Located in the small park Lillsjöparken and surrounded by heavily trafficked artery roads on all sides, it is rich in nutrients with high levels of metals in the sediments.

Half of the catchment area is composed of forest and open terrain, part of series of parks constituting a local recreational resource.

While the inflow from the surrounding area contributed some 200,000 m³ annually, even small variations in water level in Lake Mälaren are of greater importance.

Three major artery roads and a ground-level metro track stretches through the area of which Bromma Airport forms a minor part.

Most of the nitrogen and more than half of the phosphorus stems from settlements in the area, while allotment gardens, generally lacking sewers, contribute nutrients.

No inventory of aquatic plants have been made since 1976, but the lake shares are dominated by reed with water lilies found in the southern part.