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1. Explaining Floods with River Hydrographs

2. The Drainage Basin System
Q1. Make your own version of this diagram in your notebook under the
title ‘The Drainage Basin System’. Make sure to leave lots of space
for annotations around the sides of the diagram

3. Q2. In your notes copy the table below and then place each of the listed
terms/phrases into the appropriate part of the table:
Inputs Stores Transfers Outputs Factors influencing
movement of water
through the system
Infiltration, percolation, water table/ground water, interception,
evapotranspiration, gradient, rock permeability, vegetation, channel
flow, ground water flow, surface storage e.g. lakes, precipitation,
intensity of precipitation, duration of precipitation
Q3. Annotate your diagram (from activity 1) with the terms in the table
above to demonstrate how water moves through the system:

4. Physical factors influencing river discharge and flooding
Q4.
Two people in your group are going to create a list of physical
characteristics of drainage basins that will lead to maximum flooding
potential
Two people in your group are going to create a list of physical
characteristics of drainage basins that will lead to minimum flooding
potential
Drainage Basin Very Likely to Flood Drainage Basin very Unlikely to Flood

5. Human factors affecting river discharge and Q5. In your groups,
flooding use this sketch and
your own drainage
basin diagrams as a
stimulus to create a
list of as many
reasons why Metro
Manila experiences
worse floods in
2012 than Manila
did in 1912 as
possible. Think of
political,
demographic,
social, economic
and environmental
reasons.

6. Q6. In your groups discuss what the creator of this cartoon is trying to
say about the reasons why Metro Manila experiences such bad flood
problems? Try to create a detailed answer.

7. The graph below is a river hydrograph. It shows how river discharge (the
volume of water flowing in the river) is influenced by precipitation. The
graph shows 2 rivers (A and B).
Q7. Using the
Level at which River discharge table that you
river floods created in
activity 2 to help
you, create a list
Rainfall
of factors you
think could
explain the
differences
between the
way rivers A and
B respond to
precipitation?

8. Q8. In your notes explain which river is more likely to cause floods

9. Q9. Write 2 summary paragraphs explaining:
a) The reasons why floods happen
b) How river hydrographs are used