Bällstaån
Encyclopedia
Bällstaån or Spångaån is a small stream
Stream
A stream is a body of water with a current, confined within a bed and stream banks. Depending on its locale or certain characteristics, a stream may be referred to as a branch, brook, beck, burn, creek, "crick", gill , kill, lick, rill, river, syke, bayou, rivulet, streamage, wash, run or...

 in northern Stockholm
Stockholm
Stockholm is the capital and the largest city of Sweden and constitutes the most populated urban area in Scandinavia. Stockholm is the most populous city in Sweden, with a population of 851,155 in the municipality , 1.37 million in the urban area , and around 2.1 million in the metropolitan area...

. Flowing through the municipalities of Järfälla, Stockholm, Sundbyberg, and Solna
Solna Municipality
Solna Municipality is a municipality in Stockholm County in east central Sweden, located just north of the capital Stockholm. Its seat is located in the 'city' of Solna....

, it empties in the bay Bällstaviken, the innermost part of Ulvsundasjön.

Some 1,4 km of the stream is passing through culverts and long stretches of it have been straitened out to form part of the local stormwater system. Notwithstanding, other sections are furnished with promenades and ponds and therefore considered as of local recreational interest. The municipalities sharing the catchment area, together with the county administrative board, are collaborating to improve water quality and the areas surrounding the stream.

Catchment area

Flowing from Viksjö
Viksjö
Viksjö is a district of Järfälla Municipality, Stockholm County, Sweden, in the Stockholm urban area.Viksjö has 15,000 inhabitants. The district was developed in the 1970s. The architecture consists mainly of detached terraced houses....

 in Järfälla, the stream starts as a ditch receiving considerable amounts of stormwater from the residential area Jakobsberg
Jakobsberg
Jakobsberg is a suburban area within Stockholm urban area, and the seat of Järfälla Municipality, Stockholm County in Sweden.Jakobsberg, Järfälla's commercial and administrative centre, grew up around the railway. In the 1940s, blocks of flats were built and the municipal council moved its offices...

. After a bit more than 2 km, near Barkarby Airport
Barkarby Airport
Barkarby Airport was a disbanded Swedish Air Force base, near Akalla north of Stockholm used for general aviation. Barkarby Airport was one of Sweden’s oldest active airports until it was closed in 2010. A large shopping complex is still situated close to – and partly on – the airfield. Current...

, it dives into a short culvert before merging with another ditch (Veddsta dike) bringing water from a golf range, industrial and residential areas. It then passes under the traffic route E18
E18
E18 or E-18 may be:* E18 error, a Canon digital camera error code* County Route E18 , a County route in California* DRG Class E 18, a class of German electric locomotives* European route E18* E18, a postcode district in the E postcode area...

 to continue 1 km through am open grassland in it natural meandering shape past some allotment-gardens
Allotment (gardening)
An allotment garden, often called simply an allotment, is a plot of land made available for individual, non-professional gardening. Such plots are formed by subdividing a piece of land into a few or up to several hundreds of land parcels that are assigned to individuals or families...

 near Tensta
Tensta
Tensta is a district in Spånga-Tensta borough, Stockholm, Sweden. There are about 6,000 apartments in Tensta and a population of 17,083 as of December 31, 2007....

 before reaching the ponds in the park of Hjulsta
Hjulsta
Hjulsta is a working-class suburb of Stockholm. It is considered being part of Tensta, but with its own subway station which was opened in 1975 and is the end station of the blue line....

. The stream is guided under the central commercial district of Spånga through a tunnel 1.4 km long, opening out near Bromsten
Bromsten
Bromsten is an upper middle-class district of northwestern Stockholm and belongs to the Spånga-Tensta borough. The ruins of an ancient hill fort located in the area are believed to be the source of the district's name.- External links :* - homepage...

 industrial area, and receiving stormwater from surrounding areas. It then flows past the residential neighbourhood Bällsta before reaching two ponds in a park and receiving water from a second ditch (Nälsta dike) bringing water from residential areas at Nälsta, Flysta
Flysta
Flysta is a part of the congregation Spånga in the western-most parts of Stockholm municipality. It is a part of the Spånga-Tensta borough. Despite its location in a predominantly residential suburban area, this community has much of what smaller villages used to have, e.g. a bakery, grocery shops,...

