Improved stormwater management

"Siargao It Up" is the mangrove conservation programme in Del Carmen, Siargao Islands of the Philippines. The municipality of Del Carmen hosts the largest mangrove forest in the Philippines – consisting of 4,871 hectares as of 2018. This mangrove forest is the habitat of rare and endangered species of flora and fauna both in marine, wetland and terrestrial areas. This ecosystem helps maintain the island's ecological balance by providing rich breeding grounds for aquatic lives. Furthermore, the forest plays a key role in capturing and storing carbon and helps the Philippines to meet its goal of carbon emission reduction. In addition to creating habitats and storing carbon, the forest also protects the community from the inevitable effects of climate change disasters. Recently, in December 2021, it was able to protect the residents from the onslaught of Typhoon Odette. [1, 2, 3]

South Africa is struggling to provide services to the millions of poor people migrating to the major centres and living in informal settlements (shanty towns), built on land that was formerly used for agriculture or pasturage. Vegetation is sparse and the open spaces between the houses are generally of beaten earth. These areas face persistent challenges that undermine health and everyday well-being and increased disaster risk due to their poor design and lack of green infrastructure. Moreover, informal settlements are very vulnerable to flooding events, which affect the quality of life of the people living in them. Such a case is Diepsloot, a settlement in Johannesburg, where a team of researchers implemented a sustainable urban drainage system with the purpose of alleviating poor water infrastructure and addressing issues related to land erosion and environmental degradation. This research has been benefiting from the support of the local population through adaptive co-management and joint implementation of the intervention. (1,2)

The project focuses on encouraging residents of Rio de Janerio's Arará favela to install green roofs on their homes, primarily to reduce the urban heat island effect but also to harness the broader social, environmental, and economic benefits which green roofs can provide, "...from providing thermal protection and improving air quality to mitigating stormwater runoff pollution and saving costs for both residents and cities" (Refs. 2 & 3). The individual behind the project, Luis Cassiano Silva, further hopes that introduction of green roofs into the favela which help to improve residents’ quality of life and "describes the emotional benefits of incorporating green space into the favela landscape" (Ref. 2).

Delhi Development Authority (DDA) has established a network of Biodiversity Parks in Delhi with unique landscapes that harbour a diversity of plants, animals and microbes living in ecologically sustainable biotic communities and rendering multiple ecological services. Presently there are seven Biodiversity Parks developed by DDA located across the landforms of Delhi. These parks have a mosaic of habitats with rich floristic and faunistic diversity that function as a dynamic ecosystem. They have ecosystem processes such as organic matter decomposition, regeneration of plants, pollination, resting and nesting of birds and colonisation by other animals. The biodiversity parks in Delhi have proved to provide extreme essential services by creating ecological corridors and maintaining the genetic diversity in an urban setup. Furthermore, these parks have shown substantial potential in storing carbon and other pollutants and help in mitigating climate change. [2, 3]

The Chulalongkorn University (CU) Centenary Park was created to provide a green space for the city and celebrate Chulalongkorn University’s 100th anniversary. Located in the centre of shopping and commerce, the park is designed as a multi-functional “urban forest”, which serves as an oasis for the residents and visitors of Bangkok, who can spend quality leisure time in a lush and pleasant environment. The park includes constructed wetlands with rain gardens, retention ponds, an underground water drainage system and green roof areas. Opened in 2017, Chulalongkorn Centenary Park is the first critical piece of green infrastructure in Bangkok to mitigate detrimental ecological issues and disaster risk reduction. Unlike other public parks around the city, this one is the first in Thailand to demonstrate how a park can help reduce urban flood risks and help the city confront climate change, all while offering city dwellers a place to reconnect with nature. Designed with various ecological design components, the park reminds the city of ways to live with water rather than fear it. [1, 2, 4]

