Bolska

thumb|The average monthly discharge of the Bolska at Dolenja Vas, Prebold|Dolenja Vas (1971–2000) The Bolska is a river in Slovenia that flows for 32 km before joining the Savinja as its largest and longest right tributary. Its watershed covers 190.3 square kilometres of transitional territory in central Slovenia, stretching from the Sava Hills to the Menina and Dobrovlje karst plateaus and extending to the southwestern edge of the Celje Basin. The river rises northwest of Trojane at an elevation of about 815 metres and descends to its confluence with the Savinja near Prebold at 264 metres. The Bolska and its numerous torrential tributaries are characterised by a pluvial regime with seasonal flooding, making the watershed particularly prone to catastrophic flood events, as demonstrated by the devastating storm of June 1994.

==Geography== The Bolska is the largest and longest right tributary of the Savinja River in Slovenia's Savinja Valley. Its watershed covers of transitional territory in central Slovenia. The river rises northwest of Trojane at an elevation of approximately between Reznarca Hill () and Javorje Hill (), and flows into the Savinja River near Prebold at . The total length of the Bolska is between and , with an average gradient of 13.8 to 17.2‰.