 The river's source is at Washburn Head, just south of Stump Cross Caverns and from there flows southwards via Thruscross Reservoir, Blubberhouses, Fewston Reservoir, Swinsty Reservoir and Lindley Wood Reservoir before joining the River Wharfe just north-west of Pool-in-Wharfedale.The Washburn has been dammed to a series of four reservoirs, all built to supply water to the city of Leeds.The lower three (Lindley Wood, Swinsty and Fewston) were built at the end of the 19th century, while the fourth, Thruscross, was delayed until the 1960s.