The Beddagana Wetland Park is located in Sri Jayawardenapura Kotte, Sri Lanka's administrative capital. The wetland park plays an important role in flood regulation and keeping the city cool during periods of extreme heat. The city is located in the Colombo district and the project contributes to the flood management goals of the Metro Colombo Urban Development Project (MCUDP). It demonstrates how a wetland can be preserved while promoting eco-tourism and improved livability in the city. The target area is located within the Sri Jayewardenapura-Kotte municipality and is a part of Parliament Lake. While focusing on the protection of the wetland habitat as a flood-retention area, the project also supports selecting investments aimed at the protection and landscaping of key areas within the target area to improve livability for local people living in and around the area, while providing access to much-needed recreational space. [2, 7]

The Bluebelt programme in Staten Island was implemented as it "preserves natural drainage corridors including streams, ponds, and wetlands, and enhances them to perform their functions of conveying, storing, and filtering runoff precipitation or stormwater". (Ref. 2). By delivering "stormwater to engineered systems that are designed to mimic natural streams and ponds which...meander or wind back and forth, the water slows down naturally" (Ref. 1). These actions are intended to "help control flooding, pollution and erosion" (Ref. 2), whilst also providing open green areas for both local communities and a "diverse habitat for wildlife" (Ref. 2). Beginning in 1990, the Bluebelt programme has undergone continual expansion, recognising that "as New York City prepares for rising sea levels and heavier rains due to climate change, Bluebelts offer a natural and effective solution for stable and sound stormwater management" (Refs. 2 & 4). The Bluebelt now includes approximately 400 acres of freshwater wetland and riparian stream habitat and 11 miles of stream corridor (Ref. 4).

The project has seen the "installation of rock structures to reduce the energy of the water that is drained by conventional rainwater galleries and the strategic planting of certain plant species that, through phytoremediation, can mitigate the diffuse pollution that affects the body of the river" (Ref. 1). In combination, "these solutions aim to prevent erosion and landslides on the banks, stop the siltation of the river, improve water quality and strengthen the linear park as a leisure space increasingly demanded by the population in its surroundings" (Ref. 1). A demonstration project which occurred under ICLEI's INTERACT-Bio project, the implementation of NBS has also been accompanied by other measures which saw Lake Cabrinha be de-silted, a walking path, benches, and playground be built and LED lighting be installed" (Ref. 1).

A rain garden has been implemented at the Fazenda Lagoa do Nado Municipal Park in Belo Horizonte. The rain garden has been created as "a solution that contributes to the runoff of rainwater, allowing the water to be filtered through vegetation and infiltrate into the soil", with this type of solution being recognised as a method which "recharge[s] the water table, increases biodiversity, improves the local microclimate and air quality" (Ref. 1). The rain garden has been created as a demonstration project within the wider INTERACT-Bio project which is led by the global Local Governments for Sustainability network, ICLEI (International Council for Local Environmental Initiatives) (Ref. 1). As summarised by President of the Municipal Parks and Zoobotany Foundation of Belo Horizonte, Sérgio Augusto Domingues, “This is an important experiment that enables solutions based on nature. The idea is that it, like other mechanisms, complements macro-drainage interventions, helping the city to be more resilient to extreme events related to climate change" (Ref. 3).
According to the Municipality of Belo Horizonte, the Multiannual Government Action Plan (PPAG) aims to implement 30 rain gardens in the municipality by 2025, each garden having an area of ​​150 square meters (Ref. 7).

Mauritania is one of the Sahelian countries most severely affected by the periods of drought occurring since 1968. The resulting desertification is exacerbated by human activities, which have compounded climatic factors, with direct consequences for an already precarious situation. Environmental degradation, responsible for the dangerous displacement of sand dunes in Mauritania, has wiped out homes, livestock and livelihoods throughout the desert country. In Nouakchott, Mauritania’s capital and biggest city, the coast are protected by a fragile wall of dunes at risk from natural erosion, sand mining, grazing of livestock on dune vegetation, and careless abuse of the landscape for leisure like dune racing. In this scenario, protecting the dunes is a priority, and the government is using World Bank financing to overcome the challenge. From a climate change perspective, the intervention addresses accelerating erosion that allows seawater to wash into the city, assaulting buildings, roads, fresh water supply and public space. From a biodiversity perspective, the intervention aims at sustaining the balance between the food for the livelihoods of the local population and the preservation of the rich coastal biodiversity. (1,2)