Water management (SDG 6)

The Tagus Estuary Linear Riverside Park is a significant environmental and recreational project in Vila Franca de Xira. As part of a broader urban regeneration initiative, the park aimed to enhance the natural and cultural landscape by promoting ecological regeneration while providing public access to the Tagus River (Ref 1). Created in 2013, the park has won several international awards and since then, the park has undergone several extensions. In 2017, another 700-meter walkway was added towards Santa Iria, and the inhabitants of this urban area of Vila Franca de Xira widely use it (Ref. 6). The park covers over 14 hectares and includes pedestrian and cycling paths, environmental education facilities such as the Bird Observatory, and the Environmental and Landscape Interpretation Centre (Ref 2).
Recently announced in 2023, the park's newest expansion is set to extend the riverside trails further, creating a continuous route from Lisbon to Alhandra (Ref 5). With future phases planned, the project is expected to significantly increase public interaction with the riverfront and its biodiversity (Ref 5). In this new project phase, the Vila Franca de Xira Municipal Council begins the requalification and environmental and landscape conservation of another section of the riverfront of the Municipality of Vila Franca de Xira, between Alverca and Sobralinho, covering an extension of approximately 4.9 km and an area of ​​approximately 14.1 hectares (Ref. 7). The extension of the park will be developed similarly to its existing infrastructure. New paths for pedestrians and cyclists will be created using elevated wooden structures (walkways). In total, two new cycle-pedestrian trails will be created – Trilho das Comportas (3.32 kilometres long) and the Trilho dos Salgados (594 metres long) –, and the Trilho do Tejo will be extended by a further 990 metres (Ref. 5).

In an architecturally important area of Berlin, situated between the Landwehr Canal, the Kulturforum (the Berliner Philharmonie and the Berlin State Library) and the new construction on Potsdamer Platz, a combination of green and grey infrastructure has been realised to minimise the burden on Berlin’s existing water infrastructure.
Green and non-green roofs harvest annual rain, which flows through the site’s buildings and is used for toilet flushing, irrigation, and fire systems. The roofs retain and then release water to the large on-site buffer pond, which has five underground storage tanks. Next to the roofs, a series of urban ponds and connecting canals have been implemented, with a combined area of approximately 1.2 hectares. They are filled with rainwater, creating an oasis for urban life. Vegetated biotopes are integrated into the overland landscape and serve to filter and circulate the water that runs along streets and walkways. The lake’s water quality is excellent, forming a natural habitat for animals and cooling the surroundings, while fresh water usage in the buildings has been reduced. (Ref. 1; Ref. 2; Ref. 3; Ref. 6)
The project was implemented in the 1990s as part of the development of Potsdamer Platz in the wake of the reunification of Germany. Several architects collaborated on the implementation that was completely privately funded. Beyond its ecological and technical features, the site is a blue natural site in the heavily built city centre of Berlin and allows people to linger and enjoy natural features. The drainage system won several sustainability prices and is considered a successful integration of nature and technology-based mechanisms to foster climate change adaptation. As the rainwater system stores rainwater in underground tanks and ponds, the urban sewage system is relieved during heavy rain, and water can evaporate. Therefore, the small water circle is closed, and the microclimate is cooled. (Ref. 2; Ref. 6)

The Green and Blue Axis (Eixo Verde e Azul, EVA) is an inter-municipal green corridor project connecting the municipalities of Sintra, Oeiras, and Amadora through a 15-kilometre green ecological axis along the Jamor River (Ref 2). It aims to renaturalize the river, improve water quality, and control flooding while promoting sustainable mobility through pedestrian and cycling routes (Ref 5). The project also enhances public access to green spaces and cultural heritage sites, such as the Queluz National Palace (Ref 6). EVA supports the Lisbon Metropolitan Area’s regional strategy for climate change adaptation, risk prevention, and low-carbon economy (Ref 4). Funded by the European Regional Development Fund and municipal budgets, the project has an overall investment of €11 million (Ref 1). EVA exemplifies inter-municipal cooperation, overcoming policy conflicts to achieve shared environmental, social, and economic goals, making it a model for integrated territorial development (Ref 4). The project’s long-term impact includes reduced carbon footprint and increased territorial cohesion.

