The Gammelbacka stream, also called Storängsbäcken, flows from the forests of Kuninkaanportti and Ernestas through Eestinmäki and Karjalaiskylä fields through the built-up urban area and park area of Gammelbacka to the issue of river Porvoonjoki. The length of the stream is about seven kilometers. Salmo trutta have been restocked in Gammelbacka stream in the urban area and park area. This part of the stream was restored in 2014.
Storängsbäcken has its own Drainage corporate body. Drainage corporate bodies are organizations that consist of those land owners that gets benefit or profit of the drainage. Drainage corporate bodies have been established in Finland since 1883 for maintaining the ditches. Storängsbäckens Drainage corporate body was established in 1932. First drainage plans have been made in 1916.
The most of drainage corporate bodies are not active and maintenance of the ditches has been delayed. Many cases drainage corporate body has not been active in 50 years. Farmers are trying to excavate small shots of the ditch in their own lands with locally-based contractors and the results are largely qualitatively weak.
The drainage main channel of Storängsbäcken is a typical case, not renovated during decades. The problems consist of small difference of field surfaces and channel water level. By drainage planning norms this difference should be at least 80 cm. This problem was caused by erosion which resulted silt and mud accumulation to the channel and also depression of the soil. Humidity and floods have during the years compressed and weakened soil structure and farming capacity, and also increased depression.