Restoration and monitoring of Vantaa River, Finland
Solution to which problem
Awareness raising of water management and related issues among local citizens, poor stormwater management, restoration of salmonid fish population in river, sewage issues from scattered settlements
Technical conditions
- Several brooks at Vantaa are important for sea trout reproduction. Vantaanjoki River and its brooks have become the most important watercourse for the vulnerable sea trout population of the Gulf of Finland. It has also a population Atlantic salmon of the Baltic Sea. Action plan for restoration of brooks was compiled during 2016. Restoration includes improvement of culverts, surrounding areas, recreational values and actions to improve water quality and flow control, for example. River and creek sides are popular areas for citizens’ outdoor activities
- Biofiltration facilities are being built to improve the quality of street runoff waters (2 pilot sites): storm water is led into depressions with vegetation where water filtrates through soil layers into drainage and finally into brooks.
- River Vantaa’s Tikkurilankoski dam is planned to be partly removed to restore the rapid and to allow fish passage. City is reconstructing Tikkurila rapids at city center to improve mitigation of sea trout and salmon and to increase the area of habitats for their reproduction. Also several other species of fish benefit from the measures.
- Water quality is regularly measured at river Vantaa and 6 tributary brooks.
- Information on sediments, benthos, fisheries etc. is collected to help planning measures to improve brook state and water quality.
- River Vantaa’s Tikkurilankoski dam is planned to be partly removed to restore the rapid and to allow fish passage. City is reconstructing Tikkurila rapids at city center to improve mitigation of sea trout and salmon and to increase the area of habitats for their reproduction. Also several other species of fish benefit from the measures.
Implementation
Nature trips to streams and brooks help local citizens to understand better the value of surrounding waters and increas citizens' respect for stream nature. For this purpose, during 2015-2016 City of Vantaa administration organised the theme year of streams and brooks. In the framework of the theme year various activities for river and streams restoration had been organized, e.g. gravel beds for spawning were built for trout and Impatiens glandulifera was uprooted from riverbanks in order to fight the invasive species and end erosion. The city organised nature trips and during autumn special trips for observing spawning trout.
Result
Improved storm water management:
- Storm water management is established as part of planning and construction processes.
- Flood risk and erosion are diminished. Practices to improve storm water quality are improving resulting in improved water quality at brooks, rivers and the Baltic Sea.
River and brook restoration:
- The uprooting of Impatiens glandulifera around the Vantaa River and its subsidiaries has been very effective. Its growth has been curbed and the indigenous plant species have been able to spread back to their old habitats.
- The uprooting of Impatiens glandulifera helped trout, as there is less erosion of the banks after the deep-rooted and perennial indigenous plant species spread back to the stream banks.
- The gravel beds enhance trout spawning possibilities in the streams and brooks of the river Vantaa.
Raised awareness:
- Locals have more knowledge of the environment and water nature resulting into better solutions when constructing,
- Active citizens take care of their environment and nature conservation along brooks and rivers.
- Several small measures result in less erosion, improved water quality and improved conditions for migratory fish and recreational values of the brooks and rivers.