Table 2. Results for the three main scenarios.


Source of Nitrogen Reference Scenario “Most Likely” Scenario “Pipeline” Scenario
Himmerfjärden Sewage Treatment Plant, effluent nitrogen concentration 10 mg/L 4 mg/L 4 mg/L plus offshore outfall
Agriculture No additional measures Wetland creation (25 ha) Wetland creation (25 ha)
Private sewers connected to sewage treatment plant 0% (no additional measures) 25% 25%
Mean summer Secchi depth 3.1 m 3.7 m 4.1 m
Secchi depth change - 0.6 m 1 m
Benefits of Secchi depth improvement (summed present values) - 309 MSEK 516 MSEK
Costs of scenario (summed present costs) - 133 MSEK 539 MSEK
Net benefit - 176 MSEK - 23 MSEK