thalweg(line that connects the lowest points in a valley or river channel) noun [UK: θˈalweɡ] [US: θˈælweɡ]The continuous flow of water forms thalwegs in the lower parts of the valleys. = El continuo fluir del agua forma vaguadas en las partes más bajas de los valles.
trough [troughs](a linear atmospheric depression associated with a weather front) noun [UK: trɒf] [US: ˈtrɒf]