Case Studies

Question 1

Waterfall Case study

Answer 1

Niagra Falls
-flows for 50 km between lake erie and lake ontario
-falls 108 m
-flows in 2km wide channel and then into narrow 400m wide and 11km long gorge
-course established 12 000 yrs ago
-Lake Erie began to spill over lake ontario and in doing so passed over higly resistant rock (limestone)
-rate of retreat (1 m PER YR)
in 1900s rates of recession wete higher 1.2m but have been reduced as the amount o water flowing is reduced (hydro-electric power stations)
- parts of rock reinforced in 1960s

Question 2

Delta Case study

Answer 2

Nile delta
-facing costal erosion at up to 100m per year
-arcuate delta
-Bird’s Foot Delta: The Mississippi Delta (USA)
Cuspate Delta: Niger Delta (Nigeria)
Arcuate Delta: Nile Delta (Egypt)

Question 3

Flooding

Answer 3

Bangladesh
Location- Where Ganges Jamuna and Meghna rivers meet
Stats- area of 150 000km shared by 123 mil people dependent on agriculture
Rivers - two of largest rivers by catchment size length and sediment discharge Ganges carries 520 mil tons of sediment

Causes of flooding
-HIMALAYAS-source of ganga and many springs which feed into jamuna
-heavy moonsoon rains
-heavy river discharge
-deforestation
-glacial melt

INDIAN PLAINS-
-High river discharge
-heavy rain

Bangladesh floodplaim
-flat topography
-low gradient channel
-rising of sea level

1998 FLOODS
causes-high peaks of 3 rivers at same time
-high tides
-strong moonsoon

COPING
-houses and roads built on aised platforms
-bamboo used for on islands
-crops cultivated which can survive submergence- sugar cane, rice
FLOOD ACTION PLAN OF 1989-95 development of bangladesh water and flood management strategy
MINIMUM-improve forecasting and existing flood schemes but dont produce new ones
- selective- protect densely populated areas
major- large scale engineering works 100000 km of levees

780-1500 deaths during floods
many families forced to move 10-15 times in their life