Bolina

The Bolina is a stream located in southern Poland, within the Silesian Voivodeship, flowing through the cities of Katowice and Mysłowice. It stretches for 10.2 km and has a catchment area of 28.5 km². The main source of the Bolina is the Western Bolina (Bolina Zachodnia), which originates in the forests of Katowice. The stream flows through diverse landscapes and is fed by two main tributaries: the Southern Bolina I and II (Bolina Południowa I and II). Along its course, it supplies several ponds and eventually empties into the Czarna Przemsza River. The Bolina is highly anthropogenically altered, with a regulated channel along most of its length, which has significantly impacted its biodiversity. The highest ecological diversity is observed in the source section and around the ponds. The Bolina Valley and its ponds contain valuable natural areas that are home to rare species of plants and animals, including amphibians. However, the water quality of the Bolina is severely polluted, reaching the worst class (Class V) at its confluence with the Czarna Przemsza. The pollution primarily stems from industrial and mining activities. Within Katowice, the Bolina Valley once served as a natural ecological corridor, connecting forested areas with other rivers, but its ecological significance has been diminished by human-induced changes. Despite its water quality issues, the stream remains an important site for local recreational activities, including fishing, supported by fish farming in the ponds that feed into the Bolina.