# Flaten
> Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Flaten
> Markdown URL: https://mediated.wiki/source/Flaten.md
> Source: https://en.wikipedia.org/wiki/Flaten
> Source revision: 1275063533
> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)
{{Short description|Lake in Stockholm, Sweden}}
{{other uses}}
{{Infobox lake
| name = Flaten
| image = Flaten, 2008-03-04.jpg
| image_size = 250
| alt = View of lake
| caption =
| image_bathymetry =
| caption_bathymetry =
| location = southern [Stockholm](/source/Stockholm)
| coords = {{coord|59|14|59|N|18|9|13|E|region:SE_type:waterbody_scale:100000|display=inline,title}}
| type =
| pushpin_map = Sweden Stockholm
| pushpin_map_alt = Location of lake
| inflow = Flatenån
| outflow = [Drevviken](/source/Drevviken)
| catchment = {{convert|403|ha|abbr=on}}
| basin_countries = Sweden
| length =
| width =
| area = {{convert|63|ha|abbr=on}}
| depth = {{convert|7.4|m|abbr=on}}
| max-depth = {{convert|13.6|m|abbr=on}}
| volume = {{convert|4.56|e6m3|acre.ft|abbr=on}}
| residence_time = 4 years
| shore = {{convert|5,460|m|abbr=on}} (including island)
| elevation = {{convert|21.9|m|abbr=on}}
| islands = 1 ({{convert|0.04|ha|sqft|abbr=on|disp=or}})
| cities = [Stockholm](/source/Stockholm)
| reference =[Vattenprogram, p 11.1][Vattenprogram, p 11.11]
}}
'''Flaten''' is a [lake](/source/lake) in southern [Stockholm](/source/Stockholm), [Sweden](/source/Sweden), located just north of Lake [Drevviken](/source/Drevviken). The name is also used for the surrounding area and the [nature reserve](/source/nature_reserve) created there in 2007.[Flaten blir naturreservat]
Flaten has the best water quality of all lakes around the Swedish capital and is highly popular for bathing and angling. The surrounding area is dominated by forests, with [allotment-gardens](/source/allotment_(gardening)) and some industrial activities located north of the lake. [Algal bloom](/source/Algal_bloom) occasionally occurs in spring.[Flaten]
== Catchment area ==
The undulating wooded grounds of the catchment area are considered as of significant natural value and, through the location within a nature reserve and proximity to Stockholm, also of significant recreational value. A scenic ravine is found by the southern end of the lake while most nearby settlements are located north of it. The area is used for various open-air activities including walking, bathing, camping, canoeing, and fishing.[Vattenprogram, p 11.3-11.4] The catchment area for [groundwater](/source/groundwater) is much larger than that for stormwater.[Vattenprogram, p 11.6]
=== Environmental influence ===
In summer, when the lake is stratified, bottom layers suffer of oxygen depletion causing release of [phosphorus](/source/phosphorus). Treatment with [aluminium chloride](/source/aluminium_chloride) in 2000, however, greatly reduced the amount of leaking phosphorus. Most of the [surface runoff](/source/surface_runoff) reaching Flaten comes from a ditch (''Flatendiket'') stretching a kilometre to empty in the northern end of the lake where two [sedimentation](/source/sedimentation) basins reduces the amount of pollutants reaching the lake. The ditch also receives [stormwater](/source/stormwater) from local settlements rich in nutrients and from the only road in the catchment area which contains metals and [PAH](/source/Polycyclic_aromatic_hydrocarbon)s. Occasionally, the ditch therefore transports waste water to the lake which the available [caisson](/source/Caisson_(engineering))s mostly fails to treat properly. However, pipes from the bathe lead to a local sewage disposal plant, and, additionally, the catchment area was reduced by some 20 per cent in 1978 when stormwater from the graveyard [Skogskyrkogården](/source/Skogskyrkog%C3%A5rden) was guided past the lake, which decreased pollution but also increased [lake retention time](/source/lake_retention_time).