Lilla sjö (Hästveda socken, Skåne)

Lilla Sjö is a lake in the municipality of Hässleholm in Skåne and is part of the main catchment area of the Helge River.

However, due to the lack of a functional wastewater treatment plant, non-existent filtration from peat mining at Åbuamossen, and phosphorus and nitrogen leaks from households and agriculture, it became difficult for the lake to survive on its own.

Restoration began in the early 1990s by regulating the water level, cutting reeds, and moving the outlet of the nearby sewage treatment plant to a wetland south of the lake.

[2] The first step in the restoration of Lilla sjö was an extensive water and sewage treatment of Kvarnabäcken, the lake's main tributary.

The combined effect of these measures was a significant reduction in phosphorus and nitrogen levels in the northern part of the lake, leading to a decrease in algal bloom.

[2] The relief of Kvarnabäcken and the relocation of the sewage treatment plant's discharge point greatly improved the situation in the northern part of the lake by the late 1990s.

The Lilla å, which drains the catchment area, has a tributary order of 3, indicating that the water flows through a total of 3 watercourses before reaching the sea after traveling 70 kilometers.