682067
Description
Mind Map by Andrew_Ellinas, updated more than 1 year ago
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Created by Andrew_Ellinas
over 10 years ago
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Rivers, Floods and Management:
Drainage Basin Hydrological Cycle
- What is a Drainage Basin?
- A drainage basin is the area of
land that is drained by a river and
its tributaries.
- The drainage basin acts largely as a
'closed' system, because it has a very
definitive outer edge or boundary
called the watershed.
- Key Words
- Precipitation: The type, total
amount and intensity are key
factors in determining the nature of
water movement.
- Evapotranspiration: When water loss from the
ground surface to the atmosphere (evaporation),
combines with water loss from plants
(transpiration) to form the main output from the
system.
- Interception: Vegetation, especially trees, intercepts
some precipitation on its way to the ground. Water is
then lost back into the atmosphere by
evapotranspiration. intercepting plants also use the
water for growth.
- Depression Storage: When water is
stored temporarily on the ground
surface in the form of puddles
- Soil Moisture: If soils is saturated, precipitation will
flow as overland flow. Clay soils are wet and boggy
(leading to overland flow). Sandy soils are much
drier so have the opposite effect.
- Baseflow, or Groundwater Flow:
This is a very slow transfer of
water through rocks.
- River Channel: This is the river
itself. Also forms the 'exit' for
water transferred through the
drainage basin
- Percolation: This is the deeper transfer
of water into permeable rocks - those
with joints (pervious), or those that are
porous.
- Throughflow: Downhill transfer of
water of water through the soil
layer to the river.
- Infiltration: Water moving
from the ground surface into
the soil.
- Overland Flow: Rapid
form of water transfer
over the surface of the
ground.
- Precipitation: The type, total
amount and intensity are key
factors in determining the nature of
water movement.
- A drainage basin is the area of
land that is drained by a river and
its tributaries.
- The Water Balance
- In order to get a better understanding
of water resources in a drainage
basin, we use an equation called the
water balance.
- P = O + E +/- S
- P = Precipitation
- O = Total runoff (streamflow)
- E = Evapotranspiration
- S = Storage (in soil or rock)
- P = Precipitation
- An important aspect of the
equation is the amount of
runoff - expressed as a
percentage of precipitation.
It is a measure of the
proportion of total
precipitation that makes its
way into streams and rivers
- In order to get a better understanding
of water resources in a drainage
basin, we use an equation called the
water balance.
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