Unit 1C - River Landscapes in the UK - Flood management strategies Flashcards
Difference between hard engineering and soft engineering?
Hard - man-made structures built to control flow of rivers and reduce flooding
Soft - schemes set up using knowledge of a river and its processes to reduce effects of flooding
4 soft engineering strategies?
Flood warnings and preparation, flood plain zoning, planting trees, river restoration
4 hard engineering strategies?
Dams and reservoirs, straightening meanders, embankments, flood relief channels
How do dams and reservoirs work?
Large barrier across river to stop its flow and artificial lake behind it flooding valley. Water released in control way through sluice gates so there should be no risk of flooding
4 +ves and 3 -ves of dams and reservoirs?
+ve: - no risk of flooding
- boosts tourism
- provides hydroelectric power
- new habitats for wildlife
- ve: - flooding of valley displaces people and can destroy habitats
- extremely expensive
- soils can become less fertile downstream as sediment trapped
How does straightening meanders work?
Meander straightened to reduce flood risk as water moved out of area more quickly
3 +ves and 4 -ves of straightening meanders?
+ve: - seriously reduces risk of flooding
- insurance costs in area fall and property prices rise
- can increase trade upstream as it is easier for ships to navigate
- ve: - when meets next meander, it can increase flood risk
- expensive
- may destroy habitats
- may have concrete lining which is very unattractive
How do embankments work?
Artificially raised river bank which sometimes are enforced with gabions. Allow water to rise to higher level without flooding
4 +ves and 4 -ves of embankments?
+ve: - can hold more water so less likely to flood
- provide habitat for animals
- often provide riverside paths as attractive walkway
- cheap compared to other hard strategies
- ve: - not as reliable as other hards
- harder for fishermen and boats to access river
- higher maintenance costs than other hards as constant monitoring and repair
- concrete lining may displaces animals
How do flood relief channels work?
Artificial channel designed as back-up channel for river that frequently floods. Runs next to original one and when river is at high flow, a gate closes off river channel and water diverted down and taken away to relief channel
4 +ves and 6 -ves of flood relief channels?
+ve: - removes flood risk
- calm water provides areas for boating and sidepath walks
- nature reserves can be set up in them
- insurance costs lower and house prices higher in area
- ve: - people living path of relief channel must be moved
- settlements downstream suffer from increased flooding
- expensive
- needs to be maintained and repaired
- long time to build
- destroys habitats and looks ugly
How do flood warnings and preparation work?
Environment Agency uses Met office weather data along with data on river levels to provide flood alert information, and provides a flood amp website, media publicise EA information. EA give information on how to prepare yourself for flooding
3 +ves and 3 -ves of flood warnings and preparation?
+ve: - cheap as largely dependent on communication via internet
- warnings in advance means people can protect valuables and evacuate
- ensures peoples safety without investing in expensive hards
- ve: - only effective if people listen to them and education needed
- doesn’t stop flooding so people in flood still at risk
- clearing up after flood is distressing and live in temporary accommodation
3 +ves and 3 -ves of flood plain zoning?
+ve: - impermeable surfaces aren’t increased, reducing flood risk
- low cost as only involves administration costs
- preserving natural environment means green space provided
- ve: - limited use as many cities have already built on them
- problem with house shortages in UK as limiting land
- doesn’t stop flooding just reduces risk
4 +ves and 3 -ves of planting trees?
+ve: - low cost as only have to pay for planting trees
- works with nature and reduces flood risk
- new habitats created
- more CO2 absorbed
- ve: - loss of potential grazing land
- changed appearance of area from open grass
- doesn’t stop flooding
