- There is a move towards nature-based solutions to manage water scarcity and water quality challenges
- Nature-based solutions provide multiple environmental, economic, and social co-benefits
- In the context of marine and freshwater management, nature-based solutions can mitigate emissions, create more liveable cities, and restore degraded ecosystems
In the 21st century, society is faced with a variety of climatic and non-climatic challenges that can lead to abrupt, and in some cases, an irreversible environmental change that adversely impacts human development. For instance, climate change is increasing the frequency, intensity, and magnitude of disasters, rapid population growth and urbanisation are resulting in ecosystem degradation from excessive water withdrawal, and land-use changes are leading to degradation of natural habitats along waterways.
One approach to addressing these challenges is to increasingly rely on engineering solutions, which are designed and managed to be simple to implement, easy to replicate and provide predictable outcomes. However, ‘grey infrastructure’ is costly economically and environmentally; for instance, it is often capital intensive in building, operating, maintaining, and replacing. Also, as grey infrastructure is mainly built to address a specific water management problem it can amplify risks downstream. For example, canals may magnify floods downstream, resulting in harm to life and damage to infrastructure. Environmentally, grey infrastructure often degrades water quantity and water quality from ecosystem degradation; for example, large-scale water transfer schemes damage aquatic health while increasing competition for scarce water resources downstream. As such, there has been a turn to more long-term economically and environmentally sustainable nature-based solutions (NBS) that provide equivalent or similar benefits to ‘grey’ infrastructure.
In addition to managing water scarcity and improving water quality, NBS provides multiple co-benefits including restoring natural habitats, cleaner air and reduced temperatures in urban areas, energy efficiency in buildings or water treatment, lower carbon emissions from less water requiring treatment and carbon sequestration by vegetation, increased property values, and green jobs and green growth.
Climate Change Mitigation
In the context of climate change mitigation, NBS are referred to as ecosystem-based mitigation (EbM), which encompasses a diverse set of mitigation approaches including the sustainable management of forests, use of native assemblages of forest species in reforestation activities, conservation and restoration of peatlands and wetlands, protection of the ocean sink, improved grassland management, and environmentally-sound agricultural practices. In addition to mitigating greenhouse gas emissions, EbM provides a range of co-benefits including less biodiversity loss because of slower climate change.
Case 1: UK’s Largest Seagrass Restoration Project
Sky Ocean Rescue, WWF, and Swansea University have launched the largest seagrass restoration project ever in the UK. The project involves planting seagrass seeds over two hectares in Dale Bay, Pembrokeshire. Seagrass captures carbon from the atmosphere up to 35 times faster than tropical rainforests. The freshly planted seagrass is expected to trap up to half a ton of carbon dioxide per hectare each year once fully established by ‘sponging’ carbon dioxide from the atmosphere. In addition to trapping carbon dioxide, the seagrass will act as a nursery for a variety of marine life, including endangered seahorses and sea snails. In total, by restoring two hectares, the seagrass will be able to support around 160,000 fish and 200 million invertebrates.
Enhancing Sustainable Urbanisation
In the urban context, NBS can be applied as green infrastructure (GI), which is a strategically planned network of natural and semi-natural areas that are designed and managed to deliver a wide range of environmental, economic, and social benefits. GI varies in scale and scope and includes the levels of buildings, public spaces, water bodies and drainage systems, and green corridors. GI provides three main opportunities: first, GI supports economic development in urban areas, second, urban planning that incorporates GI has a positive environmental impact, and third, GI contributes to the social dimension of urbanisation, such as increasing people’s happiness and general health.
Case 2: Waterwise Perth
Recognising the value of nature in reducing the urban heat island effect and creating liveable, green, and sustainable places, the Government of Western Australia has released the Waterwise Perth Action Plan which sets out the direction for transitioning Perth to a leading Waterwise city by 2030. The Waterwise Perth Action Plan calls for an increase in green space in urban environments through a variety of initiatives, including the Waterwise Greening Scheme. This is a scheme where Waterwise Councils can receive up to $10,000 in funding to support a variety of Waterwise greening initiatives including green street programs and demonstration Waterwise gardens, for example, reclaimed public open space gardens, all of which provide multiple co-benefits including improving water quality, improving community health and well-being, increasing biodiversity, and cooling local communities.
Restoring Degraded Ecosystems
Freshwater ecosystems are impacted by a range of activities that modify water quantity and lower water quality, including land-use change and intensification, deforestation, and drainage. Changes in the land and water use in a catchment can affect river and stream morphology and change the rates of water flow. Riparian buffers can be established next to waterways to restore the natural aquatic environment and capture runoff, nutrients, and sediment. The vegetation used can include grasses, shrubs, and/or a variety of trees. They reduce the impacts of flooding through temporary storage, interception, and the slow release of heavy rains. Overall, riparian buffers reduce sediment and nutrient load, improve water quality, reduce stormwater runoff as well as provide wildlife habitat and recreational opportunities.
Case 3: Pennsylvania’s Riparian Forest Buffer Grant
Pennsylvania’s Department of Conservation and Natural Resources (DCNR) provides river conservation grants that focus on protecting and enhancing the conservation or recreational value of Pennsylvania’s waterways. Grants are available to help increase riparian forest buffer establishment state-wide to improve the health and diversity of local ecosystems by filtering pollutants, improving bank stability, and reducing erosion and flooding. DCNR supports both conventional riparian forest buffers and multifunctional buffers that provide benefits beyond conservation.
The Riparian Forest Buffer Grant has a minimum award of $50,000, with funds provided by DCNR to not exceed 50 percent of the approved project cost. Finally, applicants who undertake a buffer project must be willing to enter into a landowner agreement to protect the riparian buffer for at least 25 years.
NBS come in all shapes and sizes, helping to mitigate climate change, improve the liveability of cities, and restore the health of waterways.