flooding and drought revision –

Flooding and drought

Revision –

see s-cool.co.uk A Level

Geography

Also – BBC Bitesize, and search for drought

Causes of floods6 causes – • global warming• deforestation • tsunamis• monsoon• ice melt• high drainage density• tides• urbanisation

Deforestation in detail – infiltration, transpiration, stem flow, runoff, soil enters river.

Flood hydrograph – what it shows, how it works

Effects of floodsPrimary effects• Physical damage – Can damage any type of structure, including bridges, cars,

buildings, sewerage systems, roadways, and canals.

Secondary effects• Water supplies – Contamination of water. Clean drinking water becomes scarce.• Diseases – Unhygienic conditions. Spread of water-borne diseases.• Crops and food supplies – Shortage of food crops can be caused due to loss of

entire harvest.[4] However, lowlands near rivers depend upon river silt deposited by floods in order to add nutrients to the local soil.

• Trees – Non-tolerant species can die from suffocation.[5]

• Transport - Transport links destroyed, so hard to get emergency aid to those who need it.

Tertiary/long-term effects• Economic – Economic hardship, due to: temporary decline in tourism, rebuilding

costs, food shortage leading to price increase, etc.

Solutions to flooding – small and large scale

• the creation of embankments (artificial levees) along the river to increase channel capacity and restrict flood waters - however since 1957, 7,500km of flood embankments have been constructed and yet many were breached in the 1998 floods;

• constructing flood protection shelters (large buildings raised above the ground) to shelter both people and animals

• emergency flood warning systems and plans made for organising rescue and relief services;

• providing emergency medical stores in villages• building flood proof storage sheds for grain and other food supplies• dam construction upstream and major embankments around Dhaka have been

suggested however lack of money has meant that these suggestions have not been taken further.

Case study: Bangladesh (see Geobytes)

Case study: Your country

Causes Effects Solutions

Causes of drought

3 causes

Effects of drought

3 effects

Solutions to drought

3 solutions

3 case studies

Place, date, causes and effects

Possible – Dustbowl, Philippines, Horn of Africa

Imageshttp://www.pupilvision.com/yeareleven/hydrograph.htm

http://geobytesgcse.blogspot.com/2006/12/flooding-in-ledc-1998-floods-in.html