Question

 Compute the mean annual precipitation for the watershed in the figure for Problem 2.3 using the arithmetic mean and the Thiessen polygon method. The gauge readings for gauges A-K, respectively, are: 28.1, 33.7. 25.6. 23.9. 24.6. 40.7. 41.3.37.2. 38.7. 41.1, and 29.3

Answer 1

Arithmetic method

Average rainfall=$(28.1+33.7+25.6+23.9+24.6+40.7+41.3+37.2+38.7+41.1+29.3)/11$

=33.10

Thiessen polygon method

Rainfall =(P1A1+P2A2+P3A3+---)/(A1+A2+A3+----)

isohyetal method

(((P1+P2)/2)A1+((P2+P3)/2)A2+--)/(A1+A2+A3+----)

As the area is not given so not able to calculate