Answer
The gauge pressure should be $1.6\times 10^5~N/m^2$
Work Step by Step
We can use Bernoulli's equation to find the gauge pressure required for the water to reach a height $h_2$ of 16 meters. Note that the water speed on both sides of the equation is zero so we can leave it out of the equation.
$P_1+\rho~g~h_1 = P_2 + \rho~g~h_2$
$P_0+P_G+\rho~g~(0) = P_0 + \rho~g~h_2$
$P_G = \rho~g~h_2$
$P_G = (1000~kg/m^3)(9.80~m/s^2)(16~m)$
$P_G = 1.6\times 10^5~N/m^2$
The gauge pressure should be $1.6\times 10^5~N/m^2$.
