Water Lesson 5: River Regimes Flashcards
Define river regime
Annual variation in discharge of a river
How are river regimes measured?
Measured at a particular point or gauging station and is measured in cumecs
Name factors which affect river regimes
-Size of the river basin
-Amount, pattern and intensity of the precipitation
-Temperatures
-Geology
-Vegetation cover
-Human activities
Explain why the size of the river basin affects river regimes
Many large rivers have very complex regimes resulting from varied catchments
Explain why the amount, pattern and intensity of the precipitation affects river regimes
Regimes often reflect rainfall seasonal maxima or when the snow fields or glaciers melt - for snow the peak period is in Spring, for glaciers it’s early summer
Explain why temperatures affect river regimes
Evaporation will be marked in summer as the temperatures are warmer
Explain why geology and overlying soils affect river regimes
Permeability and porosity can affect this – water is stored as groundwater in permeable rocks and is gradually released into the river as base flow, which tends to regulate the flow during dry periods
Explain why vegetation cover affects river regimes
Wetlands can hold the water and release it very slowly into the system
Explain why human activities affect river regimes
E.g. dam building, can regulate flow
Length of Amazon river basin?
6308 km
Size of Amazon drainage basin?
6 million km2
Climate of the Amazon basin?
humid and tropical
Geology of Amazon basin?
River flows over an ancient Shield of rock, made up of igneous and metamorphic rock
What affects peak and low discharge of the Amazon basin?
Linked to the wet and dry seasons and snowmelt from the Andes
What process is high in the Amazon basin?
Evapotranspiration
