Executive Summary

The Black Sea's boundary encompasses its tributary catchments and extends to the Mediterranean via the Marmara Sea, with limited mixing due to bathymetry and the narrow Bosphorus Strait. The impact of human activities is evident in the declining biological resources, diminishing species diversity, and degraded landscapes within the Black Sea. Eutrophication, pollution, and unsustainable fishing practices have collectively eroded the aesthetic and recreational value of this ecosystem, pushing it perilously close to collapse. Plastic pollution is exacerbated by limited water exchange and pollutant runoff from major European rivers, highlighting the need for comprehensive management strategies to preserve this delicate ecosystem. The Black Sea's largest meromictic (extreme minimal intermixing) basin status, anoxic lower layer, unique islands and ecosystems, and prevalent plastic pollution further characterize its complex state. Further insights are available in the Blueing the Black Sea Program’s Turning the Tide of Pollution Regional Report.

Over the years, policy advancements, improved monitoring, and enforcement recognition have led to progress in managing Black Sea pollution. Economic shifts after the Eastern Bloc's collapse led to better wastewater management and reduced pollutant loads. However, recent studies predict that regional development could reverse progress, returning the Black Sea to its eutrophic state of the 1980s. Inflowing European rivers like the Danube, Dniester, and Dnieper have notably influenced this trend. Fortunately, as the region experienced socioeconomic growth and political change in recent decades, collaborative institutions like the Black Sea Commission and initiatives like the Common Maritime Agenda have emerged, addressing pollution, conservation, shipping safety, fisheries management, and integrated coastal zone management. Coastal planning, supported by ministerial declarations and strategic plans, have fostered sustainable coastal zone use. Efforts like the Regional Action Plan on Marine Litter and the Black Sea Integrated Monitoring and Assessment Programme reflect ongoing environmental commitments in the Black Sea Region.

A complex civic and business landscape spanning multiple countries, requires a comprehensive understanding of stakeholders and their needs for successful implementation of NBS. To achieve this, a series of workshops was conducted, introducing stakeholders to NBS benefits and the project's goals. The engagement primarily focused on littoral countries due to ongoing geopolitical events. Stakeholder analysis was crucial, identifying key players, regional organizations, expert communities, and international financial institutions. The Mendelow matrix helped classify stakeholders based on power and interest. Regional entities like the Commission on the Protection of the Black Sea Against Pollution and the Black Sea Economic Cooperation were key partners. National ministries responsible for environmental and economic sectors were pivotal, and local engagement involved expert communities. International financial institutions were recognized for their role in fostering economic development and regional collaboration. This comprehensive stakeholder engagement approach ensures informed decision-making, cooperation, and sustainable implementation of NBS in the Black Sea Region.

INVESTIGATING SOURCES AND CAUSES OF WATER QUALITY ISSUES

Pollution in the Black Sea is multifaceted, involving multiple streams in varying environmental parameters. Partial sewage treatment results in untreated sewage discharge into the Danube River basin. The Black Sea Region faces substantial anthropogenic pressures, notably in its northwestern shelf area, leading to eutrophication indicated by elevated chlorophyll-a concentrations. Pollution from coastal tourism compounds the problem, exacerbated by insufficient wastewater treatment and waste management. Notably, detectable bilge oil dumping, likely motivated by cost-cutting measures, adds to the pollution burden.

Traditional engineering solutions, while addressing certain problems, can create new challenges. Alterations to the Danube floodplain, such as draining wetlands or unmitigated sediment loading, have underscored the complex interplay between basin morphodynamics, hydrodynamics, and water quality regulation. The challenge of addressing diffuse pollution in the open sea is compounded by the potential bioaccumulation of persistent, toxic chemicals (PBTs) in the food chain, posing risks to both humans and wildlife. Nature-based Solutions (NBS) emerge as a comprehensive strategy for diverse objectives, safeguarding natural ecosystem functions. Effective mitigation requires a holistic approach encompassing sustainable practices, robust waste management, and ecosystem preservation to ensure the environmental integrity of these vital water bodies.

