water course

 A stream of water; a river or brook.  Isa. xliv. 4.  [1913 Webster]

 A natural channel for water; also, a canal for the conveyance of water, especially in draining lands.  [1913 Webster]

 A running stream of water having a bed and banks; the easement one may have in the flowing of such a stream in its accustomed course. A water course may be sometimes dry.  Angell. Burrill.  [1913 Webster]