Water management (SDG 6)

Banyuwangi International Airport in East Java is the first green airport in Indonesia and was recognized with an award from the Aga Khan Award for Architecture (AKAA) in 2021-22, the world's oldest and most prestigious architecture awards (1,2,3,4). This project was designed and implemented by Architect Andra Matin in 2018 as a corporate social responsibility project for the Banyuwangi Regional Government, Java, Indonesia (1,2,4). The project building was extensively inspired by the houses of the local Osing tribe (1,2). The project aimed to embody a highly efficient passive design, with its remarking green roof feature of a total area of 4765m2 that is planted with grass and routinely maintained (1,2,3,5,6). The green roofs act like a sponge for heat, light and water and conserve energy by maintaining a constant temperature inside the building, and as a result, the airport does not require air conditioning in the main area (5). The green roof of the airport improves air quality as it captures airborne pollutants and atmospheric deposition, and the plants on green roofs also filter noxious gases (5). The eco-friendly airport terminal construction utilizes 'Fast Flow Siphonic System', especially for conventional roof drainage (5). The regional government declared a 10 km radius 'No Development Zone' around the project, protecting the existing paddy fields and villages, which is an exceptional move given the general tendency to exploit land around airports commercially (1,2). The current airport site caters to around 300,000 passengers annually and allows for future expansion to accommodate up to 3 million passengers without encroaching on the No Development Zone (2).

Revitalizing Informal Settlements and their Environments (RISE) is one of the pilot projects carried out in the Batua neighbourhood (1.9 km2 area) of Makassar City (119 km2 area), province of South Sulawesi in Indonesia, which was commenced in 2017 and concluded in 2022 (1,2,3). Batua neighbourhood (six settlements of around 1,600 people) was the first demonstration site for this project which was completed in 2019 (3,4,5). The main challenge was that many households who lived in informal settlements lacked access to centralized urban infrastructure and faced threats from climate change (3,4). The project was proposed to reduce the impact of climate change on marginalized communities in Makassar by providing localized, water-sensitive interventions that addressed issues related to sanitation and water management (1,2,3,4). The introduction of water-sensitive solutions enabled targeted communities to recycle wastewater and rainwater, restore natural waterways, improve water quality, and reduce vulnerability to flooding (3,4). The RISE program initiative integrated nature-based solutions like wetland restoration, bio-filtration gardens (the process of using beneficial bacteria to clean water on a molecular level to remove contaminants), stormwater harvesting, filtration paths and new sanitation structures to improve wastewater management and diversify water resources through community-driven development (1,2,3,4).

The green roof development forms a 400-meter-long floating green ribbon above the SM North EDSA mall in Quezon City, Philippines. [3] It boasts a 15000m2 area filled with 55 species of native trees, bushes, and flowers that thrive in the local climate, and it relies on stored rainwater runoff to sustain its plant life. Visitors can access the mall via entrances located within the garden's openings and tunnels leading to shops and cafes nestled beneath the botanical landscape. A meandering pathway guides visitors through the space, which features various entertainment options. The garden provides a unique and innovative space for mall-goers and city dwellers to relax and interact with nature. [1,2]

Indonesia’s peatlands are among the most vulnerable ecosystems on Earth and also have significant potential as carbon sinks (1,2). Fire risk in Sumatra's peatland areas is high due to canals that were dug for logging and plantation development (1,2). The Sumatra Merang Peatland Project was thus launched to restore the area as the massive forest fire in 2015 destroyed thousands of hectares of biodiverse tropical forest (1). This project includes restoring more than 22,900 hectares of peatland rainforest in the Merang region, located within Musi Banyuasin Province, South Sumatra in Indonesia (1,2,3). The project targets the Merang biodiversity corridor, one of the largest and deepest peat swamps in South Sumatra, which protects an area more than 3.5 times the size of Manhattan (New York City) (1,2,3). This project is a part of the Althelia Climate Fund and was implemented on the ground by Indonesian Companies named PT Global Alam Lestari (GAL) and Forest Carbon (1,2,3,4,5). The project aims and contributes to climate change mitigation and ecosystem resilience by peat rewetting and reforestation, protecting biodiversity and working with local communities to build and improve livelihoods (1,3).
The first stage of the project is considered completed and is considered to achieve positive impacts already, but it still aims to upscale certain activities until 2025 (3,4,5). The total lifetime of the project extends to 2062 (4).

The rehabilitation of the Klang River or Selangor Maritime Gateway (SMG) is a project that was put into effect in 2018 by the Selangor State Government. The project aimed to transform the Klang River, considered the most polluted river in Malaysia, into a beautiful and clean river which can be a new source of economic growth in the state of Selangor, Malaysia. The river has been polluted with trash, plastic bottles, and sewage, which harmed the vegetation and the aquatic ecosystem (1). The project proved to be highly complex as it included rehabilitation of the river through several green solutions such as the creation of a community park, the conservation of various species of mangroves, and the implementation of riverfront greens as a measure of slope protection. The intervention is set to be developed on an area of 56 Km along the Klang River corridor. It is expected to promote and support the integrated management of river basins with particular emphasis on ensuring that biodiversity and wetland conservation and community considerations are incorporated into river basin management that includes the development of eco-city (3,5,6). Furthermore, the project intends to conduct an awareness campaign about river cleaning and rehabilitation activities to educate the public on the importance of rivers and the environment in our lives while consequently highlighting the critical state of pollution faced by the River (1).

