Survey targets peatlands that could improve Helsinki’s drinking water

A survey is identifying drained peatlands that place the greatest strain on Lake Päijänne and waterways around Pihtipudas, with restoration potentially improving the quality of drinking water supplied to Helsinki, Yle reports.

Hiilipörssi, a company that provides compensation and peatland restoration services, is carrying out the assessment as part of a water management project launched this year and scheduled to run until 2028.

Large areas of Finnish peatland have been drained to produce timber for the forest industry. Water flowing from drained areas can increase nutrient levels and sediment in downstream lakes. Research indicates that emissions of carbon and nutrients from old drainage areas can grow over time.

Jaakko Junikka, Hiilipörssi’s waterway specialist, said the effects extend beyond water becoming darker. He said heavy metal concentrations can rise alongside the darkening, with metals entering fish and, in turn, the human body.

The assessment will identify drainage areas where restoration could most effectively improve downstream water quality. Hiilipörssi plans to publish an open list of the worst areas. The company hopes the information will encourage landowners to restore their peatlands. It pays landowners for restoration, and they can also earn money from timber removed from the peatland.

The most damaging drainage areas around Pihtipudas have already been identified, and the survey will next turn to Päijänne. The largest source of pollution is the Häyhtiönjärvi area, including the drained peatlands Honkaneva and Häyhtiönneva. Water from these areas flows into Lake Alvajärvi. The Lahnalampi area, which drains directly into Lake Muurasjärvi, is the municipality’s second-largest source of strain on waterways.

Helsinki gets its drinking water from Päijänne. Junikka said the cost of treating drinking water for the capital region has risen as the lake’s water has darkened. He said it could be economically worthwhile to clean the water at its source rather than at a treatment plant in Helsinki.

The project, which is partly funded by the Ministry of the Environment, also includes restoring two peatland areas. The sites will be selected based on the survey, with the aim of restoring those that place the greatest strain on waterways.