Hillslope water cycle Flashcards
What is the hillslope water cycle affected by?
- natural and human factors
- changes in stores over short timescale
- magnitude of stores change in response to a variety of processes
What are the factors affecting the hillslope water cycle?
- deforestation
- storm events
- seasonal change
- farming
- urbanisation
- water abstraction
What is a river regime?
the variability in a rivers discharge throughout the course of the year, in response to precipitation, temperature, evapotranspiration and drainage basin characteristics
How does deforestation lead to changes in the water cycle?
- removes water-absorbent forests which trap and transpire rainfall
- heavy machinery compacts soil decreasing infiltration
- less evapotranspiration/interception from tree canopy
- increased overland flow and throughflow - less friction from plants
- shorter lag time
extensive deforestation eg.in the Amazon leads to:
- reduced water vapour in the atmosphere due to decreased evapotranspiration - lower precipitation rates so river levels fall
How do farming practices affect the water cycle?
- livestock lead to the trampling and compaction of soil - lower infiltration capacity
- crops - increase infiltration and evapotranspiration - crops are dormant in late autumn/winter so overland flow is high
- irrigation techniques - more water in surface stores - higher rates of evaporation
- ploughing - aerates soil so increased infiltration capacity
- heavy machinery can compact soil - reduced infiltration
How does water abstraction affect the water cycle?
- taking water from a ground source
over-abstraction can lead to:
- rivers drying up
- damage to wetland ecosystems
- sinking water tables
How do storm events lead to changes in the water cycle?
- including flash floods and unexpected weather events
- intense rainstorms - less infiltration, more surface runoff and more flooding due to saturation of soil
How do seasonal changes lead to changes in the water cycle?
wet seasons - precipitation exceeds evapotranspiration leading to a water surplus. groundwater stores are full and more surface runoff results in higher discharge levels
dry seasons - precipitation lower than evapotranspiration and groundwater stores are depleted . Water used by humans and plants is not replaced so water deficit
What is river discharge?
the volume of water flowing through a river channel; measured at any given point in cubic metres per second.