The primary approach to addressing pollution in the Black Sea is to target its sources upstream, emphasizing urban, peri-urban, and rural areas to prevent pollution from entering the sea. This is more effective and cost-efficient than costly in-sea clean-ups. Key considerations for developing pollution solutions include factors like efficacy, technical suitability, sustainability, compatibility, permitting, labor, energy, and integration with the landscape. Nature-based solutions (NBS) play a significant role and often involve public engagement due to their large scale. Successful NBS projects require local community support and sustained backing. NBS are designed for long-term operation, necessitating robust maintenance plans and clear governance. Tailoring solutions to specific problems optimizes effectiveness. A model illustrates how NBS simultaneously address effluent mitigation and yield co-benefits through ecosystem services, influencing livelihoods and well-being.

A substantial amount of pollution in the Black Sea Region enters through river systems, which serve various purposes like water supply, agriculture, transportation, energy, and waste disposal. Human activities often alter river dynamics through practices such as confinement, dam construction, and urban development. While engineering interventions can address local needs, they often create challenges elsewhere. Restoring natural systems, as seen in Seoul and Utrecht, can be more effective. In Europe, significant proportions of wetlands and floodplains have been converted to urban and agricultural areas, impacting biodiversity and flood mitigation.

The Danube River Basin, spanning 10 countries and 19 drainage areas, has undergone substantial alterations, resulting in the loss of wetlands and impaired flood management. Understanding connectivity is crucial for effective nature-based solutions. Connectivity involves interconnections within aquatic ecosystems, impacting movement of organisms, energy, and matter. Flow modifications, urbanization, infrastructure, and dams disrupt connectivity, limiting ecosystem services. Assessing fragmentation, regulation, sediment trapping, water consumption, urbanization, and road construction helps gauge river system connectivity. Re-establishing natural connectivity is vital for sustainable solutions in the BSR.

Globally, restoration efforts need to focus on revitalizing connections between river and wetland ecosystems. Key principles, as outlined by the US EPA, stress protecting aquatic resources, restoring ecosystem integrity and function, considering the original system's features (often using native species), addressing degradation sources, using passive restoration techniques or bioengineering, and consistent monitoring. These principles guide projects, including modifying riverbanks, reconnecting floodplains, and restoring wetlands as nature-based solutions for hydro-morphological improvements.

IDENTIFYING EFFECTIVE NBS TECHNIQUES

Artificial wetlands, known as constructed wetlands, mimic natural processes and are engineered for sewage, greywater, stormwater, or industrial wastewater treatment. They emulate natural wetland functions without discharging into ecosystems. Initially, they were primarily seen as tertiary treatment, following solids removal and other processes. However, they can also serve as source control, preventing contamination in water streams or reducing pollutants in sewers. Constructed wetlands have evolved with various types for water purification, mainly nutrient removal. These include surface and sub-surface types, with sub-surface ones being more effective due to better contact with sediment. Vertical flow wetlands enhance nitrogen removal. Different types can be combined for increased purification. Designing these systems involves purposeful manipulation for successful functioning and can take years to establish a mature root zone.

Coastal sediment holds vital environmental and geomorphological significance, accumulating mainly near estuaries, deltas, and coasts. However, human activities like dam construction, port development, and dredging have disrupted the natural sediment cycle, leading to imbalances in quantity and quality. Sediment management addresses flood risk, erosion control, and habitat preservation. Rivers' sediment sustains flow and habitat. Understanding sediment dynamics is crucial, as changes impact both natural and human systems. NBS strategies for sediment management include conserving beaches, promoting dune growth for barriers, and habitat enhancement. Innovations like sand borrowing and placement are also effective.

