Chapter 2: Precipitation (Part 2)

Moving average is used to show ...

• The errors in rainfall data

• The trend of rainfall

• The highest rainfall in the year

• The lowest rainfall in the year

To calculate the mean precipitation over an area, the following method can be used EXCEPT ...

• Thiessen mean method

• Isohyetal method

• Arithmetic mean method

• Geometric mean method

The difference between the Thiessen mean and Isohyetal methods are stated below EXCEPT ...

• Thiessen method assigns weightage to the rainfall based on polygons

• Isohyetal method assigns weightage to the rainfall based on dividing lines

• Isohyetal method is used when measured rainfall show little variation

• Thiessen method includes stations located outside of the catchment in the rainfall weightage

Theissen polygons are generated by first drawing the lines connecting the stations. Next, ...

• Two points in each connecting line is located and removed.

• The lines connecting stations outside of the catchment are removed.

Isohyets are lines that has ...

• equal cumulative rainfall

• equal rainfall intensity

• equal rainfall magnitude

• equal rainfall hyetograph

• return period

• recession period

• rising period

• relocation period

• 10 years

• 20 years

• 25 years

• 50 years

• will occur at least half the time

• will occur at least twice

• will not occur at all

• will occur at least once

• will not happen at all

• will happen at least half the time

• will happen at least once

• will happen at least twice