Participatory CBA for water quality, Helge River catchment, Sweden

• The Helge River catchment is in southern Sweden (Skåne and Kronoberg counties). It is part of the Baltic Sea drainage basin, representing 0.39% of rivers' water inflow. 
• It is dominated by forestry land use.
• It contains Kristianstad Vattenrike UNESCO Biosphere Reserve with regional, national and international biological values. 
• Water colouration is identified as the dominant environmental pressure affecting multiple stakeholders.

To apply bottom-up Cost-Benefit Analysis for water quality improvement, enabling local stakeholders to identify environmental pressures, suggest management strategies, and assess costs and benefits from their perspectives.

Challenges addressed

Both strategies address environmental management, with water pollution as the central challenge. By starting from problems identified by local people, the approach also builds local support for the measures.

Costs of NbS

Local stakeholders in the 4,725 km² Helge River catchment developed two strategies to improve water quality over 2021–2030. The River strategy creates stormwater ponds, floodplains, wetlands, riparian zones and 83 km of re-meandered river, at a present-value cost of about EUR 29 million. The Forest strategy restores 35,000 ha of wet forest, converts conifer stands to broadleaves, creates riparian zones and removes fish migration barriers, at about EUR 167 million (2023 prices, 3.5% discount rate).

Potential impacts/benefits

Both strategies improve surface and groundwater quality, reduce the brown colouring of the river and preserve habitats for wildlife. Cleaner water and richer nature also boost recreation and tourism in the catchment. The River strategy’s floodplains and wetlands help regulate river floods, while the Forest strategy additionally reduces flood risk and controls erosion and sediment. The River strategy’s benefits are worth about EUR 226 million, over half of it from reduced water colouring, and the Forest strategy’s about EUR 294 million (present value 2021–2030, 2023 prices).

Benefit–cost ratio

Both strategies pay off for society. The River strategy reaches a BCR of 7.75 and the Forest strategy a BCR of 1.76. The lower-cost River strategy therefore gives the highest return per euro invested.

• Stakeholder workshops to identify pressures and propose strategies. 
• Expert elicitation to assess ecosystem service impacts. 
• Benefit transfer using income-adjusted values from Baltic Sea region studies. 
• Dynamic spreadsheet-based CBA template allowing real-time assumption adjustments during meetings. 
• Qualitative expert ratings of impacts on biodiversity, flood risk, erosion control, recreation and water quality.

J.F. Carolus et al. (MIRACLE project)

Study overview

The Helge River catchment in southern Sweden implemented a participatory environmental planning process using a bottom-up Cost-Benefit Analysis (CBA) approach to address water quality issues. Unlike conventional top-down CBA where central authorities define policy options, this process began with local stakeholders identifying environmental pressures and proposing strategies to improve ecosystem services.

The Helge River catchment serves as the system boundary, with stakeholder groups including agricultural producers, forestry sector representatives, hydropower operators, and public sector institutions. Three primary strategies were developed: "River" (restoring aquatic ecosystems through stormwater ponds, flood plains, and wetlands), "Forest" (sustainable water management in forestry through wet forest restoration and riparian zones), and baseline measures under existing CAP and Water Framework Directive programmes.

The analysis covered the period 2017–2030 with a social discount rate of 3.5% following Swedish national guidelines. Results showed substantial variations in benefit-to-cost ratios across strategies. The "River" strategy achieved a BCR of 7.75 with net present value of SEK 2,212.95 million, while the "Forest" strategy had a BCR of 1.76 with NPV of SEK 1,428.59 million. The baseline scenario yielded negative returns with BCR of 0.31.

Key benefits included biodiversity preservation, flood risk reduction, recreation and tourism value, and improved surface and groundwater quality. Reduced water colouration was valued at SEK 1,323.73 million across strategies. Nutrient mitigation achieved 88,089 kg/year nitrogen reduction and 5,563 kg/year phosphorus reduction under Strategy 1.

The bottom-up approach revealed important distributional effects. In Strategy 1, the agricultural sector bore SEK 256.28 million in costs, while Strategy 2 placed SEK 1,754.58 million costs on forestry. This highlights how positive social returns may coexist with unequal burden-sharing among stakeholder groups.

The study demonstrates that participatory CBA can integrate local knowledge, increase stakeholder acceptance, and inform compensation mechanisms when private costs exceed private benefits despite positive social NPV.