Flood hydrograph

• Features to flashy hydrographs:

  • Short lag time
  • Steep rising and falling limb
  • Higher flood risk
  • High Peak discharge
• Features to a subdued hydrographs:

  • Long lag time
  • Gradually rising and falling limb
  • Lower flood risk
  • Lower peak discharge
• A hydrograph is used to represent rainfall for the drainage basin of a river and the discharge of the same river on graph
• Flashy Hydrograph

  
• River discharge = the river discharge measures the amount (volume) of water passing through the river channel at any one time. If the discharge of a river is particularly high, it can mean that the water has passed over the banks resulting in a flood.
• Rising limb = the rising limb is an indicator of the speed of the river reacting to a storm event. For example, if the gradient of the rising limb is steep, then the river responds quickly, and if the gradient is less steep, it responds more slowly.
• Baseflow = the base flow refers to the amount of water in the river ordinarily (i.e. even without the storm event). The base flow can charge depending on the time of year and the surrounding climatic and drainage basin conditions.