The Ter follows a course of 208 kilometres (129 mi) and drains an area of approximately 3,010 square kilometres (1,160 sq mi); its basin is described by a dendritic (branching, tree-like) and exorheic drainage pattern. Annually, an average of 840 cubic hectometres (680,000 acre⋅ft) of water is moved by the river, with an average flow rate of 25 cubic metres per second (880 cu ft/s) at its mouth. Although its headwaters are in the Pyrenees, the Ter receives significant inflow from rivers in the middle and lower plains. Thus it is susceptible to flooding in both the spring and the autumn.[1]