A circular swimming pool has a diameter of 16 m, the sides are 4 m high, and the depth of the water is 2.5 m. How much work (in Joules) is required to pump all of the water over the side? (The acceleration due to gravity is 9.8 m/s^2 and the density of water is 1000 kg/m^3.)

I keep getting 86000ish for an answer yet its not right, anyone have any method of solving this? Thanks