World Water Day 2023: Nature Based Solutions Connecting Cities and their Basins

By Katharine Cross, AWP Strategy & Partnerships Lead

I recently went out in a kayak on the Molonglo River in my new home of Canberra, Australia. It was a peaceful morning and although the water was pleasant, it had an unfortunate green tinge due to a recent algal bloom. Ongoing research has found that the contribution of high levels of phosphorus from the urban landscape in Canberra through stormwater runoff is one of the factors leading to algal blooms across the city’s lakes in summer months.

Changes in urban demographics and landscapes means that such waterways are under increasing pressure from pollution and competing water demands. Furthermore, these pressures affect the already-stressed drinking water, wastewater, and stormwater management systems within cities. Cities are influential nodes within the water system and their management approaches to water can reverberate across a basin, impacting different sectors.

In the case of Canberra, the problem of nutrients entering waterways are being mitigated through water quality infrastructure projects which consist of a variety of nature-based solutions (NbS) including ponds, wetlands, rain gardens and channel restorations. And further developments are underway this year, however citizen action is also needed in the way that residents deal with organic waste.

Beyond Technical Solutions

Addressing water issues often goes beyond technical solutions to shifting mindsets across government, private sector and the general public, such that all community members are committed to considering how their decision-making impacts water. Water challenges are not something that any single actor or group can solve. It requires collective effort across countries, basins, cities, villages everywhere.

Solutions require interconnected, holistic approaches to urban water management which connects cities with their surrounding basins. NbS are often an integral component of such solutions but require concerted actions between upstream and downstream communities.

The IWA-INBO Publication on Basin-Connected Cities explores how improved water stewardship within cities in partnership with the basin can address issues of too much water, too little water, or water at the wrong time. The handbook provides a practical reference on how to respond to the call to action for urban stakeholders to play a greater role in engaging in their hydrological basins. NbS are highlighted throughout the handbook as a “pathway to action” demonstrating how cities and their basins can actively cooperate. Many of the basin stories mentioned in this handbook include investment and application of NbS as part of linking cities with their catchment areas. Approaches include integration of NbS to improve the health of watersheds, reduce nutrient leaching and erosion/sediment runoff as a fundamental part of creating a basin-connected city.

Partnerships across boundaries

The source waters and their watersheds which sustain urban centres are very often shared beyond political and water management boundaries, which presents governance and coordination challenges. The focus on NbS as a shared approach can assist in formalising and activating partnerships across these boundaries, which provides a foundation for building trust across organisations, and can be used to solve local water challenges, pool expertise and resources, and leverage financial resources. For example, in the Júcar Basin in Spain, the restoration of rivers as they pass through cities is an opportunity for collaboration between the basin organisation and the local councils to jointly achieve environmental objectives. This includes development of green spaces of high ecological value in cities which can also provide a buffer to reduce risks of flooding.

Indigenous and Traditional Knowledge

Partnerships can enable engagement of diverse stakeholders, creating a dialogue on the options that NbS provide and how they can be best applied. This includes integrating local, traditional and indigenous knowledge which has often used NbS as part of water management practices. Indigenous people are often the most effective stewards of nature and recognise the interconnectedness across and between ecosystems including water. For example, In India and Bangladesh, riparian communities along the Ganga, Brahmaputra, and Meghna river basins have long implemented NbS and traditional strategies to tackle water security, floods, and riverbank erosion. This includes the use of structures made of bamboo to divert river flow to the centre to stabilise the banks — to tackle riverbank erosion.

Another example of the use of traditional knowledge is in Mexico City where there are projects which promote chinampas, a pre-Hispanic farming system to rehabilitate key ecosystem functions of the natural water cycle. These are plots of land surrounded by several channels for drainage: they are also known as floating gardens and are now used for floriculture and vegetable planting. This not only contributes to local food security but also provides green and blue infrastructure adapted to the metropolitan area of Mexico City.

Strategic Water Management and Financing Mechanisms

Developing a water management strategy or plan can include NbS, how they can be applied in practice, who will be responsible for design, implementation and maintenance, and how the costs will be covered. For example, in the Guandu river basin in Rio de Janeiro State, Brazil, Strategic Water Resources Plan for the Basin has been developed. It is divided into eight Thematic Agendas which provide a roadmap to how stakeholders can implement the agreed objectives for the future. One of the key Thematic Agendas is the Green Infrastructure Agenda has a range of initiative to support restoration and conservation of ecosystems related to water resources, and to increase the vegetation cover of the basin. This includes Water and Forest Producers project, in which 74 rural landowners participated in the conservation of 4,098 hectares of the Atlantic Forest biome and the restoration of more than 506 hectares of deforested areas. This was achieved through a payment system for environmental services which provided financial compensation to rural producers who were actively conserving forest, but also include recovery and protection of water sources.

The Guandu Basin example demonstrates how financing mechanisms or incentives can be structured to encourage investment in NbS and can be integrated into governance structures that allow downstream stakeholders to support and incentivise source watershed protection on lands owned and managed by those living upstream. Water Funds across Latin America  have been set up with water users including water utilities,  and industries pay into the funds to secure a safe and reliable water supply. The funds provide resources for forest conservation in water catchment areas, to improve water quality and quantity downstream. Investment in upstream NbS can help reduce the costs of operation and maintenance of urban water utilities, improve service quality and delay the need for expensive capital investment to improve or expand services.

Another example is in France where the use of water fees collected by water agencies has shifted from a sole focus on building treatment infrastructure to one that incorporates natural and urban ecosystems. Support is provided to local authorities for restoring and protecting aquatic environments, in particular waterways – revegetation, ecological continuity – and wetlands.

Accelerating change with Nature-based Solutions

NbS continue to be a connector to support management of water risks across catchments, and the increasing recognition of their role in sustaining water value.  The theme for this year’s World Water Day is “Accelerating change to solve the water and sanitation crisis”. With the ongoing UN Water Conference, voluntary commitments are being put forwards which aim to increase the action being taken on global to local water issues.  Many of these commitments incorporate and promote the use of NbS to achieve water security. As we move into the second half of the Water Action Decade we need to put these commitments into practice across our cities and their basins. As part of World Water Day, anyone can make a commitment to solve the water and sanitation crisis – share your actions, ideas and solutions on the UN Water platform: www.unwater.org/bethechange


This piece was originally published on the International Water Association website. Featured photo by Joshua Leong on Unsplash
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