Geomorphology
Geomorphology is the study of landforms, their
processes, form and sediments at the surface of
the Earth (and sometimes on other planets).
• Study includes looking at landscapes to work out
how the earth surface processes, such as air,
water and ice, can mould the landscape
• Landforms are produced by erosion or
deposition, as rock and sediment is worn away by
these earth-surface processes and transported
and deposited to different localities.
• The different climatic environments produce
different suites of landforms.
• The landforms of deserts, such as sand dunes and
ergs, are a world apart from the glacial and
periglacial features found in polar and sub-polar
regions.
• Geomorphologists map the distribution of these
landforms so as to understand better their
occurrence
, Geomorphology
• Earth-surface processes are forming landforms today, changing the
landscape, albeit often very slowly.
• Most geomorphic processes operate at a slow rate, but sometimes
large event, such as a landslide or flood, occurs causing rapid chang
to the environment, and sometimes threatening humans.
• So geological hazards, such as volcanic eruptions, earthquakes,
tsunamis and landslides, fall within the interests of geomorphologi
• Advancements in remote sensing from satellites and GIS mapping h
benefited geomorphologists greatly over the past few decades,
allowing them to understand global distributions
, Drainage systems in SA
• Drainage system
• Refer to river systems
• A number of small streams and rivers join to form a river system
• A river is a body of water flowing downslope in a defined channel from a
source to a mouth
• Drainage basin and catchment area
• The area drained by a river system or stream network is called the drainag
basin
• The catchment area is the drainage area that supplies water to a river
• This water comes from the rainwater that flows down the slope of the hig
ground, as well as from the underground water that seeps into the river
• The are of land forming the catchment area of a river is not always the sam
size as the drainage basin as it is determined by the origin of underground
water
, Drainage systems in SA
• What happens to the precipitation that falls in a drainage basin?
• A drainage basin is an open system of inputs, stores, flows and outputs
• The drainage basin collects precipitation, allows water to infiltrate or seep
underground to become groundwater, and store water in lakes, in wetland
and underground
• Rainwater that does not infiltrate underground flows over the surface as
surface runoff
• This runoff flows into streams that join the main river that flows our of the
basin – eventually this water flows into the ocean when the river reaches
level
• Precipitation that does not infiltrate underground or flow over the surface
may evaporate, be intercepted by vegetation or be transported as water
vapour