27.6.2. W-Index

Try these first

1. 1.

   What does the W-Index measure?

   Hint

   Think about what happens to rainfall before it contributes to runoff.

2. 2.

   What does 'initial losses' refer to?

   Hint

   Consider how vegetation affects precipitation.

3. 3.

   What is the formula for calculating the W-Index?

   Hint

   Recall the components involved in runoff estimation.

4. 4.

   True or False: The W-Index is less accurate than the φ-Index.

   • True
   • False

   Hint

   Think about what each index accounts for.

5. 5.

   During a storm, urban area P records total precipitation of 150 mm, with initial losses of 50 mm, resulting in 60 mm of runoff over a duration of 6 hr. Calculate the W-Index and discuss how it could affect city planning.

   Hint

   Understand that high runoff could lead to flooding if the drainage isn't adequate.

6. 6.

   In a rural area with P = 80 mm, initial losses of 10 mm, and Q = 20 mm, how does the W-Index compare to urban settings? Evaluate the implications.

   Hint

   Think about how infiltration may vary greatly between urban and rural contexts.