River Flooding and Management
How do systems ideas help us to understand physical processes that operate in a river
basin?

The study of water systems in the atmosphere and river basins.
The units and links in the hydrological cycle.

The hydrological cycle.
The storm hydrograph and how it responds to changes.

The river basin as a local system.
The river basin as a system of inputs, flows, stores and outputs.
(b) How does river flooding illustrate the interaction between natural processes and human
activity?

The different causes of river flooding.
Physical causes of river flooding.
The activities of people that can cause river flooding.

The effects of river flooding

Some strategies for flood management are more sustainable than others
Key Terms Definitions
Key Term
Evaporation
Condensation
Infiltration
Percolation
Throughflow
Groundwater flow
Surface Runoff
Groundwater store
Interception
Transpiration
Saturated
Permeable
Impermeable
Precipitation
Definition
Soil
Rock
Key Term
Drainage Basin
Definition
Watershed
Confluence
Tributary
Source
Mouth
What would happen if….
1. There was a lot of intense rainfall in the basin?
2. There was only a little rainfall in the basin?
3. The whole area had been deforested?
4. The basin was contained a lot of impermeable surfaces?
Describe the route water may take when falling in a drainage
basin, using inputs, stores and processes.
(5 marks)
Peer Assessment
Circle all the connectives – CATTs
Highlight in one colour inputs
Highlight in another colour processes
Highlight in another colour the stores
Highlight in another colour the outputs
A rivers response to a rainfall event
Hydrographs
Match the terms
Key Term
Discharge
Definition
When the discharge in the
river begins to increase.
Peak Rainfall
The time between Peak
Rainfall and Peak Discharge
Peak Discharge
When Discharge in the river
begins to fall again
Rising Limb
The amount of water
passing a given point at a
given time
Falling Limb
The highest
rainfall
Lag Time
The point at which water is
at its highest
amount
of
Flash response – water gets to
the river quickly
Lag response – water gets to the
river quickly
Flooding
How might the following factors lead to flooding?
Physical Factors
Intense Rainfall
Thin Soil
Impermeable
Geology
Steep Valleys
Confluence of a
river
Human factors
Deforestation
Urban areas
Climate change
How does the factor lead to flooding?
Managing Flood Risk in the UK
Carlisle Case Study, Cumbria
The Carlisle Floods of January 2005
Carlisle is situated on the flood plain of the River Eden with three rivers meeting in the city. The catchment
covers approximately 2400km2 and is home to approximately 244,000 people. The catchment is mainly
rural, with only 1% classified as urban: the main urban areas are Carlisle, Penrith and Appleby.
Carlisle has a history of flooding with flood events recorded as far back as the 1700s. In recent years there
have been significant floods in 1963, 1968, 1979, 1980, 1984, and recently in 2005.
Across the catchment, the January 2005 flooding affected 2,700 homes. In Carlisle three people died, 1,844
properties were flooded and there was significant disruption to residents, businesses and visitors. The cost of
the flooding was estimated at over £400 million. The flooding followed prolonged heavy rain, and was
caused by a combination of floodwater from the Rivers Eden, Pettereril and Caldew and localised flooding
from sewers and road drainage.
As a result of this flooding, the Environment Agency has prepared a flood management plan.
The catchment of the River Eden is in Cumbria, rising in the hills of the Lake District. It reaches the sea at
the Solway Firth. The catchment is made up of the Rivers Eden, Eamont, Irthing, Petteril and the Caldew, as
well as smaller rivers and streams draining into the Eden estuary.
<img
src="/image/page/GA_FloodingCarlisleDrainageBasin.jpg" alt="Drainage basin of the River Eden" />
The catchment has a history of flooding with Carlisle, Penrith and Appleby at greatest risk. The flood risks
to people and property within the Eden catchment are from:




Limited capacity at the Thacka beck culvert, which causes flood risk to Penrith
The River Eden, which affects several urban areas including Carlisle, Kirkby Stephen, Appleby and Lower
Crosby
The Rivers Caldew and Petteril, which affect Carlisle
Flooding from the River Eamont at Eamont Bridge
Topography
The upper parts of the catchment are dominated by the mountains of Skiddaw and the surrounding fells. The
rocks here are hard and volcanic, soils are thin and the gradients of many tributaries are steep, so these
watercourses have a rapid run-off response to flooding. In the lower reaches rivers flow through wide,
shallow valleys.
The Eden channel itself has a steep gradient upstream of Kirkby Stephen. The head of the catchment is
around 690m, falling rapidly to 160m at Kirkby Stephen. Below Kirkby Stephen, the Eden's glaciated valley
opens out and the channel gradient reflects this change: the River Eden steadily loses height at around 1.8m
per km to Appleby at 123m some 21km downstream.
From Appleby, the Eden continues through the lowland valley to Carlisle, 9m, falling at a fairly constant
rate of 1.4m per km over its 80km journey from Appleby. The valley floor is over 2.5 km wide in many
places. This forms extensive areas of floodplain washlands which are an important feature of the catchment.
Hydrology
In the Eden catchment there is a significant contrast in mean annual rainfall between the upstream and
downstream ends of the catchment, related to the topography of the catchment.


