Theory question 207
Environmental Hazards and ConservationWrite explanatory notes on flooding under the following: (a) areas of occurrence; (b) causes; (c) negative effects; (d) control.
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Flooding is the covering of normally dry land by water.
(a) River floodplains and valleys (Niger, Benue, Nile, Mississippi); deltas and coastal lowlands (Niger Delta, Lagos, Bangladesh); low-lying parts of towns with poor drainage; areas below dams.
(b) Heavy and prolonged rainfall; overflowing rivers; release of water from dams; blocked drainage and building on waterways; deforestation increasing runoff; storm surges and high tides; melting snow; dam failure.
(c) Loss of lives; destruction of homes, roads and bridges; crops and livestock destroyed; displacement of people; water-borne diseases; soil erosion; economic losses.
(d) Build dams and reservoirs; levees and embankments; dredging and channelisation; good drainage and clearing of gutters; afforestation; control of building on floodplains; early warning; planned release of dam water.
Write points under all four headings.