Transcript Lesson 1 The Drainage Basin Hydrological Cycle

An Introduction to
Hydrology
Lesson 1
The Drainage Basin
Hydrological Cycle
L.O. To understand the drainage
basin hydrological system
Can
youDrainage
write a dictionary
for these
words?
The
Basin definition
Hydrological
Cycle
Stemflow
Precipitation
Surface Storage
Percolation
Drainage
Basin
Precipitation
The fallout of water drops or frozen particles from the atmosphere
(McGraw-Hill Dictionary of Environmental Science, 2008)
Surface Storage
The part of precipitation retained at the ground surface
(McGraw-Hill Dictionary of Environmental Science, 2008)
Stemflow
‘The flow of water down the trunk or stem of a plant’
(wikipedia)
‘The process that directs precipitation down plant branches and stems’
(geography-dictionary.org)
Drainage Basin
‘The area of land drained by a
river and it’s tributaries’
(Barker, Redfern and Skinner, p.13, 2008)
A drainage basin may also be
called a ‘catchment’
Where’s the watershed??
The Hydrological
Cycle
The Drainage
Basin Hydrological
Cycle
There is a fixed amount of water circulating in our
atmosphere and on its surface. There are no exchanges
outside the earth and its atmosphere. It is therefore a
CLOSED SYSTEM, which means that there are no
INPUTS or OUTPUTS of water but only of energy.
Water is continuously cycled
between the oceans, the land, and
the atmosphere as the GLOBAL
HYDROLOGICAL CYCLE.
•Draw a copy of Fig 1.4
•Can you label any of the
arrows to show the
processes by which
water is moving?
The Drainage Basin Hydrological Cycle
The part of the hydrological cycle that occurs within a drainage basin.
The hydrological cycle is a closed system but the drainage basin is an open
system with inputs, and outputs as well as transfers and stores.
you construct
own drainageCycle
The Can
Drainage
Basinyour
Hydrological
basin hydrological cycle?
Use the cards to construct your own
version of the DBHC
Draw arrows between the cards to
show how they are linked
Throughflow
You must be able to justify why you put
each card in a particular place.
When you’re done colour code each
card to show if it’s an input, store,
transfer or output
End!
Copy and complete
the following Cycle
The Drainage
Basin Hydrological
paragraphs into your notes:
The drainage basin (or catchment) is the area of land drained by a
__________ and ___ ___________. An imaginary line called the
__________ separates one drainage basin from another. This follows a
ridge of highland; any rain falling on the other side of the ridge will flow
into another river in the adjacent drainage basin.
The drainage basin hydrological cycle is the part of the hydrological
cycle that occurs within a _______ _______. Unlike the hydrological
cycle it is a closed/open system. The DBHC is made up of ______ and
______, which can vary greatly over _______, ________ and ________.
What couldBasin
I be asked
in the exam?Cycle
The Drainage
Hydrological
Give a detailed definition of any of the key words in the DBHC
Fill in gaps on a diagram of the DBHC
Explain how human activities could modify the DBHC
Throughflow
Evaporation
Overland flow
Transpiration
Groundwater flow
Percolation
Vegetation Storage
Throughfall and
Stemflow
Surface Storage
The movement of water
over the surface of the
ground to rivers
Water drains down
through rocks towards the
water table
The water table is the upper level
of groundwater.
The part of precipitation
retained at the ground
surface
Water changes from a liquid
to a gas and is returned to
the atmosphere
Water moves horizontally
through the soil under
towards rivers.
Evaporation is facilitated by
energy from the sun
Normally happens when the soil
is completely saturated with
water.
Water flows through rocks
towards the river.
This is affected by rock type e.g. if
the rock is permeable or not.
Precipitation drips through
vegetation to the ground
Precipitation runs down the
stems of plants or trunks
of trees to the ground.
Water evaporates from
inside vegetation and is
returned to the
atmosphere.
Plants can control the rate of
transpiration by opening and
closing their stomata
Water is stored within
plants and trees.
Groundwater flow
(Base flow)
Channel Storage
Channel Flow
Groundwater Storage
Infiltration
Interception
Precipitation
River Runoff
Soil Water
Water and ice that fall
from clouds into the
drainage basin.
It can take many forms and vary
greatly over time and space
The total discharge of
water from the drainage
basin via its’ main river
Water is stored
in the soil
Water is stored in
permeable rocks below the
surface of the ground
The process by which
water enters the soil
The rate can be affected by
factors such as soil type, soil
saturation and duration of rainfall
Precipitation is trapped or
stored temporarily on
vegetation
Water flows through
rocks towards the river.
The rock type can affect
the rate of flow
Water is stored
in a river
It is the amount of
water stored in a river at
a particular instant.
Water flows in a river
This is the most efficient
means of removing water
from a drainage basin
Water flows through
rocks towards the river.
The rock type can affect
the rate of flow
Water is stored
in a river
It is the amount of
water stored in a river at
a particular instant.
Water flows in a river
This is the most efficient
means of removing water
from a drainage basin
Water is stored in
permeable rocks below the
surface of the ground
The process by which
water enters the soil
The rate can be affected by
factors such as soil type, soil
saturation and duration of rainfall
Precipitation is trapped or
stored temporarily on
vegetation
Water and ice that fall
from clouds into the
drainage basin.
It can take many forms and vary
greatly over time and space
The total discharge of
water from the drainage
basin via its’ main river
Water is stored
in the soil
Learning Outcomes
All will be able to describe the main features of the
DBHC and define most of the key processes.
Most will be able to draw a sketch of the cycle,
define all the key processes within in and explain
how they are interlinked.
Some will be able to explain the spatial and
temporal variations that exist and explain how
human activities can affect specific processes
within the cycle.