A single word or short term for "suffering or death caused by lack of water/thirst"? How about "dry up to death?"
Dry up: make or become completely dry.
For example,
Fidgety [ a frog] had not escaped. Fidgety had not become a cat snack. He'd just crawled up into the [ceramic] turtle to hide. And while we searched and despaired and let all the water in his aquarium pond habitat evaporate, he had slowly starved and dried up to death. source
Four slugs dried up to death on my driveway. We are having a funeral for them at 12 noon on Tuesday. It's a slug awareness day. Come dressed as a slug and bring your slime. source
dry: adj. 9) desiring drink; thirsty. 14) dehydrated. Random House Kerneman Webster's Dictionary, Ed. 2010.