Ewa Leś, Andrea Cervantes & Gunnar Norèn: Source to see approach to ensure the GES of the Baltic Sea

One of the significant conclusions across the Baltic Sea Region (BSR) is that the existing model of water resources management does not fully provide a solution to the water problems we experience nowadays. Exemplary major challenges among BSR countries include water pollution and eutrophication, hydromorphological pressure, and – of course – funding for river restoration. The restoration of natural retention is seen as a remedy for current water management problems.

One of the major problems for surface water in the Baltic Sea Region countries is eutrophication caused by diffuse pollution of nitrogen and phosphorus from agriculture, because of constant on-going overfertilization when Economic Optimal Fertilization is applied. Much has been done to reduce the load of nutrients from agriculture, but still, the measures are voluntary. Among the measures proposed to fulfil the WFD and the Baltic Sea Action Plan (BSAP), are also various restoration methods in the landscape. To prevent eutrophication, land-based measures in agricultural areas, such as buffer strips, sedimentation ponds and re-wetted and constructed wetlands are essential, with priority in lower river basins with high nutrient water concentrations. More important, besides End-of-pipe solutions, are mandatory measures to minimize overfertilization via yearly calculation of nutrient surplus on each field. Restoration to counteract nutrient leakage from agricultural areas is not to be forgotten – not only to mitigate eutrophication, but also to act as a carbon sink and promote biodiversity.

Hydromorphology pressures, such as river barriers, enhance eutrophication processes by slowing down the natural free-flow of water and reducing self-purification abilities.

Under the Nature Restoration Regulation, EU Member States are required to implement restoration and habitat re-establishment measures gradually. These measures shall cover at least 20% of land and sea areas in the EU by 2030, and all ecosystems in need of restoration by 2050 (Art.1(2)). It also requires MS to assist in restoring at least 25 000 km of free-flowing rivers by 2030 (Art. 9).

In terms of NRR implementation, firm monitoring practices must be implemented to follow the state of both passive and active restoration areas, considering climate change, eutrophication, pollution, and other anthropogenic stressors. These practices strengthen climate adaptation and help in choosing the right restoration tools for the area of restoration.

Below, the crucial active measures related to the freshwater ecosystems are presented, including those related to eutrophication.

Exemplary active restoration measures:

• For longitudinal continuity, total dam removal should be a priority. Focus on constructed natural bypasses and install fishways only if dams cannot be removed.

• Establish a requirement of a minimum annual flow so all aquatic species can survive and a slope angle of 2 degrees so all kinds of river fauna can migrate up and down streams, in bypasses/fishways.

• Restore also lateral connectivity and improve the natural functions of the floodplains, i.e. remove artificial embankments, and restore floodplains.

• Ensure natural buffer zones along the entire river and tributary length and, for water bodies of at least 10-20 m, for 80% of the river length to reduce eutrophication pressure and to support biodiversity.

• Reduce input of nutrients from livestock and farming (e.g. by promoting organic farming, improving soil stability) and via mandatory measures for minimization of nutrient surplus with fertilization practices (which can be seen as a passive measure) which would reduce water column nutrient concentrations.

By the 1st September 2026, Member States shall submit Nature Restoration Plans (NRP) for their territories, including exclusive economic zones (EEZ), indicating how NRR targets will be implemented and achieved. Moreover, measures in place must deliver actual source-to-sea restoration of all riverine, coastal, and marine ecosystems in the Baltic Sea catchment area.

Conclusion: CCB has prepared guiding recommendations for the development of NRPs, the achievement of restoration targets and, ultimately, GES in the Baltic Sea catchment area. As well as elaborated a list of tailored ecosystem-specific recommendations for riverine, coastal, and marine restoration (active and passive), to contribute to the importance of the land-to- sea connection. To achieve the goals of the NRR in the Baltic Sea, it is essential to establish a common regional understanding and develop clear guidelines.

Sources:

• https://www.ccb.se/publication/Guiding-Recommendations-for-Source-to-Sea-Restoration-2025
• https://www.ccb.se/publication/greatest-water-management-challenges-baltic-sea-region
• https://www.ccb.se/publication/2021-river-barriers-to-remove-or-mitigate-in-the-baltic-sea-region