▁economic ▁activity ▁in ▁the ▁sector ; ▁recre ational ▁activities , ▁second . ▁ ▁The ▁surface ▁of ▁the ▁Black ▁Be aver ▁River ▁( except ▁the ▁rap ids ▁areas ) ▁is ▁generally ▁fro zen ▁from ▁the ▁beginning ▁of ▁December ▁to ▁the ▁end ▁of ▁March , ▁but ▁safe ▁circul ation ▁on ▁the ▁ice ▁is ▁generally ▁made ▁from ▁the ▁end ▁of ▁December ▁to ▁the ▁beginning ▁of ▁March . ▁The ▁water ▁level ▁of ▁the ▁river ▁var ies ▁with ▁the ▁seasons ▁and ▁the ▁precip itation . ▁ ▁Geography ▁ ▁The ▁Black ▁Be aver ▁River ▁origin ates ▁from ▁" L ac ▁à ▁la ▁Po ê le " ▁( length : ▁; ▁alt itude : ▁) ▁in ▁the ▁un organ ized ▁territory ▁of ▁Lac - C ro che . ▁This ▁long ▁lake ▁is ▁mainly ▁fed ▁by ▁the ▁out let ▁of ▁Lac ▁de ▁la ▁Que ue , ▁the ▁out let ▁of ▁Lake ▁Cos , ▁the ▁out let ▁of ▁Lake ▁D ab in ▁and ▁the ▁out let ▁of ▁Lake ▁Tre tt é . ▁Its ▁out fall ▁is ▁located ▁at ▁the ▁bottom ▁of ▁a ▁bay ▁in ▁the ▁north western ▁part ▁of ▁the ▁lake . ▁ ▁The ▁course ▁of ▁the ▁river ▁str add les ▁the ▁boundary ▁of ▁the ▁administrative ▁regions ▁of ▁Capit ale - N ationale ▁and ▁Maur ic ie . ▁ ▁The ▁" riv ière ▁aux ▁Cast ors ▁No irs " ▁flows ▁to ▁the ▁bottom ▁of ▁a ▁bay ▁on ▁the ▁north ▁shore ▁of ▁a ▁lake ▁formed ▁by ▁the ▁w iden ing ▁of ▁the ▁Bat is can ▁River . ▁This ▁confl u ence ▁is ▁located