What are the interceptions and subsequent evapotranspiration levels like in the Amazon?
High due to dense canopy cover
How does water input into the Amazon basin?
- Thin soil in Tropical Rainforest above impermeable clay so high surface ruhn-off, limited infiltration
- Water flows into the ‘Whitewater’ Amazon River
How does water get into GW storage in the Amazon?
Some carbonate rocks allow percolation into deep GW storage - flows as Rio Hamza 4KM deep
What are the 2 major tributaries of the Nile?
The White Nile and the Blue Nile
How does climate influence the Nile?
Precipitation north of Sudan <20mm, channel flow very small
How does vegetation influence the Nile?
- Provides Egypt with its only vegetation
- Vegetation density increases as you move south into wet highlands (closer to ITCZ) = higher interception + evapotranspiration in summer monsoon months
How does topography/relief influence the Nile?
Steep topography in Ethiopian Highlands = SRO + high levels of mechanical weathering at altitude = erosion of dark top soil (Blue Nile)
How does geology influence the Nile?
Ethiopia - largely volcanic rock - but highly permeable due to weathering
What are the human vulnerabilities with the Nile?
Egypt holds and controls most water (reliable channel flow) BUT Ethiopia currently building Grand Renaissance Dam - threatens water security for Egypt - 90% of Egypt’s water comes from Blue Nile’s summer floods
Rockies Mountains
- Watershed for Colorado Basin (West) and The Great Plains Basin (East)
- Ogallala Aquifer (underneath Great Plains) is confined, has caliche layer preventing infiltration
- Rural electrification, wheat production etc extract water from Ogallala Aquifer
- People trying to recyle water, planting crops that need less water
Yukon river regime
- Comparable to Siberian rivers due to sub-arctic latitude
- Sections of river freeze over during winter months
- Permafrost discontinous over its course (50-90% coverage) - inhibits percolation but melting can = flashy regime
Amazon river regime
- Varies between equatorial (with no dry season + heavy convectional rainfall all year) and tropical river regime (with drier season in winter due to northward migration of ITCZ)
- Highest flow after summer rainfall peak
- Laterite clays = larger channel flows over whole basin
Nile river regime
- Tropical with distinct drier season - no rainfall at all in northern margins = negative water balance
- Ethiopian Highlands has impermeable geology (volcanic rock, dark soil) = large amounts of runoff transferred downstream (Blue surface soil)
- Peak discharge in summer months - summer monsoon relief rainfall = spikier regime, then rapid fall due to high evapotranspiration rates
