Adapting flood risk and river basin management to climate change in Kalajoki river basin, Finland

The Kalajoki river basin, situated in Finland, has an annual average precipitation around 560 mm, 200 mm of which is snow. Kalajoki is a mid-size lowland river, total length 130 km and drop 113 m. The land use in Kalajoki river basin is about 80% of woodland and peat land, and 15% agriculture. The settlements are situated along the main river channel. Due to the low number of lakes, the river basin is characterized by large intra-seasonal variations in discharge, resulting in frequent floods and low discharge in dry periods. Ditching and dredging projects in the river basin have fastened the runoff. In addition, flood protection measures, mainly flood embankments, have reduced the natural flood plains.

This report identifies possibilities to achieve “climate proof” flood risk management plans and river basin management plans. The regional water management authority is responsible for the plans. The BASE project supported ongoing planning processes and integration of climate change adaptation measures (such as lake regulation, floodplains, permanent flood protection structures) into the plans. Alternative management choices and their impacts on the river basin were compared. A questionnaire for citizens about flood risk perceptions and acceptability of measures and two stakeholder workshops were organized to support the evaluation of measures and stakeholder participation. For the river basin management plan, climate change impacts on agricultural loading to river and evaluation of cost-effectiveness of the measures to reduce loading were conducted.