Magelungsdiket () is one of three inflows of Lake Magelungen in southern Stockholm, Sweden. It empties into the lake from north together with Kräppladiket while DjupÃÂ¥n reaches the southern end of the lake.
Magelungsdiket had a drainage area of 17 km<sup>2</sup> stretching north to Mälarhöjden until the south-western suburbs of Stockholm were built in the early 1950s and water was guided to Lake Mälaren through stormwater pipes. Today only 1,5 km<sup>2</sup> remains of the drainage area and most of the contributions comes from one-family houses in eastern RÃÂ¥gsved and green areas around Magelungen. Water flow is slow, often stagnant, and the ditch is surrounded by dense vegetation. It opened out in a wetland drained in 1994 in order to create canals and minor islands attracting birds. Very high levels of metals have been reported from a street inlet near the outlet. Together with Kräpplingadiket, it is estimated to contribute some 100 kg/year of phosphorus. The ditch is one of a few locales for Grass Snake in Stockholm.