# Laduviken
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> Source: https://en.wikipedia.org/wiki/Laduviken
> Source revision: 1275063190
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{{Short description|Lake in Stockholm, Sweden}}
{{Infobox body of water
| name = Laduviken
| image = Laduviken 070610 E.JPG
| caption =
| image_bathymetry =
| caption_bathymetry =
| alt = View of Laduviken
| location = [Royal National City Park](/source/Royal_National_City_Park), [Norra Djurgården](/source/Norra_Djurg%C3%A5rden)
| coords = {{coord|59|21|38.37|N|18|4|35.9|E|region:SE_type:waterbody_scale:30000|display=inline,title}}
| type =
| pushpin_map = Sweden Stockholm
| pushpin_map_alt = Location of Laduviken
| inflow = Local [stormwater](/source/stormwater)
| outflow = [Husarviken](/source/Husarviken), [Lilla Värtan](/source/Lilla_V%C3%A4rtan)
| catchment = {{convert|110|ha|abbr=on}}
| basin_countries = Sweden
| length =
| width =
| area = {{convert|5.3|ha|abbr=on}}
| depth = {{convert|2.2|m|abbr=on}}
| max-depth = {{convert|3.2|m|abbr=on}}
| volume = {{convert|117,000|m3|acre.ft|abbr=on}}
| residence_time = 3 months
| shore =
| elevation = {{convert|0.5|m|abbr=on}}
| frozen =
| islands =
| cities = [Norra Djurgården](/source/Norra_Djurg%C3%A5rden)
| reference = [Vattenprogram, p 1.1]
}}
'''Laduviken''' ({{langx|sv|Barn Bay}}) is a [lake](/source/lake) in [Norra Djurgården](/source/Norra_Djurg%C3%A5rden), a semi-rural area in north-eastern [Stockholm](/source/Stockholm), [Sweden](/source/Sweden), forming part of the [Royal National City Park](/source/Royal_National_City_Park). It is one of six lakes in [Djurgården](/source/Djurg%C3%A5rden), the others being: [Lillsjön](/source/Lillsj%C3%B6n%2C_Djurg%C3%A5rden), [Uggleviken](/source/Uggleviken), [Isbladskärret](/source/Isbladsk%C3%A4rret), [Lappkärret](/source/Lappk%C3%A4rret), and [Spegeldammen](/source/Spegeldammen).
== Catchment area ==
thumb|left|Historical map showing the area in the 17th century.
Most of the catchment area is composed of open grassland with scattered oaks and other [hardwood](/source/hardwood). West of the lake, the buildings of the [Stockholm University](/source/Stockholm_University) take up some 20 per cent of the surface and a few roads, a traffic route, the suburban railway [Roslagsbanan](/source/Roslagsbanan), and the subterranean metro passes through the area. East of the lake are some minor one-family houses and commercial buildings. The terrain north of the lake is flat while the southern shore is steep and, as the area west of the lake is drained by a ditch dug through a filled-up wetland, most of the catchment area is located there and most of the inflow comes from an ooze and oil separator treating water from human-made structures. A tiny river guides the outflow east to the bay [Husarviken](/source/Husarviken) which is part of the strait [Lilla Värtan](/source/Lilla_V%C3%A4rtan). In the late 1970s, the lake was deepened by dredging to prevent it from becoming choked-up during the 21st century, and a system of canals was then created in the western end of the lake. As part of a national park, the lake is considered as of great recreational value.[Vattenprogram, p 1.3-1.4]
=== Environmental influence ===
Most of the [phosphorus](/source/phosphorus) reaching the lake are most likely derived from the university, while [nitrogen](/source/nitrogen) contribution is derived from surrounding landscape and equal shares of [copper](/source/copper) input stems from all surrounding areas and structures. Generally the lake is considered as in good health with low levels of most metals and [organic compound](/source/organic_compound)s, even though presence of [hydrogen sulphide](/source/hydrogen_sulphide) has been recorded relatively frequently, levels of copper in top sediments did increase during the 1990s, and analysis's of subsoil water in 1997 showed signs of environmental contamination.[Vattenprogram, p 1.4-1.7]
The sparse fauna before the dredging of the lake, after 1995 evolved into a pretty considerable variety of species typical for shallow lakes rich in nutrients. Two species of freshwater snails, ''[Bithynia leachii](/source/Bithynia_leachii)'' and ''[Gyraulus crista](/source/Gyraulus_crista)'', were earlier considered as endangered. Noteworthy is also the population of several freshwater mussels, [duck mussel](/source/duck_mussel) and [swan mussel](/source/swan_mussel), and ''[Hippeutis complanatus](/source/Hippeutis_complanatus)'', the latter two declining. A species of [Oligochaeta](/source/Oligochaeta) new in Sweden has been reported in the lake just like did the rare [hairy dragonfly](/source/hairy_dragonfly). An inventory of dragonfly larvae in 2000 unveiled several other species (mostly [red-eyed damselfly](/source/red-eyed_damselfly) but also [common blue damselfly](/source/common_blue_damselfly), [azure damselfly](/source/azure_damselfly), [variable damselfly](/source/variable_damselfly), and [northern damselfly](/source/northern_damselfly) (''Coenagrion hastulatum''). Fish population reflects the shortage of oxygen with an absence of [carp bream](/source/carp_bream) and [silver bream](/source/Abramis) and an abundance of [perch](/source/perch), [roach](/source/Rutilus), and [crucian carp](/source/crucian_carp) dating back to before the dredging. The outlet forms a threshold for migrating species.[SNF]
== Visiting ==
The lake and the national city park are easily accessible by bus, metro, bicycle, or by foot. Nearest metro station is [Universitetet](/source/Universitetet_metro_station).