You fucked up your V value, 1.08/1000 = 0.00108m^3
Also you used the diameter instead of radius
The correct working is
A=n*1.8^2
=10.179
Volume of water = 216*0.005
=1.08m^3
1.08=10.179h
h = 10.6cm increase
I got 10.6cm as my answer but made 2 errors in my working for my exam where I mixed...