In 2020, the Metropolitan City of Cagliari launched a project to enhance flood resilience and ecological integrity in the Mannu-Cixerri river system in southern Sardinia. The river traverses several communes within the metropolitan area, ultimately feeding into the Santa Gilla Lagoon, a vital wetland ecosystem west of the city.
The project, with a budget of €21 million, focuses on three key communes: Assemini, Decimomannu, and Uta. Rather than solely emphasizing structural flood defenses, the initiative integrates nature-based solutions (NbS) to mitigate flood risks while restoring riverine ecosystems. The Metropolitan City of Cagliari, in collaboration with the Sardinian Regional Public Works Department, is responsible for its implementation.
Key interventions include reinforcing and revegetating embankments, improving water flow along the Rio Mannu, and constructing new levee sections in a manner that enhances natural water retention. Additionally, the project involves upgrading bridges to facilitate better floodwater management. These measures align with the Sardinian Flood Risk Management Plan (PGRA) and aim to reduce flood hazards while promoting ecological benefits.
The project timeline began with a two-year preparation phase for the Preliminary Design Document, followed by a year-long tendering process for construction. These efforts represent a crucial step toward long-term flood resilience and environmental sustainability in the region. (Ref. 1, 2, 3)

The project to redevelop Archipelagos Square in Cagliari aims to transform this key urban space, which serves as a gateway between the city and its coastal areas, into a more functional and aesthetically pleasing environment. Currently, the area lacks cohesive design, leading to unregulated use and its transformation into an informal parking lot. The redevelopment will address these issues by enhancing the pedestrian experience and reducing vehicular traffic. Improvements in public comfort and safety will include better rainwater drainage, the removal of architectural barriers, and the creation of accessible pathways for all.
This project emphasizes environmental sustainability and the preservation of the local landscape. Key interventions include revitalizing green spaces, safeguarding native vegetation, and removing invasive species. Integrating walking and cycling paths will improve connectivity between the city, Marina Piccola, and Poetto beach, fostering outdoor recreational activities. A designated eco-system filter will recreate the natural dune environment, blending pedestrian areas with the surrounding landscape.
Funded by the Fondo Sviluppo e Coesione (FSC), the project has a total budget of 3 million euros, with construction lasting 10 months starting in October 2023. The redevelopment reflects the broader goals of Cagliari’s administration to promote sustainable urban mobility and improve the public realm, contributing to the city's vision of becoming a hub for nautical sports while enhancing the overall quality of life for residents and visitors (Refs. 1, 2, 3 & 4).

The Metropolitan Linear Park is a project initiated by the national government of Bolivia, funded by the Inter-American Development Bank (IDB) (1-8). The proposed park will be located along a disused railway corridor between the cities of La Paz and El Alto, spanning 18.2 km (8, p. 8). The project involves the construction of a linear park, divided into five sections, each with distinct objectives, uses, and designs (8, p. 9). This large-scale initiative aims to improve access to public spaces in La Paz and El Alto, enhance connectivity between the two cities, protect surrounding biodiversity and natural spaces, and strengthen resilience to and mitigate the effects of climate change (3 & 8, pp. 11-12).
To achieve these goals, the project design includes outdoor sports and recreational facilities, pedestrian and cycling circuits, as well as the restoration of parks, squares, and public spaces adjacent to the park corridor (8, p. 9). Some features include balcony corridors, flower and food-producing urban gardens, and viewpoints (5). The project also plans for the re-vegetation of the area with native species and aims to stop the environmental degradation of surrounding natural environments, such as the Pura Pura forest, which has been suffering from ongoing deforestation and waste dumping (8, p. 9). These efforts are expected to increase and support biodiversity in the area (7 & 8, p. 12).
Additionally, the project emphasizes social inclusion, with policies designed to incorporate women, indigenous populations, and persons with disabilities (8, pp. 7-8). The park is intended to raise awareness about climate change and biodiversity, ultimately improving the quality of life and health of nearby residents and the citizens of La Paz and El Alto (8, p. 13).

A new park is being planned for the Cypress Shores area in Mobile (Ref 1). Five civil engineering students from the University of South Alabama contributed to the design of the park (Ref 1). This collaboration offers students practical experience while providing city designers with innovative ideas for the site (Ref 2). The design emphasizes sustainability and cost-effectiveness (Ref 3). The project will feature a small park and boat launch on a 5.6-acre plot (Ref 1) located within a residential neighbourhood (Ref 3).
The park's societal goal is to improve public access to Halls Mill Creek, giving the community a new way to enjoy the waterway, and this focus aligns with the Mobile Bay National Estuary Program (MBNEP) goals (Ref 3). Historically, the property was used as a shipyard with a nearby railroad crossing (Ref 1), marking its transition from an industrial site to a public park.
Several amenities have been identified for the park’s development, including a boat ramp and kayak launch, a boardwalk adapted to sea-level rise, a pavilion and gazebo designed for flood resilience, a wetland nature trail with solar lighting and educational signage, and composting toilet restroom facilities (Ref 3). An armoured shoreline will be implemented to withstand medium water currents, and wave action will be constructed. Additionally, a living shoreline will be restored with local plants (Ref 3). While the project is still in its preliminary design phase, the timeline for completion is estimated at 12 to 18 months (Ref 1). The designers highlighted a potential trade-off, noting that an influx of visitors to the park could disturb the surrounding residential area (Ref 3).

The Recovery of Cienaga Juan Polo project is primarily aimed at reopening the natural mouth of the Manzanillos to restore water flow between the sea and the Juan Polo coastal wetland, which has been affected by human activities leading to high salinity and water stagnation issues (ref 2). The project is led by Fundacion Serena del Mar. Environmental and social sustainability are core components of the project design, which has included extensive community consultations since 2013. These consultations have resulted in agreements covering employment opportunities, education, and infrastructure development (ref 2). Key implementation activities include the reforestation of mangroves and targeted interventions to address ecological degradation, such as increased salinity, water stagnation, and biodiversity loss (ref 2). The project also seeks to enhance the quality of life for surrounding communities by restoring traditional economic activities, particularly fishing, and integrating sustainable urban planning elements such as canals, sluices, and navigable waterways. These features are designed to support the development of a "blue corridor" for aquatic mobility within Serena del Mar (ref 2, 3). In addition, it also contributes to local capacity building through environmental education programs that engage community members, researchers, and NGOs in biodiversity monitoring and sustainable practices​ (ref 1).

The Pantanos de Villa Wildlife Refuge is a natural oasis in the heart of Lima. It is considered a marsh of international Ramsar importance, as it is home to a large number of species of flora and fauna. It includes 5 bodies of water with about 210 species of birds, 13 species of fish, and 5 species of amphibians and reptiles, among others (1). It was created in 2006, by Supreme Decree N°055-2006-AG, which established the definitive category for the Pantanos de Villa, under the name of The Pantanos de Villa Wildlife Refuge (2). This protected area was established over an area of 263.27 ha, and its main goal is to conserve a representative sample of the Marshes of the Subtropical Pacific Desert, including important plant communities, as well as migratory and resident avifauna, focusing mainly on species with some degree of threat (1, 2, 6).
In 2016, a Master Plan was approved aimed at strengthening the conservation of the biological diversity of this coastal marsh and ensuring conditions to promote inter-institutional cooperation and participatory management, including neighbours, authorities, municipalities and interested institutions (2).
This Master Plan establishes environmental, economic and cultural indicators defined to be met over 5 years. These are focused on protecting water resources, conserving migratory and resident bird species, ensuring the conservation of the cattail, promoting tourism and recreational activities, fostering environmental awareness activities and engaging citizens in the management of the Refuge (2)
This plan seeks to confront a series of threats that endanger the conservation of this ecosystem. Among the main problems are the illegal extraction of natural resources, such as cattail; the improper use of the space for activities such as bonfires, consumption of illicit substances and pet walks; the change in land use due to urban expansion; pollution from effluent discharges and solid waste disposal; and illegal fishing (2)

The Stora Amundö and Billdal archipelago nature reserve is in the southernmost part of the City of Gothenburg. The proximity to the city makes it a popular recreational destination, with about 73000 visitors each year. In 2018, the area was protected as a nature reserve to preserve its recreational, natural and historical values. The status as a nature reserve prohibits any exploitation and other harmful activities in the area. The area of the reserve is 1103 ha, of which 259 ha is land area and the rest is water [Ref. 1-3]. The management of the reserve includes promoting recreational and educational activities by creating new entrances, paths and signs, as well as holding guided tours. The management also includes restoring and improving terrestrial ecosystems such as grasslands through mowing and grazing and deciduous forests through selective clearing. A wetland has been restored to promote biodiversity further [Ref. 2, 4]. The reserve was created and is managed by the City of Gothenburg, the process of creating it involved consultation of stakeholders such as land owners, government agencies and NGO's [Ref. 1]. Some local landowners disagreed with the borders of the nature reserve having an impact on their land, leading to an appeal that was ultimately denied [Ref. 5, 6]