The Vantaanjoki river basin flows through the Helsinki metropolitan area, where there are about 1 million inhabitants, before discharging into the Baltic Sea. Purified sewage waters from this region are discharged into the open sea area in the Gulf of Finland. However, in the upper reaches of the river there are two towns (Riihimäki and Hyvinkää) with their own wastewater treatment plants also discharging purified wastewaters into the river.
The length of the main channel is 101 km.
The total length of all rivers in the Vantaanjoki river basin is approximately 300 km.
Medium flow at the river mouth is 16 m3/s, but only 2 m3/s in low water conditions.
Residence time from Riihimäki to the river mouth is on average 11 days.
The catchment area is 1685 km2.
About 1 100 000 citizens in 14 different municipalities live in the vicinity of the river.
Water pH is ca 7.3.
Vantaanjoki water was used as the drinking water for Finland’s capital Helsinki and its metropolitan area until 1982, when Päijänne tunnel was introduced.
River water is still used as drinking water during the maintenance of the Päijänne tunnel.
“The river is a friend to us all!”
Did you know that over one million people live in the Vantaa River area?
The Vantaa River runs over 100 km from Riihimäki to Helsinki, where it discharges into the Gulf of Finland at the Old Town Bay (Vanhankaupunginlahti). There is a 100-meter drop on the entire journey. The riverbanks have urban sceneries, but mostly the river flows in beautiful and lush grove landscape.
Vantaanjoki gives the opportunity for many hobbies. Along the way, nature is versatile in terms of both flora and fauna. Above all, the Vantaa River is a fantastic fishing spot!
It is a salmon river, where sea trout and sea salmon rise for spawning. There are many well-groomed fishing destinations in Vantaanjoki. Indeed, it can be said that Vantaanjoki is the most important recreational fishing destination in Southern Finland. There are more than 300 kilometers of river channel in the Vantaa river basin. In the river there are 24 fish species from bleak (Alburnus alburnus) to river lamprey (Lampetra fluviatilis).
There is a total of 45 known rapids in the Vantaa River, some of which have been almost or completely destroyed in connection with e.g. river clearings for log floating. Each rapid has its own, interesting history.
The refurbishment of stream-water fisheries has been practiced in earnest for just over 10 years in Finland. Thus, we are still quite young at this work. However, a historic step took place at the mouth of the river Vantaanjoki in 1986 when the Old Town fish ladder was completed. This was, in fact, the first large, reliably working fish ladder in the country.
Why is it an important case study for BONUS RETURN?
Apart from the fact that over one million people live in the Vantaanjoki catchment and its immediate vicinity, it has tremendous recreational value while at the same time being the 2nd largest polluter of the Gulf of Finland in the Finnish rivers.
There are exceptionally lot of high-quality initial data available making it a good case study, including automatic monitoring station at Pitkäkoski. It is also close to one of BONUS RETURN’s partners, SYKE who have developed relationships with a variety of local partners and stakeholders in the area.
Problems in Vantaanjoki River
The Vantaanjoki River Basin is characterized by a variety of water resource problems like the non-point source pollution from agricultural fields and scattered settlements, as well as the point-source pollution coupled with storm-water runoff from the urban areas.
BONUS RETURN aims to solve problems of high nutrient loading from agricultural and urban areas and occasional emissions, or overflows, from Waste water treatment plants. The project also aims to provide better recycling of sludge from Waste water treatment plants and other organic side-streams as fertilisers, as well as other products of circular economy.
So far, initial data for the Soil and Water Assessment Tool (SWAT) model application of the Vantaanjoki catchment has been collected and input provided, and the parameterization, calibration and validation of the model application has been done. Meetings with key informants and a workshop with stakeholders are ongoing.
Main objective for a healthier Vantaanjoki river
The ultimate goal in the BONUS RETURN project is to reach the river Vantaanjoki with such a good ecological status that the following visions will be realised:
Healthy riversides – no direct surface runoff into the river, protective shorelines, which are important also for recreational use.
The water is so clean that the trout will thrive in the river.
Small tributaries and lakes are taken into account, and not just the load transported into the Baltic Sea.
All waterbodies, as well as tributaries like the Palojoki River, may serve a recreational purpose.
Provide development needs e.g. in the management of alien species.
The Hyvinkää wastewater treatment plant is efficient such that the transfer of sewage pipelines from the sparsely populated areas to the treatment plant should be increased.
BONUS RETURN aims to contribute to a cleaner Baltic Sea by achieving the above-mentioned goals. The project brings new innovative solutions to the attention of the region’s stakeholders. Undoubtedly, all goals will not be realised immediately, but actionable steps towards achieving these goals are at the core of the project’s objectives.
SWAT modelling and new eco-techniques allow us to evaluate different future visions that will help the region to find the best solutions to improve the ecological status of the Vantaanjoki river.
Written by Jari Koskiaho and Brenda Ochola