toilet) to landscape-level applications that include conservation agriculture. There are NBS that are appropriate for urban settings (e.g., green walls, roof gardens and vegetated infiltration or drainage basins) as well as for rural environments which often make up the majority of a river basin’s area.

Maximizing nature’s potential in helping to achieve the three main water management objectives – enhancing water availability, improving water quality, and reducing water-related risks – will require creating an enabling environment for change, including suitable legal and regulatory frameworks, appropriate financing mechanisms, and social acceptance. We remain confident that, with the political will to do so, current obstacles - such as the lack of knowledge, capacity, data and information about NBS for water - can be effectively overcome.

NBS support a circular economy that is restorative and regenerative by design.  Such an economy promotes greater resource productivity to reduce waste and avoid pollution, including through reuse and recycling. NBS also support the concepts of green growth or the green economy, which promote sustainable natural resource use and harness natural processes to underpin economies. The application of NBS for water also generates social, economic and environmental co-benefits, including improved human health and livelihoods, sustainable economic growth, decent jobs, ecosystem rehabilitation and maintenance, and the protection and enhancement of biodiversity. The value of some of these co-benefits can be substantial and can tip investment decisions in favor of NBS.

But despite a long history of, and growing experience with, the application of NBS, there are still many cases where water resources policy and management ignore NBS options – even where they are obvious and proven to be efficient. For example, despite rapidly growing investments in NBS, the evidence suggests that this is still well below 1% of total investment in water resources management infrastructure. Water resource management remains heavily dependent on human-built (‘grey’) infrastructure. The idea is not necessarily to replace grey with green infrastructure, but to identify the most appropriate, cost-effective and sustainable balance between grey infrastructure and NBS considering multiple objectives and benefits.

In some situations, nature-based approaches can offer the main or only viable solution (for example, landscape restoration to combat land degradation and desertification). For different purposes only a grey solution will work (for example, supplying water to a household through pipes and taps). In most cases, however, green and grey infrastructure can and should work together. Some of the best examples of the deployment of NBS are where they improve the performance of grey infrastructure. The current situation,with aging, inappropriate or insufficient grey infrastructure worldwide, creates opportunities for NBS as innovative solutions that embed perspectives of ecosystem services, enhanced resilience, and livelihood considerations in water planning and management.