For the first time, Brazil hosted the world launching of the United Nations World Water Development Report. Audrey Azoulay, Director-General of UNESCO; Joakim Harlin, Vice-Chair of UN-Water; and Erik Solheim, the Executive Director of the UN Environment Program attended the event, which publicly stated the importance of nature-based solutions (NBS) for water. For Stefan Uhlenbrook, the Coordinator and Director of the UN World Water Assessment Programme (WWAP), reservoirs, irrigation canals and water treatment plants are not the only water management instruments at our disposal. “We can’t wait for nature to solve all problems itself, but we can get inspired and use it in favor of the planet.”
As the name itself suggests, nature-based solutions are those that use or simulate natural processes to address contemporary challenges, including those associated with water management. Its objectives are, for instance, to increase water availability (soil water retention and groundwater recharge are nature-based solutions), improve water quality (natural and artificial wetlands, and riparian forest buffers) or reduce water-related disasters and climate change risks (restoration, flood plains and roof gardens).
That is: nature-based solutions are ecological processes driven by vegetation and soil in forests, pastures, humid areas, as well as in agricultural and urban landscapes, which play an important role in water movement, storage and transformation.
A good example took place in the state of Rajasthan, in India, which experienced one of the worst droughts in its history in 1986. Over the following years, Tarun Bharat Sangh, an NGO, worked alongside local communities to set up water harvesting structures and regenerate soils and forests in the region. The initiative to create a nature-based solution, led to a 30% increase in forest cover, groundwater levels rose by several meters and cropland productivity improved.
The main point of the report is to recognize that water is not only an isolated element, but an integral part of a complex natural process involving evaporation, precipitation and absorption of water through the soil. The presence and extent of vegetation cover across grasslands, wetlands and forests influences the water cycle and can be the focus for actions to improve the quantity and quality of available water.
“For too long, the world has turned first to human-built, or “grey”, infrastructure to improve water management. In so doing, it has often brushed aside traditional and Indigenous knowledge that embraces greener approaches. Three years into the 2030 Agenda for Sustainable Development, it is time for us to re-examine nature-based solutions (NBS) to help achieve water management objectives”, writes Gilbert Houngbo, Chair of UN-Water and President of the International Fund for Agricultural Development in the foreword of the report.
Here are five examples of nature-based solutions
1) The System of Rice Intensification, originally introduced in Madagascar, helps restore the hydrological and ecological functioning of soils rather than using new crop varieties or chemical products. It enables savings of 25 to 50% in water requirements and 80 to 90% in seeds while raising paddy output by 25 to 50%, depending on the region in which it is implemented.
2) New York City has been protecting its three largest river basins since late 1990s with greener solutions. While vegetated walls and roof gardens are perhaps the most recognizable examples, others include measures to recycle and harvest water, water retention hollows to recharge groundwater and the protection of watersheds that supply urban areas. In addition NYC saves more than US$ 300 million yearly on water treatment and maintenance costs by disposing the largest unfiltered water supply in the USA.
3) China recently initiated a project titled “Sponge City” to improve water availability in urban communities. By 2020, China will build 16 pilot Sponge Cities across the country. Their goal is to recycle 70% of rainwater through greater soil permeation, retention and storage, water purification and the restoration of adjacent wetlands.
4) Over the past few years, Ukraine has been experimenting artificial wetlands to filter pharmaceutical products from wastewater. There is evidence that wetlands alone can remove 20 to 60% of metals in water and trap 80 to 90% of sediment from runoff. Wetlands only cover about 2.6 % of the planet but play a disproportionately large role in hydrology. They directly impact water quality by filtering toxic substances from pesticides, industrial and mining discharges.
5) Chile announced measures to protect its coastal wetlands after the tsunami of 2010. This is because wetlands also act as natural barriers that soak up and capture rainwater limiting soil erosion and the impacts of certain natural disasters such as floods.
Content published in March 21, 2018