Rectangular draina
Rectangular drainage system
Rectangular drainage develops on rocks that are of approximately uniform resistance to erosion, but which have two directions of jointingat approximately right angles. The joints are usually less resistant to erosion than the bulk rock so erosion tends to preferentially open the joints and streams eventually develop along the joints. The result is a stream system in which streams consist mainly of straight line segments with right angle bends, and tributaries join larger streams at right angles.