Page 37 - Year 10 Knowledge Organiser

Geography: 4 of 5 Geography: 5 of 5

River Management Strategies

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