18.6 kilometres ( 11.6 mi ) northwesterly forming a large northeasterly curve .
18.6 kilometres ( 11.6 mi ) northwesterly winding to the confluence of the Pierrefonds River ( coming from the northeast ) ;
18.6 kilometres ( 11.6 mi ) northwesterly forming a large northeasterly curve and winding to the confluence of the Pierrefonds River ( coming from the northeast ) ;