1 The drainage basin hydrological system is a
summary of a single river basins characteristics:
INPUTS- Precipitation, solar energy for
evaporation. OUTPUTS- Evaporation, run-off.
2 WHAT IS A SYSTEM?
2.1 A system is an orderly process which remains constant and includes:
stores, flows and processes.Systems can be categorized as either open,
closed or isolated. E.G. Hydrological system is closed, while the drainage
basin system is open.
2.2.1 VERTICAL FLOWS - Natural flows due to gravity. It is only when impeded (stopped),
that horizontal flow will take place.
2.3 SPEED OF FLOWS
2.3.1 INFILTRATION CAPACITY RATE- max. rate which water passes through soil (mm/hr).
PERCOLATION- water movement slows as it reaches more compact underlying rock/soil
2.4 HORiZONTAL FLOWS
2.4.1 SURFACE RUN-OFF/OVERLAND FLOW: fastest flow.
THROUGH-FLOW- lateral movement of water through upper soil layers.
GROUNDWATER FLOW/BASE FLOW- slow lateral movement of water
from underlying bedrock/ soil layers beneath the water table.
2.5.1 FIELD CAPACITY- The level to which soil moisture stores can fill up before it is drained, due to gravity
(how much water the soil can hold before saturation.