Global hydrologic system

Hydrological cycle is a system which comprise of components like precipitation, infiltration, runoff and evaporation. A hydrological system can be defined as a structure in space, bounded by a defined boundary that accepts rain water and or other inputs, operates on them internally, and produces them as outputs. The global hydrological system consists of three parts. They are atmospheric water system, surface water system and sub-surface water system. Precipitation, interception, transpiration and evaporation take place in atmospheric water system. Overland flow, surface run-off, sub-surface outflow, groundwater outflow and runoff to the streams and the oceans Take place in the surface water system.  Infiltration, groundwater recharge, sub-surface flow and groundwater flow take place in sub-surface water system.