Expected improved water quality

The Eagle Reef Project was launched to restore the health of Mobile Bay in response to habitat loss and declining fish populations due to the degradation of oyster and seagrass beds [REF 1, REF 6]. Originally planned in 2022 as an Eagle Scout service project by John Shell of Boy Scout Troop 147, the project has grown into a regional environmental initiative supported by Partners for Environmental Progress (PEP), the University of South Alabama’s Stokes School of Marine and Environmental Sciences, and municipalities such as the City of Fairhope [REF 3, REF 4, REF 7].
The project deploys preassembled mini reefs—constructed from plastic and PVC—beneath docks and piers across Mobile and Baldwin counties. These reefs, once colonised by filter feeders like oysters and barnacles, can filter up to 20,000 gallons of water daily and serve as habitats for fish, shrimp, and crabs [REF 1, REF 4]. The initiative aims to improve water quality, sequester nutrients, reduce algae, and restore marine biodiversity [REF 1, REF 6].
The Eagle Reef Project addresses critical coastal hazards, including water pollution, fish habitat loss, and the legacy of environmental disasters such as the Deepwater Horizon oil spill [REF 4]. It combines scientific monitoring, civic engagement, and scalable design to enhance the region’s climate resilience and ecological health [REF 1, REF 6, REF 7].

Bayou La Batre, also known as the seafood capital of Alabama, has been facing severe flooding problems, including the occurence of combined sewerage overflows. The Nature Conservancy has secured funding to install a green stormwater project in Bayou La Batre, adjacent to the library, sports fields and the community center. Alongside the aim of the green stormwater project to decrease flooding events in the community by infiltrating water, it also serves as an education and engagement project [1]

The Liberties is one of the most recognizable urban areas in Dublin and Ireland, strongly associated with old Dublin, working-class communities, and the brewing and distilling industries. While rich in history, cultural significance, and local stories, The Liberties faces numerous placemaking and quality-of-life challenges. The area continues to experience significant dereliction, a fragmented urban fabric, and a shortage of high-quality green spaces. For instance, tree coverage in The Liberties is sparse, with good-quality street trees only found in a few small areas, such as Gray St. and Reginald St., along the South Quays, Cornmarket, and near the fountain on James St. The area has approximately 1,200 trees, amounting to less than 5% canopy coverage.
In response to these challenges, Dublin City Council enacted The Liberties Greening Strategy in 2015. Building on the Liberties' Local Area Plan, this strategy aims to develop a network of new urban parks, improve access to heritage green spaces, and refurbish existing parks and play areas. It addresses multiple goals, including ecological connectivity, water management, flood risk reduction, air quality improvement, social cohesion, environmental education, and public health. This strategy is an initiative of the Parks and Landscape Services Division of Dublin City Council, in collaboration with the South Central Area Office and with input from Áit Urbanism + Landscape and Mary Tubridy & Associates.
Since its implementation in 2015, the strategy has resulted in the development of two new community parks, enhancements to several green spaces, and the greening of public spaces. It has also introduced measures to support food production in community gardens and allotments, revitalize ecosystems, strengthen water management, improve air quality, boost carbon sequestration through tree planting, divert water from the local sewer network, prevent flooding, and regulate heat. (1, 2, 3)

