Can water landing be simulated? Is is possible for a flight simulator software to simulate the real time scenario of landing an aircraft on a water body. There are instances of this (Ethiopian Airlines Flight 961, US Airways Flight 1549) and the results were catastrophic/great  based on the type of water body they landed on and the situation which brought them there and several other parameters. 

But I want to know if it is possible for a complex computer program to create this scenario effectively and thereby better equip the pilot ?
Technically yes, but I do not know of any simulator which includes this. The water forces can be calculated in the same way as the air forces, so I see no reason why it should't be possible.

Historically, model tests were made to check that a new airplane would behave well when landing on water. The simplest tests would use a catapult and launch the aircraft model into a lake, and more thorough tests use water tanks where the airplane model is pulled along the water surface while being suspended on a rig. This allows to measure forces, while the catapult launch will only show the dynamics of a water landing. Results like these could be used to calibrate the computer model, so you can be sure it behaves like the real thing.