The ‘City of 1,000 Tanks’ project offers a holistic solution to the problems of floods, water scarcity and pollution in Chennai (Ref. 1). The project's primary objective is to develop a "Water Balance Model" for the city, which involves collecting rainwater, treating wastewater and runoff pollution with decentralized nature-based solutions, as well as prevent climate-change-induced droughts and saline intrusion due to sea-level rise (Ref. 1, 2). This is achieved through developing various nature-based water management solutions and improving the recharge capacity of traditional temple tanks (Ref 1).
The project began in 2018, following the call for action event of the "Water as Leverage for Resilient Cities Asia" (a bilateral program spanning several Asian countries). The Water Balance Model is developed as a strategy with an incremental implementation process (Ref 1, 2). The project started with pilot projects and then progressed to flagship projects before full city-wide implementation (Ref. 3).

A 7-hectare pilot public project, the Tebet Eco park is located in South Jakarta in a neighbourhood that is densely populated. Previous to the intervention the park was in an acute state of deterioration and prone to floods as well as ecological degradation, as the park is streamed by a river which made it only more susceptible to heavy rains. As such, the municipal authorities of Jakarta planned to revitalize the area by " increasing the hydraulic capacity of existing canal, improving site-wide pedestrian connectivity, and adding new recreation program". This meant that the park was transformed by planting and conserving new and older trees, as well as using vegetation and natural embankments. Furthermore, the implementer planted riparian vegetation to improve water quality by filtering and cleansing surrounding runoff, which also enhanced the site's biodiversity. Besides these elements, a thematic garden, a forest buffer, and a community garden were implemented complementing the entire eco-design that the park aimed for. The park's rehabilitation focused greatly on the human element as it was paramount to provide maximum benefits for park users, the surrounding natural habitats and species, as well as increasing the land value of the area. (2,3,7)

In 2018, the Bulat Utemuratov’s Foundation began reconstruction works at the main Botanical Garden in Almaty at the request of the Institute of Botany and Phytointroduction and with the support of the governor of Almaty city [1, 5, 6]. The goal of the project was the restoration of the botanic garden with preservation of its original green character and the modernization of its infrastructure [2, 5]. Taking into account the special status of the Botanical Garden and the high public interest in the reconstruction project, the Foundation ensured full transparency to the public. Taking public recommendations into considerations, the schematic design of the reconstruction was approved in the autumn of 2018 [6]. The project also aimed to do no harm to the existing flora and fauna of botanical gardens, and apply new technology to provide long service life to the garden [1, 4].

To achieve the project's goals, the water supply system was restored, drip and auto irrigation systems were created. Around 174.3 thousand plants were planted, including more than 1300 trees. Additionally, 50 thousand sq.m of roads and paths were repaired, lighting systems and video surveillance systems were installed, and the garden furniture was renovated [1]. The project also resulted in the development of three new entrance pavilions with an electronic ticketing system. A mobile application with a garden map and a description of the green areas has been developed [5]. Special attention was paid to the accessibility of all zones of the Botanical Garden for low-mobility groups. [1, 4, 5, 6].

Confirming the success of the project, within three months after the reconstruction was completed, over 210 thousand persons visited the Almaty Botanic Garden [6].

Spanning over 32000 square meters and featuring a landscaped rainwater catchment basin [5], the Rain Garden was created in 2014 in the Nuvali district of Santa Rosa. The garden offers an example of eco-friendly urban planning in the Philippines, as the Nuvali district is an eco-city itself with residential, business and commercial areas. Besides the Evozone Rain Garden, Nuvali also has various nature amenities, including a multi-functional lake, cycling and hiking paths, a wildlife and bird sanctuary and camping grounds. The Evozone Rain Garden was established in a commercial development area and it includes spacious open areas and cycling paths, along with the footbridge and view deck and adjacent to the manmade lake in Nuvali [2]. The Rain garden also serves as a rainwater catchment basin, rainwater harvesting system, and fire reserve, providing recycled water for landscaping, irrigation and other non-potable water uses [1]. In addition, the garden has been developed to serve as a habitat for various bamboo varieties and birds [4], also making the garden an ideal birdwatching spot [3]. The EvoZone Rain garden is free and open to the public [2].

Kempegowda International Airport Bengaluru (KIAB)'s new terminal 2 is an environmentally friendly initiative that uses innovative methods to maintain ecological sustainability using native plants (Ref 1, 2). The terminal was built on four guiding principles: technology leadership, being a terminal within a garden, environmental and ecological stewardship, and a celebration of Karnataka’s rich heritage and culture. Through the "terminal within a garden" project, the aim was to create a calming and relaxing space for passengers using greenery for visual appeal as people pass through the airport (Ref 1). Hanging gardens, trees, and green walls are the primary nature-related features included in the terminal and an outdoor greenbelt around the terminal. The airport uses native plant species, including trees, flowering plants, and shrubs (Ref. 2).
The terminal area also includes water bodies, cascades, and miniature waterfalls to maintain the natural atmosphere. The terminal also has extensive rainwater harvesting and groundwater recharge facilities (Ref 1). Other sustainable goals in the terminal area include energy saving, water conservation, waste management, and pollution control measures (Ref 2).