Catchment Hydrology Flashcards
What impacts the flashiness of a catchment?
- Drainage basin shape
- Drainage density
- Land use
What is the water balance?
water input (precipitation) = water output - changes in water storage
How can you measure precipitation?
- Rain gauges
- Thiessen polygons
How do you measure evaporation.
- Atmometer
- Measures evaporation by monitoring loss of water from a porous surface
What is an atmometer?
- Measures evaporation by monitoring loss of water from a porous surface
How do you measure evapotranspiration?
- Lysimeter
- measures potential evapotranspiration by monitoring the weight of a isolated patch of vegitation with an unlimited water supply.
What is the equation for working out river discharge?
Discharge = area x velocity
Name 2 ways of measuring river discharge?
- Acoustic gauging
2. V-notch
What is an acoustic gauge?
gauges record time it takes for a sound to travel across a river at different depths
What is the discharge of the river Thames?
65 m3 s-1
What is the discharge of the rive Amazon?
175,000 m3 s-1
How is soil water content measured?
Loss of weight when heated/ electronic meter
How is ground water measured?
- Changing levels in wells
- measuring rock porosity
Define matrix flow.
Flow through the matrix of a soil
Define macropore flow.
Flow through connected pores less than 0.1mm in diameter
Define pipeflow.
Natural conduits formed in the soil greater than 1mm in diameter
What is the unit of measurement for runoff?
Cumecs (cubic metres per second)
What does a hydrograph do?
- shows how a river is affected by a storm
- discharge patterns of a bsin
What is lag time?
Time it takes for water to reach the river. This is affected by;
- infiltration
- run-off