Harmful algal blooms pose significant concerns, particularly in the Black Sea. Algae blooms can result from excessive nutrients and cause ecological harm. Biodiversity loss due to human activities threatens marine life, with UNESCO warning of potential extinction for over half of marine species by 2100. Oceans regulate climate, house diverse species, and offer ecosystem services dependent on a healthy environment. Algae harvesting offers potential for renewable energy and food production. Efforts like the MERCES project aim to restore depleted European seas by reintroducing key species. Other nature-based solutions can counter biodiversity loss and improve water quality by utilizing algae for bioenergy and other applications.

THE FUNDING GAP AND APPROACHES TO FINANCING NBS

The urgent need for addressing climate change requires significant investments in Nature-based Solutions (NBS), yet recent studies reveal that NBS receive only 3% of global climate funding. Current annual allocations to NBS projects amount to around $133 billion, primarily from public financing, with a small portion dedicated to wastewater management. Private sector engagement is limited, focused on sustainable supply chains and environmental offsets. Challenges in NBS financing include uncertain cost estimations, lack of standardized revenue models, limited investor understanding, lack of regulations, and logistical difficulties. To overcome these challenges and mobilize funding and financing for NBS water security, key actors like philanthropic entities, donors/multi-donor funds, and Development Finance Institutions play essential roles. Blended finance approaches can combine public and private sources to address investment risks. Overall, increasing private sector involvement, standardizing revenue models, raising investor awareness, developing regulations, and establishing robust financing mechanisms are crucial steps for achieving effective funding and financing for NBS water security projects.

Effective funding approaches for Nature-Based Solutions (NBS) projects encompass diverse mechanisms and stakeholders. Germany's Emscher Project, the largest river restoration in Europe, secured financing through blended finance, earmarked public budgets, and subsidies, including €1.85 billion from EIB. Another case study focuses on the Blue Natural Capital Financing Facility (BNCFF), a social enterprise working with governments and Marine Protected Area (MPA) co-management entities, using blended finance to enhance revenue mechanisms for global MPAs, including the Turneffe Atoll of Belize. BNCFF structures facilities combining grants and debt to fund early-stage MPA investments, generating returns for investors from sustainable sources like eco-tourism fees and fisheries, ensuring financial sustainability. These examples highlight the diversity of potential funding mechanisms, involving international organizations, local governments, impact investment, and public-private collaborations, to advance NBS projects with environmental and financial benefits.

Measuring impact and conducting cost-benefit analyses for Nature-Based Solutions (NBS) projects are crucial for overcoming financial barriers, stimulating private sector engagement, and enhancing sustainability. Despite their potential to be up to five times more cost-effective than traditional grey infrastructure, comprehensive impact assessments and cost-benefit analyses are lacking in the Black Sea Region and beyond. Progress is evident with initiatives like the US federal Government's "A Roadmap for Climate Progress," which establishes a technical working group for cost-benefit analysis, aiming to integrate nature's value into financial records. The process involves scoping project benefits, quantification, validation, stakeholder engagement, and indicator alignment. Tools like the "Planetary Computer" and "ESII Tool" aid data collection, decision-making, and benefit assessment. Valuation of benefits requires data across timeframes and organizations like Denkstatt and EcoMetrics contribute to quantification efforts.

GOVERNANCE AND POLICY

The potential framework for NBS governance in the BSR emphasizes existing integrated governance mechanisms for wastewater management and implementation guided by relevant agencies. Collaborative governance principles involving co-creation and multi-stakeholder engagement are crucial. The governance model varies based on local needs, with distinct roles for state agencies at different levels (strategic, operational, tactical, and reflexive) to formulate strategies, secure financing, and exchange knowledge for successful NBS implementation. Multi-level governance involves vertical and horizontal collaboration, along with non-state actors and communities. Transparent and accountable governance empowers stakeholders through knowledge sharing and capacity enhancement, aiming for effective NBS implementation within the Black Sea Region.

