Case studies for rivers - created from Mind Map

Mozambique Causes Effects Flood defences 3 days of heavy rain in January 5 weeks of continuous rain Cyclone Eline 22nd Feb Less grassland so less infiltration No flood area - being used for farming Urabanisation Causes water to flood in upper courses of river More than 1 mill homeless Thousands drowned Quick spread diseases in refugee camps Destroyed farmlands Repair costs 83% pop work in agriculture $30mill roads $6mill railways $4mill electric supplies Can't afford Able to start flood warnings due to funding from EU Can't control river as upper courses in other countries

Sheffield Causes Effects 1 months rain fell in one day on June 15th 2007 10cm fell on 25th June The confluence of several rivers Sheffield in a valley = surface run off Soil saturation The 10cm ran into lakes and rivers and surface runoff 2 rivers joined and one was already full - water backed up Banks overflow causing flooding Reservoirs filled up and flooded Flooded football stadium - 8 metres deep 43% houses flooded - 9 months to sort out People had temporary housing in caravans Sewage escaped into drinking water Dangerous situations - evacuated 400 people slept overnight in offices 23 airlifted to safety Tool making company had repair costs of £15mill Shopping centre badly flooded and stock lost Cost several mill to remove water Health risks

Preventing flooding in River Derwent - North Yorkshire Soft engineering Hard engineering Washlands between embankments and river Building restricted on floodplain Planting in catchment Reinforcing banks with woven willow to stop bank erosion and so the river doesn't get silted up Warning systems Data on rainfall Embankments Sluice gates upstream hold back water and let it out steadily Rural area and high value land - hard engineering isn't appropriate for the whole area Didn't prevent flood damage in 1999

The Sahel - desertification Causes Effects Overgrazing Farming of average land Destruction of plants in dry regions Normally rains 1-2 months a year Rainfall been below average since 1970 - some years 25% less When it does rain - surface runoff  Other years there is no rain at all  rivers dry up  water table falls  farmers crops fail  animals die  desertification  decreased food supplies  famine Soil becomes less usable Lack/damage of vegetation Famine Food loss People near affected area

Colorado dam Regulates river flow Creating resevoirs Trap sediment behind dam Costs Benefits Less energy left to move sediments Which keeps water warm for fish Less flood risks - flood peaks smoothed out Costs Benefits Loss of land flooded by reservoir Regular all-year water supplied for cities like Las Vegas Costs Benefits Shrinking sandbanks means some animals lose habitat and tourists lose rafting /

Water stress Lake Chad South East England Sonoran desert Australia One of largest lakes in world Supports over 20mill people Global warming is evaporating lake Lack of rain People need lake for fishing, drinking and farming Dry winters so reservoirs didn't fill up Last Jan only 2/3 of annual monthly rainfall Hose pipe bans High pop and low precipitation 2011 farmers lost out on crops In 30 years there will be bad drought if nothing is done One farmer lost £20,000 due to spring drought Uses of water Why rate is increasing Impact Supply pop demand Water features Farms Pop increasing 1.8 - 3.6 mill Urbanisation Water supply not sustainable Water quality deteriorating Expensive Water table falling 3m in ayear Building canals-destroying habitat Ground giving way

Dhaka, Bangladesh slum on disused railway station. No safe water or toilets  WaterAid constructed 6 tube wells and 2 new sanitation blocks people are no longer continually ill they can run facilities themselves moving out of poverty

Case studies for rivers