Water Act (No. 587 of 2011).

The Finnish Water Act is a comprehensive statute governing the use, management, and protection of water resources and aquatic environments. The law’s primary objective is to ensure that the use of water resources is socially, economically, and ecologically sustainable, while preventing and reducing harm caused by water use and improving the condition of water bodies and aquatic ecosystems. It regulates a wide range of water management activities (“vesitalousasiat”), including projects and actions that affect surface water, groundwater, and aquatic environments. The Act also clarifies its relationship with other legislation, stating that matters related to pollution prevention, water supply, dam safety, health protection, land use planning, and nature conservation are governed by separate laws such as the Environmental Protection Act, the Water Services Act, the Dam Safety Act, and the Nature Conservation Act.
The Act establishes a detailed framework of definitions and concepts to guide its implementation. It defines key terms such as water body, river, stream, groundwater, groundwater deposit, water management project, hydropower, waterway, and dredged material. A water management project includes any activity or structure carried out on land or water that may affect water systems, water environments, groundwater conditions, or the use of water areas. The law distinguishes between various types of watercourses (rivers, streams, minor channels) based on characteristics such as drainage area and water flow, and it clarifies what constitutes a water area boundary, typically defined by the shoreline at the mean water level. The Act also extends its application beyond inland waters to include Finland’s territorial waters and exclusive economic zone, ensuring that marine water resources are governed by similar principles.
Another central component of the Act is the regulation of water infrastructure and navigation routes. It recognizes the importance of maintaining waterways for water flow, navigation, timber floating, and fish migration, establishing the concept of a main channel (valtaväylä) within rivers and certain narrow waterways. These provisions ensure that human activities—such as construction, dredging, hydropower development, or navigation infrastructure—do not obstruct natural water flow or ecological functions. The Act also addresses special-use areas (such as ports, swimming areas, or waterfront properties) and distinguishes between public and private waterways, setting out the legal framework governing their use and maintenance.
Overall, the Finnish Water Act functions as the central legal instrument coordinating water resource governance in Finland. It integrates environmental protection with economic uses of water—such as hydropower production, transportation, and land development—while safeguarding ecological integrity and public interests. By defining legal responsibilities for project developers, establishing regulatory oversight, and linking water governance with broader environmental and planning legislation, the Act creates a comprehensive legal system for sustainable water management, balancing competing uses of water resources with the protection of aquatic ecosystems and public welfare.