WATER CASE STUDIES Flashcards
What caused the 2014-15 brazil drought?
Usually, rainfall in brazil comes from the south Atlantic across the brazil basin but in 2014/15 a series of high-pressure systems diverted them north resulting in dry air for Brazil and heavy rain in bolivia.
What were the impacts of the 2014/15 drought?
> Said to be brazils worst drought: water rationing for 4 million people; water supplies cut off for 3 days a week in some towns.
Halted HEP production causing power cuts.
Dangerously low levels of reservoirs (some down to 1%) and depletion of aquifers
coffee bean reduced so prices pushed up to 50% globally.
What were the human actions as a response to the drought?
Farmers and industries increasingly used groundwater as rivers had low levels of water. This became the only water source for many urban poor and remote rural areas.
>due to the high fees of 3000$ to have a license and the high expenses of running a well 35K- 100K in $ many people instead opted for illegal wells, shrinking groundwater levels.
>Illegal wells were shallower and less filtered by bedrock containing industrial polutants and higher levels of bacteria.
What were the impacts of drought on rainforest ecosystem?
Amazon referred to as the earths lungs, its 400 billion trees transport humidity inland from the Atlantic ocean taking 20 billion tonnes of water vapour daily from the forest and dumping it as rain on central and southern brazil. Amazon river carries 17 billion tonnes of water to the Atlantic every day.
Prolonged drought causes forest stress and sets up cahin reaction where younger trees die reducing canopy cover and therefore humidity ,water vapour and rainfall.
>With less tree cover exposed to sunlight litter and dying vegetation creates forest fires causing die back.
what are the impacts of drought on wetland ecosystem in particular the pantanal?
> The Pantanal is a large wetland area in central south America, 14000 km2 of which lie within brazil making it the most significant wetland ecosystem home to many rare species and birds.
> Seasonally flooded between april & nov. Flooding covers 80% of Pantanal & wetlands retain 60% of freshwater throughout the year.
> In 2014/15 drought tree mortality was increased reducing habitats for wild animals/ cattle and ecotourism
> wildfires became a major threat caused by ranchers burning old grass to clear vegetation.However these became an uncontrolled inferno, burning wetlands and forests.
Where in the UK is rain most common and why?
Northwest of the uk, combination of warm wet westerly winds-plus uplands such as the Cumbrian fells- creates orographic rainfall resulting in places such as cumbria being wettest places in england.
What was storm desmond created by?
Caused by deep alantic low pressure systems bringing prolonged and heavy rainfall through a ‘warm conveyor belt’
What were the immediate effects of storm desmond?
> Honister pass recorded 341.4mm of rain in just 24h
> 405mm of rain fell in Thirlmere in 38 hours.
> 5200 homes were flooded.
> Major roads and rail services were disrupted for several days
> landslide closed a section of the West Coast mainline between Preston and Carllisle.
> 61000 homes lost power when an electrical substation was flooded
where was the worst affected and What caused the flooding in storm desmond?
Major disruption, with the greatest impacts due to flooding. Carlisle was worst hit by severe flooding from the river Eden.
December flooding worsened by the already saturated ground- had been the second wettest month since 1910.
This wetness can be explained by the position of the jet stream. Driving force which determines the direction of depressions and their speed of movement this band of air remained on the Uk for longer than usual bringing in rainladen depressions from the Atlantic.
What physical factors caused the flooding in cumbria?
> Moist air mass stayed up over Cumbria for 48 hours- delivering record rain.
> cumbrian fells created orographic rainfall
> conyeyor of warm and moist air shifted towards to the UK from the Caribbean where sea temps were unusually high.
> too much rain for the already saturated ground to absorb. Overland flow carried water to rivers where it overflowed. Steep slopes accelerated this process.
> Impermable surfaces and sewers/drains blocked by debris, mean surface water flowed rapidly and directly into the already-overfilled river channels.
What were the long term ESE impacts of 2015 flooding in cumbria?
SOCIAL:
>5200 homes flooded –>leading to temporary accommodation
>local services such as schools had to close and many residents suffered phycological trauma
ECONOMIC:
>Many businesses closed, transport for infrastructure damaged
>cost of cumbria flooding was 100 million in 2005
>insurance claims caused by flooding exceeded 6 £ billion
>Houses prices fell and tourism was deterred.
ENVIROMENTAL:
>many river banks eroded, adding to flood risks with them full of debris and contaminated with sewage effluents/pollutants.
>soils eroded, habitats destroyed , with saturated ground leading to decomposition of dead animals giving off noxious gases poisoning ecosystems and saturated ground also caused landslides.
How has the Sahel been affected by climate change?
Variable rainfall in the Sahel region where rain varies from 100mm to 600mm per year. Up to 90% in the summer, as part of the West African monsoon.
> from 1970s to the 1980s rains faced decline of rainfall of up to 40%.
> sahels climate changing since 1996 as several wet years have persisted, offering the ability to convert dry landscapes to productive farmland.
> Re-greening is a restoration technique that involves planting trees and bushes, helping farmers benefit from increased yields, natural regeneration of water-retaining shrubs and low-cost foresting, and water-harvesting techniques.
How has the Sahel been affected by climate change?
Variable rainfall in the Sahel region where rain varies from 100mm to 600mm per year. Up to 90% in the summer, as part of the West African monsoon.
> from 1970s to the 1980s rains faced decline of rainfall of up to 40%.
> sahels climate changing since 1996 as several wet years have persisted, offering the ability to convert dry landscapes to productive farmland.
> Re-greening is a restoration technique that involves planting trees and bushes, helping farmers benefit from increased yields, natural regeneration of water retaining shrubs and low-cost foresting, and water-harvesting techniques.
How has the Sahel been affected by climate change?
Variable rainfall in the Sahel region where rain varies from 100mm to 600mm per year. Up to 90% in the summer, as part of the West African monsoon.
> from 1970s to the 1980s rains faced decline of rainfall of up to 40%.
> sahels climate changing since 1996 as several wet years have persisted, offering the ability to convert dry landscapes to productive farmland.
> Re-greening is a restoration technique that involves planting trees and bushes, helping farmers benefit from increased yields, natural regeneration of water-retaining shrubs and low-cost foresting, and water-harvesting techniques.
How has the Sahel been affected by climate change?
Variable rainfall in the Sahel region where rain varies from 100mm to 600mm per year. Up to 90% in the summer, as part of the West African monsoon.
> from 1970s to the 1980s rains faced decline of rainfall of up to 40%.
> sahels climate changing since 1996 as several wet years have persisted, offering the ability to convert dry landscapes to productive farmland.
> Re-greening is a restoration technique that involves planting trees and bushes, helping farmers benefit from increased yields, natural regeneration of water-retaining shrubs and low-cost foresting, and water-harvesting techniques.
