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Changes in Hydrological Cycle (Human factors affecting flooding (Hard…
Changes in Hydrological Cycle
Causes of Droughts
Meterological = long-term precipitation is lower than normal
Agricultural = circumstances when soil moisture is inefficient
Hydrological = occurs when there are deficiencies in water stores
Socio-economic = based on impacts of drought on supply and demand
El Nino event 2014-16
Included drought conditions in South America, and flooding in Australia
More tropical cyclones occurred in the Pacific, which limited hurricane activity in the Atlantic
60 million people face hunger as a direct result of ENSO in 2016
Indonesia has a severe drop in food production
La Nina event 2010-11
Caused Australia to have its wettest September on record in 2010
Brought California its wettest summer in 2011
North West Pacific saw 2011 being one of the coolest years, causing snow and rain mix in May
Tropical Drought in Rio 2014
Causes of drought
High pressure weather systems diverted rain further North away from the Amazon
Heavy rains occurred in Bolivia, whilst dry air remained over Brazil
Impacts of drought
Water rationing for 4 million people
Halting of HEP production leading to power cuts
Depletion of Brazil's 17 largest reservoirs
Increased groundwater abstraction - lower aquifers
Impact on Rainforest
Drought causes trees to die leaving less canopy cover
Reduces humidity, water vapour and rainfall
Exposed to sunlight causes vegetation to die
Making it vulnerable to wildfires
Impacts on Wetlands
Water drying up leading to less vegetation
Increased drying leading to soil erosion
Drought can eliminate species causing gaps in food web
Physical factors affecting flooding
Intense Heavy rainfall
Boscastle in 2004
75mm of rain fell in 2 hours
Debris blocked bridges and river broke their banks
Loss of tourism, which is 90% of industry
Damage to local ecosystem with uprooted trees
Mid-latitude depression
Hurricane Harvey
Monsoon
South East Asia 2017
ITCZ moved further north bringing rain to area
Blocked storm drains from rubbish
1200 people killed, 40 million affected
Marine life killed because of sewage contamination
Snowmelt
Human factors affecting flooding
Hard engineering
Deforestation - reduced interception
Animals - trampling soil
Urbanisation - impermeable surfaces
Vegetation removal
Drought case studies
Sahel Region
Climate warming means less water bearing winds are reaching the region
Land being over cultivated leading to desertification
Increased human vulnerability in the future
Millennium Drought Australia
Annual rainfall between 97 and 2009, 12% lower than 20th century mean
Increased cost to produce crops
Strict water restrictions were put in place
Ecosystems damaged because of limited vegetation
SouthWest America
Colorado provides water for 40 million people
Low snow pack in Rockies, leading to less water
Heat-related deaths in Arizona
Water from river supplies 1 in 10 Americans