 It has a relatively small catchment area; other streams flow parallel to it on either side.The Winster is about 20 km or 12 miles long, and rises about 2 km south of Bowness-on-Windermere, between the hamlets of Winster and Storrs (the latter is on Windermere) and follows a southerly course, flowing past the settlements of Ludderburn, Hartbarrow and Bowland Bridge, before it is joined by Arndale Beck at Bridge House.From there, the river continues through a valley between Whitbarrow and Cartmel Fell, flowing through Helton Tarn.