Flood management (soft)

Question 1

Afforestation

Answer 1

Increases interception – slows passage of water to river channel. Increased evaporation of intercepted water and transpiration (via root uptake), so less water reaches the channel.

Takes time to put in place. Significant afforestation has taken place in the upper Tennessee Valley (Mississippi tributary)

Question 2

Contour ploughing + strip farming

Answer 2

Practiced in semi-arid areas (e.g. Sahel). Fields are ploughed parallel to contours, following shape of land. Furrows at right angles to contours (i.e. running straight downslope) act as effective channels for run-off. Reduced amounts of surface run-off and therefore flood risk

Question 3

Floodplain zoning

Answer 3

Determining land use with the flood risk in mind. Vulnerable areas used for grazing and leisure (low value). For example, Port Meadow in Oxford, a 440 acre area of Thames floodplain just to the north of the city centre. Doesn’t prevent but limits damage.

Question 4

River restoration schemes

Answer 4

Compromise between sustainable environmental gain and economic considerations. Recognises that a functional floodplain, as long as it remains undeveloped, is a useful flood protection device for downstream sites.
An example of this includes the ‘Quaggy Flood Alleviation Scheme’ in Greenwich

Question 5

Wetland conservation schemes

Answer 5

Wetlands are natural sponges. Many have been drained. The Mississippi Wetland Conservation Scheme on the Mississippi River aims to improve water quality, enhance habitat and species diversity, reduce soil and erosion and reduce flooding.

Question 6

Forecasting

Answer 6

Environment Agency now issues flood warnings (Flood Watch-Flood Warning-Severe Flood Warning-All Clear) which are broadcast on the BBC weather forecasts. Doesn’t prevent but limits damage.