$54$ Engineering Hydrology

Fig. $2\mathrm{.}25$ Problem $2\mathrm{.}9$

Hint: In the US National Weather Service $($USNWS$)$ method the weightage to the

stations are inversely proportional to the square of the distance of the station from the

station $M.$ If the co$-$ordinate of any station is $(x,y)$ then $D^2=x^2+y^2$ and weightage

$W=\frac{1}{D^2}.$ Then rainfall at $[$:$M=P_m=\frac{PW}{W}$