A drainage basin, also called a catchment area, is a region from which all precipitation, such as rain and melted snow, flows to a single stream or system of streams. By identifying such a basin, scientists can calculate denudation rates and moisture balances from from various hydrological measurements such as evaporation rates. The boundary of a drainage basin is called a watershed.
A drainage network is the relationship between the sizes, frequencies, lengths, and patterns of streams within a drainage basin. The drainage network can be analyzed in any combination of these variables to help describe the characteristics of a drainage basin.
A drainage system is the system by which surface water is collected and removed by streams, rives, and lakes. The pattern of drainage is determined by the type of rock and the slope of the land over which the water flows.