What is the punishment reinforcer for not drinking water? How do I use Chart/graph to compare baseline and program data?

We can explain the concept of what punishment is and how it could be tied to not drinking water, as well as explain how you could chart or graph results with a study group that was not drinking water and a control group that was consuming the recommended amount of water.   Unfortunately, you omitted some of the information we would need to write an answer specifically addressing the experiment you appear to be referencing.  

While many people think of punishment as intentionally inflicting something bad when a person or animal engages in undesired behaviors, not all punishment involves a third-party’s intervention.  Instead, punishment actually refers to a change in circumstances after a behavior is exhibited, which should lead to a change in the behavior.  Punishments can be positive or negative.  Positive punishment is not the same as rewards, though the word positive can be misleading.  Instead, it means adding something to the situation.  Because punishments are meant to dissuade behavior, positive punishment would mean adding something aversive to the scenario.  Corporal punishment is an example of positive punishment.  Negative punishments involve taking something desirable away from the scenario.  Grounding a teen from electronics is an example of a negative punishment.

Not drinking enough water is related to a number of side effects.  The most notable and immediate side effect is probably thirst.  Other side effects include headaches, fatigue, constipation, dull skin, weight gain, and dry mouth.