Drainage basin

• What are the main components of the basic system in fluvial environments?

  Inputs, Stores, and Outputs
• What is a closed system in the context of fluvial environments?

  A closed system has inputs and outputs of energy but not matter
• Give an example of a closed system.

  The Global Hydrological Cycle
• What characterizes an open system in fluvial environments?

  An open system has inputs, processes, and outputs of both energy and matter
• What is an example of an open system?

  The Drainage Basin System
• How does water enter and leave the drainage basin system?

  Water enters as input from the atmosphere and leaves to the ocean or atmosphere
• What are the inputs in the drainage basin system?

  • Mainly rainfall and snowfall
  • Water fills water bodies
  • Governed by transportation and external factors
• What is the average amount of precipitation in mountain regions?

  Greater than 2000 mm/year
• What factors affect spatial variations in precipitation?

  Geographical features like mountains and proximity to the sea
• How do temporal variations affect river regimes?

  Seasonality and frequency of rainfall influence river flow
• What is interception in the context of precipitation?

  Interception is when raindrops fall on vegetation before reaching the ground
• What factors influence interception by vegetation?

  The density of stems and the character of leaves
• What happens if rainfall exceeds the interception amount?

  Water will transfer to the ground surface or flow down the trunks
• What is infiltration capacity?

  The speed at which water can pass through soil particles
• What factors can affect infiltration rates?

  The soil type and the nature of the soil surface
• What is percolation in the context of water movement?

  Percolation is the movement of water through the soil column
• What is the water table?

  The upper limit of the zone of saturation
• What is the zone of saturation?

  The zone where all pore spaces are filled with water
• How is groundwater storage created?

  Through the constant movement of water via percolation
• What are the main outputs from the drainage basin system?

  • Water leaves via evaporation
  • Water leaves as channel flow
  • Water is transferred through various flows
• What is evaporation?

  The process where liquid water changes to gas and returns to the atmosphere
• What factors influence the rate of evaporation?

  Temperature, wind speed, relative humidity, and hours of sunshine
• What is transpiration?

  A biological process where water is lost from a plant through stomata
• What distinguishes potential evapotranspiration from actual evapotranspiration?

  Potential evapotranspiration is the maximum possible, while actual is what occurs
• How is sediment added to the drainage basin system?

  Through erosion of the surrounding valley and river channel
• What factors affect sediment yield in rivers?

  Vegetation, climate, geology, and human activity
• What are the consequences of too much sediment in a river?

  It reduces channel capacity and water quality
• How can human activity affect sediment yield?

  Deforestation and mining increase yields, while soil management decreases them
• What are the effects of sediment on river systems?

  • Reduces channel capacity
  • Increases flood risk
  • Lowers water quality for use
  • Affects stream ecosystems