Pollution from roadways is often carried by rainwater into gullies, which then direct this runoff to the nearest watercourse, ultimately polluting local rivers and degrading water quality (1). To address this issue, Dublin City Council is exploring potential green infrastructure solutions to reduce roadway pollution in rivers, focusing on nine pilot sites within the Dodder catchment area (1). Green infrastructure has the advantage of treating pollutants before they enter rivers or watercourses, which can significantly improve water quality in the area (1).
In addition to enhancing water quality, green infrastructure helps manage flood risks by slowing water flow to rivers, which can lessen the frequency and severity of flood events (1). These green spaces also foster biodiversity, creating more pleasant and ecologically supportive environments for the community (1). As an added benefit, green infrastructure serves as an important climate change adaptation strategy (1).
Upon completion of these pilots, Dublin City Council plans to expand successful methods to other locations across the city and potentially further afield (1). The project will involve creating new green spaces, enhancing existing ones, and transforming certain hard surfaces, all of which will contribute to protecting the Dodder and Santry rivers. By treating roadway runoff before it reaches the rivers, the initiative will also offer valuable benefits to the local community (2).
The proposed changes will be designed to support health and well-being, provide informal play areas, attract desirable wildlife, reduce flood risks, and help urban areas adapt to the impacts of climate change (2). The Council also plans to monitor the performance of these green infrastructure measures to assess their effectiveness in filtering pollutants from roadway runoff (1).

To reduce the risk of urban flooding, the city of Seville, through its metropolitan water company Emasesa, established several "sustainable urban drainage systems". One of the pilot locations is on the Avenida de las Ascociaciones de Vecinos, where a rain garden complemented by an infiltration zone was established. The main aim of the project is to reduce the risk of flooding, but the system can also improve the urban landscape by offering green space, preventing desertification and reducing pollutants carried by runoff [Ref. 1-4]. After implementation, the project was shown to be effective during heavy rain [Ref. 5]. The system can store up to 34 m2 of water and reduce flow rates to the sewage network by 69 % and the total runoff to sewage by 93 % [Ref. 3-5]. The project was initiated and led by Emamesa, while two different companies were employed to design and construct the system [Ref. 1, 2, 6, 7]. The total budget of the project, which also included some renovations of grey infrastructure along the street, was 165000 EUR [Ref. 1].

The Far West Detroit neighborhood faces significant challenges with its aging infrastructure. The neighborhood’s stormwater and sewer systems are combined into a single system that is only capable of handling a limited volume. During heavy rain events, the system's capacity is exceeded, causing excess stormwater and untreated sewage to overflow into the Rouge River, which negatively impacts the environment (Ref. 1).
Detroit is investing $40 million in a transformative stormwater management system in the Far West neighborhood near Rouge Park. Described by the Detroit Water and Sewerage Department as the largest project of its kind, it will redirect 98 million gallons of rainwater and snowmelt into two new detention basins and a renovated sewer system. The new wastewater system is expected to significantly reduce water volumes in Detroit’s combined sewer system during heavy rainfall and to provide flood relief for approximately 1,200 homes that have experienced flooding in recent years. This expansion, informed by community feedback, marks one of the city's most notable investments in green infrastructure to improve its overextended wastewater management system.
The project has been planned through extensive studies and community coordination since 2016, with construction set to occur in three phases, extending through 2026. Crews broke ground on the South Basin, North Basin, and sewer overhaul in July 2022, and progress is reportedly on track. In addition to the basins, the stormwater management initiative includes neighborhood improvements to enhance recreational opportunities for residents and visitors alike. Planned enhancements in Rouge Park will introduce wetland spaces with native flora, creating greener, more inviting areas in the community for residents to enjoy (Ref. 2).

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 Santa Gilla lagoon, a crucial wetland in the Cagliari metropolitan area of Sardinia, has been the focus of several interventions aimed at restoring and preserving its natural and socio-economic functions. The overarching goal of these projects is to rehabilitate the lagoon's ecosystems, improve public accessibility, and promote sustainable economic activities such as eco-tourism and fishing. One significant intervention is the restoration of pedestrian and cycling paths around the lagoon, managed by CACIP (Consorzio Industriale Provinciale di Cagliari) in collaboration with the Metropolitan City of Cagliari. With over two million euros in funding, this project aimed to recover the original profiles of the lagoon's embankments, while removing waste from the area and enhancing the paths for non-motorized mobility (2). Another crucial development was the legal action taken by the Corpo Forestale (Forestry Corps) in 2020 to address illegal constructions and pollution along the lagoon's eastern shores. This action included the sequestration of areas used for illegal fishing activities, where hazardous materials and waste were improperly disposed of, leading to environmental degradation​ (1). Furthermore, environmental groups have made continuous efforts to address illegal dumping near the lagoon, particularly along the SS 195 highway. These groups have actively sought the intervention of local authorities to initiate cleanup operations and enforce regulations against illegal waste disposal​ (4). The projects were implemented primarily to address the significant environmental hazards facing the Santa Gilla lagoon, including pollution from illegal dumping, habitat degradation due to unauthorized constructions, and the overall loss of biodiversity. These activities also aimed to mitigate the socio-economic risks posed by the deteriorating environmental conditions, such as the decline in tourism and sustainable fishing practices (1,2,4).

