Floods and the Thames

Question 1

what is a flood

Answer 1

An overflowing of water on an area that is normally dry. Overwhelming amounts of water.

Question 2

4 causes of floods

Answer 2

Storm surge, snow melting, damn failing, tsunamis.

Question 3

what percent of natural disasters are caused by floods

Answer 3

40%

Question 4

2 major places where floods occur

Answer 4

Stream channels and Sea Coasts

Question 5

what is it common to occur in dry stream channels

Answer 5

flash flooding

Question 6

two different states of a stream channel

Answer 6

dry or active

Question 7

what is good about floods from stream channels

Answer 7

they deposit sediments from the river bed, adding nutrients to the soil, great for farming.

Question 8

what is a trash line

Answer 8

a line of debris of material left from levels of flooding..

Question 9

what are the strongest cause of flooding at sea coasts

Answer 9

tsunami

Question 10

what causes tsunamis that can cause flooding from coastal areas

Answer 10

earthquakes, landslides, volcanoes, or meteorite strikes.

Question 11

what are the two main causes of floods at sea coasts

Answer 11

tsunami and storm surges

Question 12

how are storm surges causes

Answer 12

elevation increase in the ocean caused by a low-pressure zone on the surface of the ocean, which is pulled along to the coast by the wind.

Question 13

total volume of the water on Earth is contained in rivers,

Answer 13

0.0001%. (.31s)

Question 14

total percent of water stored in oceans

Answer 14

97.25%

Question 15

total percent of water kept in ice caps and glaciers

Answer 15

2.05%

Question 16

how to rivers play a large role in the world’s ecosystem

Answer 16

they shape landscapes

Question 17

When rivers move from high to low ground, what happens

Answer 17

the solar and kinetic potential energy is converted into kinetic energy

Question 18

what is stream velocity

Answer 18

the distance travelled by a river in a given time, it is measured in metres per second.

Question 19

what is the range in stream velocity

Answer 19

0.2 ms-1 to over 10 ms -1.

Question 20

3 factors that influence stream velocity

Answer 20

channel gradient, location of water within the channel, stream bed texture

Question 21

how is river discharge calculated

Answer 21

width x river depth x river velocity

Question 22

what is the unit of river discharge

Answer 22

m3s-1

Question 23

what is river discharge

Answer 23

The discharge is the total volume of water that passes a plane perpendicular to a river in a unit time.

Question 24

what is river discharge influenced by

Answer 24

• the area of a drainage basin,
• topography of the basin,
• how much water is infiltrated, -
• total volume of water from precipitation,
• snowpack.

Question 25

range of river discharge

Answer 25

5m3s-1 to over 200,000m3s-1

Question 26

how do you measure discharge

Answer 26

To measure discharge, a gauging station can be used in an area calibrated to the height of the river.

Question 27

what is flooding actually caused by in a river channel q

Answer 27

Flooding is caused when river runoff is greater than infiltration.

Question 28

on average, how often do floods occur in an unaltered river system

Answer 28

Floods occur on average 1.5-3 years in an unaltered river system.