Drainage patterns are the patterns created by the river due to erosion over time. They reveal characteristics of the kind of rocks and geology of the area.$^{11}$
The drainage patterns of a given drainage basin is determined based on the topography of the land, whether or not the area is dominated by hard or soft rocks, and the gradient of the land.$^{11}$
This is by far the most common pattern. This is caused by the material under the river having no particular fabric or structure. It can be eroded in all directions equally easily.$^{11}$
This develops in areas of alternating weak and strong material. It will be easier for the river to erode in the parallel to the weak material.$^{11}$
In this pattern, the rivers originate from a single high point and radiate from it outwards. Volcanos generally have radial patterns.$^{11}$
This pattern develops in an area that has little to no topography. On top of that the area must have a system of bedding fractures or faults that form a rectangular network. These faults are where the rivers will easily erode.$^{11}$