"Urban Natural Area Ciric" is an initiative aimed at designating the forest and lakes of the Ciric area, located on the outskirts of the city of Iași, as an Urban Natural Area. To achieve this goal, the initiating organizations—NGO Civica and the Ornithological Association of Iași (SOR)—have developed a comprehensive report focused on the Ciric natural area, which monitors species and habitats while identifying pressure points on biodiversity and necessary conservation actions, as well as the benefits these areas provide.
In the Ciric area, various flora and fauna species have been identified, with some holding high protection status (14 bird species) or being of community importance and conservation interest. However, this ecological richness faces threats, as factors such as rapid urbanization, water pollution, and waste disposal have been identified as significant risks to the ecosystems.
In response to these challenges, the NGO aims to collaborate with the municipality to create protective municipal laws that will not only recognize the area as an Urban Natural Area but also ensure its inclusion in development plans. This partnership seeks to establish regulatory measures and strategies that will safeguard and enhance the biodiversity and ecosystems of Ciric. Additionally, the organizations have highlighted the social and physical benefits of the area for residents, including flood regulation and prevention, pest control, provision of clean air, and recreational and scientific opportunities.
To further raise support and awareness for their efforts, SOR and Civica conduct guided tours, educational workshops, and photographic exhibitions. They have also set up two informational panels in the area that highlight the biodiversity of Ciric. Furthermore, the two NGOs have partnered with regional organizations to create the "Rețeaua națională de arii naturale urbane" (The National Network of Urban Natural Areas) and have received funding from the EEA Grants. (1-8)

Rainwater management in Gdańsk presents significant challenges due to the city's hydromorphological conditions, including high groundwater levels and steep terrain. These factors, coupled with the periodic inefficiency of the storm sewer system and the intensification of extreme weather events such as heavy rainfall, have necessitated innovative solutions. Gdańsk has responded by implementing a climate change adaptation policy that promotes the use of open drainage systems, including small retention facilities like rain gardens. These gardens help mitigate the risks associated with excessive rainfall while enhancing urban sustainability.
The first rain garden in Gdańsk was established in the Stogi district at the Flood Control Warehouse on Kaczeńce Street. This facility collects and utilizes rainwater from nearby paved surfaces, aiming to manage rainfall of at least 30 mm during intense, short-term downpours. Utilizing a variety of perennials such as marsh marigold, common loosestrife, comfrey, hemp agrimony, common calamus, and arrowhead, the garden retains and filters rainwater naturally, increasing efficiency and ecological benefits. Rain gardens absorb water up to 40% better than traditional lawns. They reduce rainwater runoff, mitigate flood risks, filter pollutants, improve biodiversity, and enhance urban air quality while lowering temperatures.
The garden was created as part of a broader investment in the Flood Control Warehouse in Stogi, a facility opened in 2017 at a cost of over PLN 5 million. Strategically located near the Sucharski Route and the Martwa Wisła tunnel, the warehouse supports rapid response to flood emergencies, storing over 100 types of equipment, from shovels to large generators. This combination of infrastructure and green solutions demonstrates Gdańsk's commitment to urban resilience and environmental sustainability. (1-4)