The policy landscape for Nature-based Solutions (NBS) in the Black Sea Region involves complex governance mechanisms to address pollution challenges, necessitating harmonization and clarity. EU policies have influenced the region, but challenges remain, including limited technical capabilities and conflicting roles in enforcing environmental regulations. While green infrastructure and NBS align with global and EU policy frameworks, these concepts are not fully integrated into national strategies of Black Sea countries. The EU Water Framework Directive supports NBS approaches for ecological water status, and the Common Agricultural Policy includes environmental investments. Moldova stands out for its NBS integration into policies emphasizing water use, biodiversity, wetland restoration, and disaster risk reduction. The US Federal Government's NBS roadmap sets a comprehensive strategy for scaling up NBS to combat climate change and address nature loss. Local context and quantitative targets play a vital role in NBS effectiveness, highlighting the need for inclusive and measurable strategies.

Land-based sources (LBS) are responsible for over 80% of marine pollution globally and in the Black Sea, primarily due to agricultural runoff and wastewater discharges. The policy overview highlights the need for transboundary cooperation in protecting the Black Sea from LBS pollution, focusing on conservation, eutrophication reduction, biodiversity habitats, and water quality improvement. Implementing measures like wastewater treatment plants and solid waste management facilities is crucial, even though it may be expensive. International governance focuses on action-oriented obligations rather than specific standards, emphasizing national implementation and enforcement of relevant frameworks.

CASE STUDIES

Riparian restoration in the Black Sea Region focuses on wetland revitalization and improved river-wetland connectivity in the Danube River basin. One such project in Romania aimed to enhance water inundation in Gârla Mare and Vrata marshlands by modifying water channels, flood storage, and dykes to preserve habitats and protect fish ponds. In Moldova, a French Vertical-Flow Treatment Wetland was constructed for wastewater treatment, utilizing a two-stage process and biomass harvesting for potential biogas production. These case studies underscore the multifaceted benefits of NBS, from environmental restoration and biodiversity conservation to sustainable wastewater treatment and resource utilization, emphasizing the importance of leveraging nature's potential for holistic socio-economic and ecological gains in riverine ecosystems of the Black Sea Region.

One example of NBS applied to coastal protection and rehabilitation is on the southern Romanian Black Sea shore. This coastline of approximately 240 km faces erosion issues due to port construction, dam development, and deteriorated coastal infrastructure. Erosion, sediment transport disruption, and pollution have impacted water circulation, habitats, and biodiversity. The NBS project aims to restore the coastal zone by creating new beach areas, managing sediment, and enhancing ecosystem services. Co-financed by the European Investment Bank and the EU, the initiative involves constructing and rehabilitating coastal structures, spanning over 30 kilometers and 17,200 hectares of wetlands. Measures include groynes, breakwaters, revetments, cliff protection, and artificial reefs to safeguard marine habitats and beaches. An integrated coastal monitoring program will also be established to support conservation efforts and beach maintenance.

Nature-based solutions in the open ocean involve harnessing natural processes to address environmental challenges, enhance ecosystem health, and promote sustainability in vast marine environments. Microbial-based strategies for oil spill cleanup, including bioaugmentation and biostimulation, offer effective and sustainable alternatives, as demonstrated by the BP oil spill response and the study of A. borkumensis bacterium. Algal processing presents versatile opportunities, from bioplastics to aquaculture, with harvesting techniques like mechanical and chemical methods, as well as bioreactors, showcasing potential for sustainable high-value product production. The Ocean Cleanup employs a nature-inspired approach by strategically harnessing ocean forces to collect debris before entering oceans, albeit with limitations against chemical and biological pollutants. Collectively, these case studies underscore the multifaceted applications and benefits of NBS, spanning wetland creation, microbial remediation, algal utilization, and ocean debris mitigation, contributing to holistic environmental sustainability.

RECOMMENDATIONS

To support the development of Nature-Based Solutions projects for effective water quality improvement in the Black Sea and beyond, several recommendations emerge: