Public national budget

The Waliwa project, launched in 2017 by the municipality of Sainte-Luce, is a collaborative effort dedicated to restoring marine biodiversity, enhancing the ecological balance of the bay area, revitalizing the local ecosystem and supporting sustainable economic activities. By focusing on marine biodiversity conservation, Waliwa addresses several critical environmental challenges. The project helps mitigate coastline erosion, support the blue economy through artisanal fishing and tourism, and foster an environmentally friendly culture among the local community.
So far, the Waliwa project has implemented three initiatives: it restored the Gros Raisin backshore to address erosion and provide nesting sea turtles with protected space (Ref 4). The project also intervened to restore the Pont Café pond, which was covered in Salvinia Molesta, preventing the intake of oxygen and hampering its role as a water filter, habitat for species and flood regulator .
Furthermore, the project has conducted studies and raised awareness about the challenges posed by wastewater management on the health of municipal water bodies. Through these efforts, Waliwa is working to create a more sustainable and resilient marine environment for future generations. (Ref 4, 5, 6; 12)

The Cagliari Canal project is an initiative aimed at revitalizing and transforming the urban and natural landscape of the Cagliari Metropolitan Area in Sardinia. The project is rooted in the city's strategic metropolitan plan and seeks to restore and enhance the navigability of the Terramaini-La Palma canal, which had become disused and neglected over time​ (3,4). The primary goal of the Cagliari Canal project is to develop a connected, innovative, and sustainable urban environment by re-establishing the canal as a green and blue infrastructure​ (2). It aims to provide alternative, sustainable mobility options, improve connectivity between municipalities, and enhance the natural and urban environments. It strives to foster a sense of community by creating a shared space for residents and integrating modern amenities that align with environmental sustainability (1,4). It involved a highly participatory process, emphasizing community involvement from the initial planning stages. The Metropolitan Authority of Cagliari, in collaboration with local stakeholders, launched a series of consultations to gather public input on the canal's design and function​(3). These consultations were part of a broader initiative called LabMet, the Metropolitan Laboratory for Innovation, which facilitated the collection of ideas and feedback (1). The project was partly developed in response to the increasing environmental challenges faced by Cagliari, including the need to adapt to climate change. The canal's revitalization is seen as a key measure for enhancing the city's resilience to climate-related risks, such as flooding and heat waves​(1). By restoring the canal and its surrounding areas, the project aims to mitigate these risks through improved water management, reducing pollution, and the creation of green spaces that can absorb excess rainwater and provide cooling effects​ (2)

Located between the Rotes Rathaus, Karl-Liebknecht-Straße, Nikolai Quarter, Spreeufer and the television tower, the old founding centre of Berlin is one of the capital's most important urban open spaces. This open space between the TV tower and the Spree is being redesigned on the basis of an international open space planning competition and many years of public participation. With further development, this touristically significant location in the historic centre of Berlin will undergo a climate-resilient redesign and upgrade with great design and functional quality. (Ref. 1)
The listed areas of the Rathausforum and the Marx-Engels-Forum will in future be connected to form a continuous ribbon of open space that runs from Alexanderplatz to the Spree. Central areas will be unsealed and green spaces will be created that can be used in a variety of ways, which will also be attractive places to spend time and improve the microclimate. Trees and shrubs will be planted on already existing and new green areas. The aim is to respectfully consider the numerous visible and hidden historical references and at the same time transform the site into a sustainable urban open space that combines a high quality of recreation, sustainability and culture. Next to plants, a new rainwater management system is being implemented that stores rainwater and uses the created green spaces to evaporate water. Playgrounds and a water fountain are further additions to a new recreational area. (Ref. 3; Ref. 4; Ref. 5)
The project is characterized by a years-long participation process. Around 10.000 citizens participated in feedback rounds, workshops, dialogues, and information sessions in which they could voice they wishes and ideas for the area. The project is implemented and organized by the state-owned company Grün Berlin, which engage with various stakeholders since 2015. Preparations for the construction start in late 2024 and the project is expected to be finished in 2030. (Ref. 5; Ref. 9)

The former Kulturpark Plänterwald, once the only permanent amusement park in the GDR, closed in 2001 due to declining visitor numbers. Over time, the 23-hectare site became a ‘lost place,’ falling into disrepair. In 2014, the state of Berlin reacquired the area, and two years later, Grün Berlin initiated its redevelopment with a sustainable development concept that places significant emphasis on rainwater management.
The project’s goal is to avoid discharging rainwater into the sewer system and instead manage all precipitation on-site. This approach addresses both heavy rainfall events and extreme drought conditions, creating a sustainable rainwater management system. A central element of this concept is the historic but dried-up water basin located near the iconic Ferris wheel. Plans include redesigning and reactivating the basin, incorporating terraces and a shallow water zone, transforming it into a key part of the rainwater cycle while providing an attractive recreational and adventure area. (Ref. 1; Ref. 2)
In the future, the water basin will no longer be purely decorative but will serve as a critical artificial water reservoir. To support this function, it will be equipped with a natural horizontal filter system featuring reeds for rainwater purification. Pre-treated water will flow into the newly designed 3,000-square-metre basin near the Ferris wheel. Rainwater collected in the basin, along with water stored in cisterns throughout the park, will irrigate the site’s vegetation. This innovative approach ensures sustainable water use and contributes to the ecological revitalization of the park. (Ref. 1; Ref. 3)
By integrating sustainable rainwater management into its redevelopment, the former Kulturpark Plänterwald is being transformed into a resilient and environmentally conscious space, combining historical preservation with modern ecological practices.

This project aims to increase water retention capacity in the landscape around urban areas and promote biodiversity by restoring wetlands and natural streams in the forested areas on the island of Hisingen in northern Gothenburg. Many wetlands and streams in the area have been drained or otherwise affected by human activity, reducing biodiversity, increasing the risk of floods and droughts and causing greenhouse gas emissions from peatland. The goals of the project are to reduce the risk of floods downstream, reduce the effects of dry periods, increase groundwater infiltration and benefit species living in and around wetlands and streams in the forest [Ref. 1-3]. The Swedish Anglers Association has initiated the project in cooperation with the City of Gothenburg and the environmental engineering company Miljöteknik I Väst AB [Ref 1]. The project's first stage is a continuation of an earlier project to make an inventory of wetlands and their status [Ref 1, 2]. For the second part, 6,9 ha of wetlands and streams on land owned by the city were restored [Ref. 1, 3]. The project will lead to further efforts in wetland restoration around Gothenburg [Ref. 2, 4].

Located in the municipality of Morne Rouge, the Domaine d’Émeraude was once an agricultural site but was transferred to the Martinique Regional Natural Park (PNRM) in the early 2000s. It underwent significant renovations in 2005 to transform it into a sanctuary for Martinican biodiversity, reflecting the need to protect and conserve the island's unique ecosystems. In 2011, it opened its doors to the public, serving as an important educational resource that raises awareness about the island's historical, natural, and cultural heritage (Refs 4, 7, 8).
Today, the site encompasses 25 hectares protected from anthropogenic pressures and is primarily characterized by a humid tropical forest environment, which makes up 80% of the area (Ref 7). It is home to over a hundred native species (Ref 4) and offers nearly 4 kilometers of walking trails accessible to both adults and children, complete with recreational stops and educational amenities.
The Domaine d’Émeraude was designed to enhance the conservation of native species while developing sustainable economic activities that benefit the local community. Moreover, the site emphasizes the well-being that forested areas provide to visitors, highlighting that "the air can be heard, the smells can be savored, and the sounds can be experienced. The freshness of the place is a source of change and relaxation..." (Ref 4).

In Berlin, at the palace park and garden Charlottenburg, approx. 40 to 70 horned Gotland sheep are used to maintain the grass fields and meadows. The project is part of a garden and landscape conservation programme that is to be seen as a contribution to practical nature conservation by the Prussian Palaces and Gardens Foundation Berlin-Brandenburg, which manages the park. From May to November, the sheep are grazing on the palace property, whereby the exact length of time the sheep are kept and the duration of the project depend largely on the developing weather conditions. This is because prolonged drought significantly reduces the growth of the grasses. (Ref. 1)
The garden had already been grazed earlier in its history, but no longer in the post-war period. The garden was created by Electress Sophie Charlotte in 1695. (Ref. 3) Since 2018, sheep can be found again in the park space where they graze on extensive meadows with groups of chestnut, lime, maple, oak, beech and solitary trees. At the beginning of May, they move into their first station there, usually the meadow in front of the late baroque-classical Belvedere tea house. Once this has been grazed, they move on to the next meadow; with an area of 55 hectares, there is plenty of pasture. (Ref. 4)
Sheep from his flock also graze on the green flat roof of the Max-Schmeling-Halle in Pankow, the palace garden of Sanssouci and other public and private patches of land around Berlin. Reasons to use sheep over machinery for the maintenance of the park space are monetary and a reduce loss of biodiversity. Sheep are cheaper compared to machinery, the needed labour and wear, and also don't kill insects living in the fields as machinery does. Furthermore, the sheep dung fertilises the grass area, sheep limit the spread of invasive plants and are more gentle to the soil. At the same time, palace visitors enjoy observing the sheep and can learn about them in guided tours. (Ref. 4; Ref. 6)

