Lesson 4 - Water Budgets & River Systems Flashcards
What is a water budget?
The annual balance between inputs (precipitation) and outputs (evapotranspiration and channel flow).
What do water budgets show?
A direct comparison of natural water supply and demand, making it possible to identify time periods when precipitation exceeds evapotranspiration or times when there is a negative water balance and an increased drought risk.
What is a soil moisture budget?
A sub system of the catchment water balance. It too shows us annual changes in precipitation and potential evapotranspiration.
What is a river regime?
The annual variation in discharge or flow of a river at a particular point usually measured in cumecs.
What effects river regimes?
Human activities in the drainage basin.
What is the regime of the River Nile? (2)
The regime was changed significantly by the construction of the Aswan Dam in 1970.
The flow of the Nile was reduced by about 65% and became regulated by between the seasons so the flood peaks in September were greatly reduced.
What is the regime of the Amazon river? (4)
Humid tropical climate and flows over Shield area of rock.
Peak discharge is April - May.
Lowest discharge is in September.
Both of these are linked to wet and dry seasons and snow melt from the Andes.
What is the regime of the Yukon River? (3)
Tundra climate and flows through the mountains.
Peak discharge is in May-June with a dramatic increase due to melting of snow and ice.
Discharge is low from December to May due to low precipitation and frozen conditions.
