Water Flow and
Level
A basin's flow
regime is driven by the local climate. The behaviour of
the water, once on the ground, and its ability to form channels is
controlled by the underlying geology and landcover, and more
recently landuse. The main factors that influence flow regime are
the amount of infiltration to groundwater and evapotranspiration,
which in essence determine the amount of runoff and surface water
Surface Water Flow
Within a basin's flow regime, there are four
flow stages that have significance to the form of the channel
and valley as well as the ecology of the system.
Water Levels and Flows
The four flow stages are:
- valley or floodplain flows,
- riparian flows,
- bankfull or channel defining flow,
- and baseflow.
Valley/Floodplain flows are high magnitude flooding events that
have a frequency varying from 25 to 100 years.
Riparian flow refers to high flows that access parts of the active
floodplain on a fairly regular basis (for example seasonally,
every spring and/or fall).
Bankfull or channel defining flow is the maximum flow within a
channel before spilling onto its floodplain.
Baseflow has the lowest discharge
on an annual basis and usually occurs during the summer
months.
