Flow Simulation - Time dependant inlet

Can you put a non permanent inlet in flow simulation? In an external simulation, I want a certain amount of water to run on a flat plane, but only a certain quantity, so I thought inlet inputs water (in air surroundings) for a certain time, if any function exists for that; I don't want a continuous flow. Or do I have to make a part or body representing water than do a mo​​​​​​​tion study?

Here is a capture : inlet from small surface on the right, trying to see if it'll go pass the black part left

Edu. ​​​​​​​