Page 39 - Year 10

Geography: 4 of 5 Geography: 5 of 5

River Management Strategies
Boscastle, Cornwall Flood August 2004
Hard Engineering
Factors affecting flooding Flash flood caused millions of pounds of damage and disrupted tourism. In response the old bridge was replaced by a taller one to allow
Strategy Benefits Costs debris to pass under, the river channel was deepened and widened, the embankment was strengthened, a flood wall was built, dead
Physical Human
Dams & Reservoirs– • Can be used for HEP or • V expensive (Kielder dam cost £167 million) trees and vegetation were removed, the car park was raised and a gauge was installed to monitor water levels
• Precipitation • Farming Concrete dams control tourism • Social costs of displacement
• Geology • Urbanisation river flow by creating • Creates new wetland • Reservoirs silt up Social Issues Economic Issues Environmental issues
• Relief • Deforestation artificial reservoir habitats • Can lead to conflict over
• Creates source of water rights eg Nile • Residents lives disrupted during building of new • Homes and businesses less at risk of • Vegetation in river habitats
defences
drinking water monitored and biodiversity
• V effective • Many residents think new bridge is ugly and not flooding improved
in keeping with village • Scheme cost over £4 million. Some • New channel has been engineered
Channel Straightening – • Insurance premiums • Lead to flooding downstream • Safer idea rejected on basis of cost to look natural
water flows out of area may fall • High maintenance • Will protect against a 1 in 75 year flood only
faster • Effective • unattractive
• Navigation improved
Embankments – • Increased capacity for • Expensive
artificially raised using carrying water • Looks artificial
concrete to • Creates walkways • More serious flooding if embankment fails
deepen channel (eg London) (New Orleans)
• New river bank habitats

Flood Relief Channels – • Opportunities for • V expensive – Jubilee River cost £110
new channels to by pass recreation (fishing and million)
towns walking) • Regular maintenance needed
• New aquatic habitats • Habitats disturbed
creates
• Insurance premiums
reduced

Soft Engineering
Flood Warnings. - • Sustainable • People may not respond
monitoring rivers to allow • Low cost • Need for
floods to be predicted • Focus on helping people monitoring equipment

Floodplain Zoning – • Low cost • Restricts
not building in flood areas • Conserves water meadows economic development
for recreation and wildlife • Housing shortage
• Hard to
implement retrospectively
Planting trees – Trees • Crates habitats • Loss of farmland
increase interception and • Natural • Loss of economic use of land
slow flooding • Low cost • Not totally effective