9. Theissen’s and Isohyetal Methods

Try these first

1. 1.

   What does the Theissen Polygon Method estimate?

   Hint

   Think about what we use to represent rainfall distribution.

2. 2.

   What is an isohyet?

   Hint

   Remember the prefix 'iso-' means same.

3. 3.

   What is the main advantage of the Isohyetal Method over Theissen's?

   • It's simpler
   • It accounts for spatial gradients
   • It requires fewer data points

   Hint

   Focus on what makes Isohyetal unique.

4. 4.

   True or False: The Theissen Polygon Method is the most accurate method for estimating areal rainfall.

   • True
   • False

   Hint

   Think about the limitations of geometric methods.

5. 5.

   Given three rain gauge stations in a region with varied rainfall, if gauge A recorded 2 inches, B 3 inches, and C 1 inch of rainfall, use the Theissen Polygon Method to calculate the average rainfall if the polygon areas are 10, 20, and 30 acres respectively.

   Hint

   Apply the area-weighting formula for rainfall.

6. 6.

   You are analyzing rainfall data across a mountainous region and need to create isohyets. Explain the procedure you would follow, considering spatial interpolation.

   Hint

   Focus on interpolation techniques and logical contour placement.