Case Studies

Question 1

River management scheme

Answer 1

The Mississippi, USA

1. Hard engineering
   - raised levees built 15m high over 3000km along river
   Partly to blame for 2001 floods they protect area they are built but push problem downstream

• over 100 days built on tributaries
  Dams trap silt preventing it from reaching the delta so birds like heron are endangered there or for enriching farm land so more fertiliser has to be used
• engineers cut through meanders to straighten 1750km of river channel to make river flow faster
  Straightened river loses variety of habitats for fish, plants & insects
  River erodes its banks to resume natural meandering course so money and time have been wasted

2. Soft engineering

• afforestation in Tennessee valley
  Prevents water reaching river by absorbing it, reduces soil erosion, provides wildlife habitats and opportunities for recreation
• safe flooding zones, houses near river are bought and demolished e.g rock island Illinois and areas of floodplain are turned into green space
  Cheaper in long term to prevent property damage than compensate owners when damage had happened. Wetland habitats close to river can be preserved

Question 2

Coastal management in British Isles

Answer 2

Newcastle, co. Down

1. Groynes - concrete, 1980s
   Impact - trapped sand moving north east, lasted 20 years then decayed becoming useless
   Sustainability- yes protected beach resulting in tourist enjoyment, no did not last long have to be replaced expensive
2. Gabions - wire mesh boxes filled w local stone placed near mouth of river shimna 2006
   Impact - protect recreation ground, stabilised area of coast to allow pedestrians use of footbridge to access rest of promenade , earlier gabions decayed and had to be replaced
   Sustainability- S, maintains important tourist attraction, S, break up wave energy better than other methods and have been successful, US, need to be replaced expensive
3. Sea wall - originally built in late 1800s replaced in 2002
   Impact - original wall protected buildings for many years, storm in 2002 washed parts away, new wall curved to direct wave energy back to sea instead of attacking base of wall, reflected waves increasing erosion of beach on way back

Sustainability - S, original allowed development of buildings and protected them for long time, U, expensive to replace new wall cost £4 million, U, if beach is eroded it cannot protect coast behind, fewer tourists will enjoy Newcastle so bring less money , U, wall caused erosion of beach

Question 3

Effects of climate change on MEDC

Answer 3

Positive

• warmer summers in southern England, more tourism such as £1.5 billion spent by tourists in July 1995
• farmers could grow more potatoes, tomatoes, vines and maize

Negative

• increase in pests like aphids and diseases in crops
• tropical diseases such as malaria
• some animals could become extinct

Question 4

Earthquake in British Isles

Answer 4

Causes

- many rocks in British Isles have faults or cracks

Question 5

Causes of flooding

Answer 5

River Derwent - March 1999

1. Physical causes
   - heavy rainfall over north York moors, 250mm in 12 days as much as usually falls in 3/4 months
   - ground in drainage basin was already saturated from previous rainfall so could hold no more water
2. Human causes
   - the peat of the north York moors used to store water like a sponge for days before releasing it to rivers but people had cut and removed lots of peat
   - houses have been built on floodplain e.g at Malton, making the ground impermeable from Tarmac increasing surface run-off