Question

factor that affect the drainage pattern of area?

Answer 1

topography, soil type,bedrokck,climate and vegetation
cover.

Answer 2

3 Factors that influence the development of drainage pattern are:
Slope of the land. The direction of the river Flow is generally guided by the direction of the slope since the flow of the water is controlled by gravitational force. There are rivers whose flow is exclusively determined by the direction of the slope. Difference in rock resistance or hardness. As the river erode its channel, the nature of the bedrock becomes significance in determining how deep the river channel will become. If the river encounter a very resistant rock outcrop in its path, it may have to change its direction to circumvent it despite the nature of the slope. 
The rock structure along the river's profile. At certain stages in the course of the river , The arrangement of rock layers may influence the direction that river takes. The river may change its direction due to the direction of the strike of an exposed rock layer despite the general direction of the flow.