In the upland tributaries upstream of Penrith in the Eamont catchment, average annual rainfall exceeds
2800mm on Helvellyn
Around Carlisle and on the coastal fringe, this is reduced to about 760mm
The average annual rainfall for England and Wales is 920mm
Describe the pattern of rainfall and discharge for the River Eden in January 2005
Read and Highlight the main causes of the flooding in Carlisle in the article
above
To what extent were Physical factors responsible for the Carlisle flooding?
What were the impacts of the flooding?
Annotate the photograph and the OS map to show the human features affected by the
flooding
Flood Management
Strategies
Soft Engineering
Monitoring of the river
level
Soft engineering
Land Use Zoning
Soft Engineering
Afforestation
How does it prevent
flooding?
Advantages
Disadvantages
Hard Engineering
Widening and Deepening
and Straightening the
River
Hard Engineering
Building a Dam upstream
Hard Engineering
Building Embankments
STAKEHOLDERS:
-
Home Owners
Local businesses
Local Council
National Government
Emergency Services
Insurance Companies
Flood Defence Engineers
Flood Management Researchers
Tax Payers
Car Owners
Environmentalist
Meteorologists
Local residents
Colour code the stakeholders who would be
for or against building flood management
strategies
Explain why different stakeholders have different views on how to manage river flooding?
____________________________________________
____________________________________________
_____________________________________________
____________________________________________
____________________________________________
_____________________________________________
The Decision: Flood Management Strategies for Carlisle
Option 1: Monitoring the river level and providing a warning system for local people
Option 2: Floodplain Zoning – the local authorities dividing up the floodplain into different land uses and
enforcing these by law
Option 3: Hard Engineering at a local level, straightening and enlarging the river channel and also building
flood defences such as levees
Option 4 : Hard Engineering at drainage basin level, building Dams and Reservoirs in the Upper course of
the river.
a) Chose one of the above options, and explain why you think it is the most sustainable,
b) Suggest possible disadvantages of your chosen option
c) Select one of your rejected options and state why this methos is not as sustainable as your option
d) Explain why one flood management method alone is unlikely to solve the issue of flooding in
Carlisle
____________________________________________
____________________________________________
_____________________________________________
_____________________________________________
_____________________________________________
_______________________________________________
_______________________________________________
_______________________________________________
_______________________________________________
_______________________________________________
_______________________________________________
_______________________________________________
_______________________________________________
_______________________________________________
_______________________________________________
_______________________________________________
_______________________________________________
_______________________________________________
_______________________________________________
_______________________________________________
_______________________________________________
_______________________________________________
_______________________________________________
_______________________________________________
_______________________________________________
_______________________________________________
_______________________________________________
_______________________________________________
_______________________________________________
_______________________________________________
_______________________________________________
___________________________________
DME - Geography
Level 1 (1-4 Marks)
Gives one or two reasons for choice.
Level 2 (5-8 Marks)
develops one reason for choice ( using
Level 3 (9-12 Marks)
developed explanation of choice
PEE)
explains one reason with detail
basic development of choice and
in grammar and spelling
Thorough development ( using PEE)
in reasons for choice and rejection
give reasons why the other choice was
explanation of why the chosen
explanation of why the chosen
rejected
option is more sustainable than
option is more sustainable than the
the other option
other option using S.E.E
explanation of why one method
Developed explanation of why one
alone will not solve the problem of
method alone will not solve the
flooding
problem of flooding
spelling grammar and punctuation
Good use of geographical
are accurate
terminology. Very accurate and
attempts to discuss sustainability
reasons for rejecting the other option
written work contains some mistakes
Level 4 (13-16 Marks)
mostly accurate spelling and grammar
precise written language, spelling
and grammar
Overall Mark:
:
What went well:
Even better if:
What they actually did in Carlisle on the River Eden