27.6. Infiltration Indices

Try these first

1. 1.

   Define φ-Index.

   Hint

   Think about the conditions under which runoff is initiated.

2. 2.

   What does W-Index account for?

   Hint

   Consider what happens to rainwater before it contributes to runoff.

3. 3.

   What does the φ-Index represent?

   • A constant infiltration rate
   • Rainfall rate when runoff starts
   • Total rainfall amount

   Hint

   Think about how rainfall affects runoff initiation.

4. 4.

   The W-Index accounts for initial moisture losses. True or False?

   • True
   • False

   Hint

   Recall the purpose of using W-Index.

5. 5.

   During a heavy rain event, the total precipitation measured 100 mm, with a runoff of 30 mm after 5 hours. Calculate φ and W indices and discuss the implications of your findings.

   Hint

   Apply the formulas and interpret the findings in the context of hydrology.

6. 6.

   A scenario describes a storm with 70 mm of rain, but saturation means only 20 mm is effectively utilized for infiltration with runoff measured at 10 mm. Calculate the W and Wᵐᶦⁿ indices, explaining the environmental conditions leading to those values.

   Hint

   Make sure to consider how factors like saturation impact infiltration metrics.