The Fenkell Stormwater Project in the Brightmoor neighborhood of Detroit is an initiative led by the Detroit Water and Sewerage Department (DWSD) to mitigate the impact of heavy rain events on the local sewer system. By transforming 92 Detroit Land Bank Authority (DLBA) parcels into 24 bioretention gardens, the project aims to significantly reduce street flooding and basement backups in the area. These gardens, spread across approximately 50 acres of mostly vacant land, utilize permeable soils and landscaping techniques to absorb excess rainfall, which helps prevent the overloading of the city’s combined sewer system. This is particularly important in reducing combined sewer overflows (CSOs), which occur when the system's capacity is exceeded during heavy rains, leading to untreated stormwater and sewage being discharged into the Rouge River.
The project is expected to manage and treat about nine million gallons of stormwater annually, making a significant impact on both the neighborhood’s infrastructure and the environment. In addition to the bioretention gardens, the project includes the partial removal of Blackstone Street between Keeler and Midland streets to further enhance stormwater management.
Community engagement has been a critical component of the project, with residents of Brightmoor and Minock Park participating in meetings to share their preferences for the types of trees, plantings, and other features. The DWSD will maintain the gardens under its Green Stormwater Infrastructure (GSI) program, which already includes 19 other similar projects across the city. The project is currently in the construction phase and is expected to be completed by the end of 2024, modernizing Brightmoor’s stormwater infrastructure and providing long-term environmental and community benefits.
(Ref.1-3)

The Kikås dump is a landfill in Mölndal, south of Gothenburg, where an area has been permanently covered with a sealing layer and inert material. This project aimed to utilise the area to increase biodiversity by establishing flowering meadows and an insect hotel, creating a habitat for wild bees, butterflies and birds [Ref. 1-3]. The City of Mölndal initated the project and sowed meadow flowers, established sand beds for burrowing insects, an uneven, rocky terrain and a large insect hotel [Ref. 1, 3]. The area is also meant to be a destination for recreation and learning about biodiversity. The Insect Hotel is marketed as the largest in Sweden, and it includes information signs and an outdoor classroom. The project is meant to raise awareness about biodiversity and ecosystem services such as pollination [Ref. 1, 4-6]. The area borders natural areas such as forests and wetlands and is meant to have positive ecological effects in the border zones. The project will contribute to the environmental goals of the city, in particular, "a rich plant and animal life" [Ref. 3]

The beach of Vétiver, located in the municipality of Case-Pilote, is one of the most important nesting sites for the critically endangered hawksbill turtle (Eretmochelys imbricata) in Martinique. It is also a nesting ground for the green sea turtle (Chelonia mydas), another endangered species. As one of the last minimally urbanized beaches in the North Caribbean of Martinique, the site plays a vital role in the conservation of these species. In addition, fishing restrictions in the area significantly reduce the risk of turtle mortality caused by accidental capture in fishing gear, which is the leading cause of human-related sea turtle deaths in the Antilles.
However, the site faces several stressors that hinder successful nesting. The surrounding vegetation is severely degraded due to invasive alien species, and much of the shrub and tree cover has disappeared from the backshore, where turtles prefer to nest. Without adequate vegetation, hatchlings are left exposed to the heat. Additionally, the beach is frequently disturbed by local residents and visitors for recreational activities. With no designated parking area, cars often park directly on the beach, compacting the soil and further limiting the chances for vegetation to recover or turtles to dig nests. This compaction forces turtles to lay their eggs closer to the shoreline, increasing the risk of nests being washed away by heavy swells.
In 2022, the non-profit organization "Asso-mer" and its partners launched the Véti’Vert project on a previously neglected public green space. Through environmental restoration efforts, they created a nesting enclosure on the backshore to mitigate these stressors and improve the conditions for sea turtle nesting. The project also engaged with local residents to increase the chances of success (Refs 1-3).