Halistenkoski, Turku Finland
Posted by: 
kuja1a
N 60° 27.885 E 022° 18.379
34V E 571835 N 6703883
Halistenkoski is the eleventh rapid of the Aura River and the lowest rapids in Turku, on the border of Haliste and Nummi districts
Waymark Code: WM136TE
Location: Finland
Date Posted: 09/29/2020
Views: 27
The Halistenkoski region has been inhabited since the Iron Age and its flow has been utilized at least since the Middle Ages: the first mention of the mill on the site dates back to 1352. Later, Finland's first Verkatehdas, flour mills and wadding mill were used in the 16th century. The Turku Waterworks has been located near Halistenkoski since 1923.
The fish ladder was built in 1995 and renovated in 2002 to improve the rise of leatherback. It consists of 22 vertical pools with a depth of about 1.5 m. The fall height of the entire staircase is 5.5 meters and the top basin has a fish catcher that allows you to track species, number and weight. The most common species found in the fishway are sea trout, sea salmon and rainbow trout. However, the number of fish entering the fish ladder depends on the annual amount of water in the Aura River. In the peak year of 1998, about 370 salmon fish rose through the fish ladder, while when the water was low in 2003, only thirty salmon fish rose.
The River Aurajoki Information Centre is located in an old miller's house at Halistenkoski. Information is available on the River Aura and its sights, as well as on canoe trips and fishing. Aurajoki fishing permits and canoe rentals are available.
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Turku waterworks has been located near the rapids since 1923, and the rapids was dammed for raw water need. Luckily we don't use this muddy water for raw water need anymore.
Nowdays the water flowing from your tap comes from the Kokemäenjoki river. From the river, the water is pumped into the pre-treatment plant of Turun Seudun Vesi Oy, where all solid matter, such as clay, is removed from the water. This process also removes 99% of all pathogens. The murky river water is transformed, and as it leaves the plant, it is clear. From there, it starts a 30-kilometre trip towards the Virttaankangas ridge.
The pre-treated water from Kokemäenjoki ends up in the ridge through a total of 19 recharge basins, whose combined surface area is 2.4 hectares. The water flows within the ridge for an average of three months. The soil in Virttaankangas not only cleans the water, but also optimises the pH value and hardness of the water in a completely natural manner. The next time that the water absorbed into the soil sees the light of day is when you open your tap.
The water flows through the ridge like groundwater, and it is pumped up using groundwater wells, which only need to be drilled down approximately 40 metres, not until the bottom of the fracture in the bedrock. The location of the wells is more essential: two wells may be located only 70 metres apart, but one may produce three times the water the other one does, because of its location. The best wells can produce 12–13 million litres of water every day.
From the wells, the water is pumped into a filtered water reservoir, from where it starts its journey towards Turku after three months inside the ridge. The water flows the entire 60 kilometres to the Turku region using gravity. Virttaankangas produces over 62 million litres of artificial groundwater every day, which is enough to provide 300,000 people with domestic water. All of the water flows to the Turku region through pipelines every day.
Waterway where the dam is located: Aura River
Main use of the Water Dam: Water Supply (Drinkable)
Material used in the structure: Concrete
Height of Dam: 7
Date built: 04/01/1923
Fishing Allowed: yes
Motor Sports Allowed: no
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Visit Instructions:
Photo of the Dam and a description of your visit.