The Lapväärtin-Isojoki watershed originates from the springs and streams of Lauhanvuori National Park. The valuable river basin district has been been under restoration through the Freshabit LIFE IP project, and a strategic plan, a water vision, is being drawn up for the watershed.
The Lapväärtin-Isojoki watershed is located in the provinces of Southern Ostrobothnia, Ostrobothnia and Satakunta, and the river flows in the area of six municipalities: Kauhajoki, Isojoki, Karijoki, Kristiinankaupunki, Teuva and Siikainen. A small part of the watershed is also located in the area of the city of Kankaanpää (Honkajoki). The watershed covers an area of 1,098 km2 and belongs to the Kokemäki-Archipelago Sea – Bothnian Sea water management area.
The Lapväärtin-Isojoki watershed originates from the springs and streams of Lauhanvuori National Park and flows into the Bothnian Sea south of Kristiinankaupunki. The estuary consists of several small islands and the water bodies and canals between them.
The main river basin and the main tributaries comprise seven parts: Isojoki, Pajuluoma (in the photo), Heikkilänjoki, Karijoki, Metsäjoki, the lower part of the Lapväärtinjoki and Kärjenjoki. The part above the main river is called the Isojoki River and the lower part is called Lapväärtinjoki. The Lapväärtin-Isojoki river changes its nature from narrow natural headwaters to meandering river estuaries and a wide estuary. The largest tributary of the Kärjenjoki is called Siiroonjoki at upper reaches and Lillå at downstream. The length of the main river is 75 km and the total length of the most significant tributaries is about 115 km. In addition, the water body includes a large number of small streams. The percentage of lakes in the watershed area is only 0.2 %, the largest lakes are Haapajärvi (52 ha) and Kangasjärvi (47 ha).
Lapväärtin-Isojoki is a very important watershed due to its natural state, fisheries and biodiversity. The most important natural values of the river valley are related to both the habitat and the species. The most valuable habitats are the natural river route, including natural streams and rapids, significant old natural forests along the river bank, and provincially valuable bogs. Based on their endangerment, the most valuable species are the pearl mussel and the sea trout. From the point of view of conservation value, threats in the area include erosion, flooding, embankment, drainage, dredging, surface water pollution, water dam, immigrant species and climate change.
The Freshabit LIFE IP project aims to improve the condition and diversity of Natura 2000 river basins. The large-scale nature conservation project will restore inland waters, rivers and streams and improve the living conditions and environments of hundreds of species. Freshabit Life IP – Ostrobothnia’s rivers sub-project includes the Lapväärtin-Isojoki, Karvianjoki and Lapväärtin-Isojoki upper reaches and the Ähtäväjoki river.
During the project, several restoration and water and species protection measures have been implemented in Lapväärtin-Isojoki. The project has, for example, rehabilitated streams, revitalized declining river mussel stocks, built fishing routes, wetlands, surface drainage fields and various water protection structures to reduce the load on water bodies.
The project is scheduled for 2016–2022 and is coordinated by Metsähallitus Parks & Wildlife Finland. The project has received funding from the EU’s LIFE program. In the Ostrobothnia region, the actors are the Southern Ostrobothnia Centre for Economic Development, Transport and the Environment, Metsähallitus, the Finnish Forest Centre, the Finnish Environment Institute, the University of Oulu, the Natural Resources Institute Finland and the Finnish Association for Nature Conservation in Ostrobothnia.
A water vision for the Lapväärtin-Isojoki watershed will be developed in extensive co-operation with the support of the Freshabit LIFE IP project. The purpose of the water vision is to bring together the inhabitants of the area and the actors in various fields and to draw up a vision for the use and condition of the water system that extends into the future. The water vision has common objectives and measures aimed at coordinating, among other things, flood risk management, the use of water resources, water management, the protection of biodiversity and fisheries on the Lapväärtin-Isojoki river. In addition, efforts will be made to create regional commitment to activities and to raise awareness of water-related issues, taking into account the region’s nature tourism and business activities.
The Southern Ostrobothnia Centre for Economic Development, Transport and the Environment, the Lapväärtin-Isojoki River Basin Planning Working Group and a wide range of local stakeholders, for example from the economy, are involved in the implementation of the water vision. The water vision has been created in joint workshops, and a nature photo competition and library exhibition have also been organized. Water Vision has also hidden geocaches in the watershed.
More information about the water vision can be found on the vesivatten.org website. You can also check out the Story Map of the Lapväärtin-Isojoki water vision (ArcGIS Online), which presents the Lapväärtin-Isojoki watershed and its drainage basin plan as geographic information or images.
Text and river images of the article: Katja Vainionpää
Salmon photo: Matti Saarikoski
Main picture (from the roots of Siiroonjoki): Terttu Hermansson
Suvi Hämäläinen from the Southern Ostrobothnia Centre for Economic Development, Transport and the Environment tells that in the autumn of 2021, the EU-funded LIFE Revives project has started in the area, where habitats for freshwater pearl mussels are being rehabilitated and farmed mussels are returned to the river. This project will revitalize freshwater pearl mussel stocks in three countries (Finland, Sweden and Estonia) and will run until 2027. The University of Jyväskylä coordinates the project, and other Finnish partners are Metsähallitus Parks & Wildlife Finland, Metsähallitus Forestry Ltd and the Centres for Economic Development, Transport and the Environment of Southern Ostrobothnia, Pirkanmaa and Southwest Finland.