The lake empties to the west through Gömmarbäcken ("Gömmaren Rill") and to the east through Fullerstaån ("Fullersta Stream"), which is further downstream guided in culverts under the commercial centre of Huddinge (Huddinge Centrum) before flowing south-east to empty into Lake Trehörningen. Motorboats are not allowed on the lake. Its clear water makes it popular for various open-air activities such as angling and bathing in summer, and skating in winters as it is one of the first lakes in Huddinge to freeze. Bathing from cliffs surrounding the lake is popular, but a sand beach is also available. A local fishing society (Långsjön-Gömmarens Fiskevårdsförening) manages lake conservation and supplies the general public with fishing permits.[3]
History
Notwithstanding the lake's name, documented from the 18th century and most likely hinting at the hidden away location, settlements have been present near the lake since the Stone Age.[4] The property of Vårby Gård, a nearby homestead, used to reach the lake in the 18th century, but the central building burnt down in 1975 and none of its gardens, brewing, bakery, smithy, or poultry houses are left.[5]
Catchment area
The lake is located in a forest forming part of the Gömmaren Nature Reserve created in 1995 and as such is considered as important for recreation and nature conservation, a popular destination both for lovers of open-air life and for schools.[3]
Environmental influence
The water of the lake is very clear and virtually colourless, which reflects the nutrient-poor flat rockpine forest of the surrounding area. Settlements south of the lake provide most of the nutrient contribution to the lake and about 80 per cent of the phosphorus input. A hydrogeological examination in 1985 showed the surrounding soil is poorly fit to take up increased levels of waste water. Acidification has been neutralized by liming which has produced excellent pH-levels.[3]