The Thirst Mod for Minecraft, developed by "tarun1998" and "Medievor", challenges those playing in survival mode just a tad bit more by introducing a "thirst" bar. This mod adds a thirst bar - that, yes, measures the players thirst - above the health bar. This thirst gauge depletes at a quicker rate than the hunger bar and when the player starts to near "parched", their health begins to decline.
The bar refills according to how many drinks the player takes. Depending on the biome the player is in, gulping down water from just any source can poison the player.
This mod is great for the players who have mastered survival mode and would like to add another challenge for themselves.