, and Solhem. It then flows through the harness racing
Harness racing
Harness racing is a form of horse racing in which the horses race at a specific gait . They usually pull a two-wheeled cart called a sulky, although racing under saddle is also conducted in Europe.-Breeds:...

 track Solvalla
Solvalla
Solvalla is a horse racing track located in Bromma, Stockholm, Sweden. It was opened in 1927 and is the biggest harness racing venue in the Nordic countries. The last Sunday in May, Solvalla annually hosts Elitloppet, one of trotting's most prestigious international events.-Elitloppet:*...

 where the water is used for fountains during races. Downstream Solvalla, it becomes broad with a slow flow occasionally becoming stagnant. Bällstaån finally receives water from Rissne
Rissne
Rissne is an area in Sundbyberg Municipality in Stockholm urban area, Sweden.Rissne has a metro station, inaugurated on August 19, 1985, and is home to several businesses.-References:...

, Duvbo
Duvbo
Duvbo is a residential area in Sundbyberg in suburban Stockholm, Sweden.The Duvbo metro station is located in central Sundbyberg, just outside Duvbo and is part of the Stockholm Metro. It was inaugurated on August 19, 1985....

, and Sundbyberg before emptying into Bällstaviken under the bridge Löfströmsbron.

Environmental influence

As most of the inflow comes from settled grounds, including industrial areas and streets, the stream contains high levels of nutrients, metals and bacteria, with sediments contaminated with oil. The river receives 1400 kg/year of phosphorus
Phosphorus
Phosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks...

 and 16000 kg/year of nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...

. Increased levels of pollutants and bacteria downstream Spånga is believed to stem from stormwater pipes but no source have been identified. Increased levels of metals, particularly copper, has been reported, and minor oil discharges are rather common with negative impact on local bird life.

Flora and fauna

No inventory of aquatic plant
Aquatic plant
Aquatic plants are plants that have adapted to living in aquatic environments. They are also referred to as hydrophytes or aquatic macrophytes. These plants require special adaptations for living submerged in water, or at the water's surface. Aquatic plants can only grow in water or in soil that is...

s has been made, but Greater Dodder has been documented around the Lunda Industrial Area. No rare species of bottom fauna were found during an inventory in 1999, the stream being quantitatively dominated by a few species. Noteworthy is the gastropoda Valvata piscinalis
Valvatidae
Valvatidae, the valve snails, is a taxonomic family of very small freshwater snails with an operculum, aquatic gastropod mollusks.- Taxonomy :...

 found near the residential area Bällsta. The stream is, nonetheless, important for various birds, including Black-headed Gull
Black-headed Gull
The Black-headed Gull is a small gull which breeds in much of Europe and Asia, and also in coastal eastern Canada. Most of the population is migratory, wintering further south, but some birds in the milder westernmost areas of Europe are resident...

, Common Gull
Common Gull
The Common Gull or Mew Gull Larus canus is a medium-sized gull which breeds in northern Asia, northern Europe and northwestern North America. It migrates further south in winter...

, Lesser Black-backed Gull
Lesser Black-backed Gull
The Lesser Black-backed Gull is a large gull that breeds on the Atlantic coasts of Europe. It is migratory, wintering from the British Isles south to West Africa...

, Herring Gull, and Slavonian Grebe
Slavonian Grebe
The Horned Grebe or Slavonian Grebe, Podiceps auritus, is a member of the grebe family of water birds. The Slavonian Grebe is an excellent swimmer and diver, and pursues its fish prey underwater...

 reported at Hjulsta Water Park. As stretches of the watercourse remains ice-free during winters, it attracts duck
Duck
Duck is the common name for a large number of species in the Anatidae family of birds, which also includes swans and geese. The ducks are divided among several subfamilies in the Anatidae family; they do not represent a monophyletic group but a form taxon, since swans and geese are not considered...

s and Common Teal
Common Teal
The Eurasian Teal or Common Teal is a common and widespread duck which breeds in temperate Eurasia and migrates south in winter. The Eurasian Teal is often called simply the Teal due to being the only one of these small dabbling ducks in much of its range...

has been seen spending winters here.

External links

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