Answer to Question #194621 in Civil and Environmental Engineering for Akinwande

Question

Compute the mean annual precipitation for the watershed in Figure Q2 using the arithmetic mean, 

Thiessen polygon method, and the isohyetal method. The gauge readings for gauges A -K, respectively 

are: 29.79, 34.97, 25.6, 24.2, 24.6, 42.61, 4 2.35, 1 5.51, 39.994, 3.04 and 28.41. 

Answer 1

Arithmetic method

Average rainfall=(29.79+34.97+25.6+24.2+24.6+42.61+ 42.35+15.51+39.994+3.04 + 28.41)/11

=28.27

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