"When they are thirsty, I will give them water."
Translation:Až budou mít žízeň, dám jim vodu.
The sentence is about future. I will give them water when they are thirsty at some point in the future. Hence the will and hence the Czech future tense. There is no backshift to the present tense in Czech conditionals.
Different is this present sentence: Když mají žízeň, dávám jim vodu. When they are thirsty I give them water.
I would translate it as: Kdykoliv budou mít žízeň, dám jim vodu.
Note that it is indicative mood expressing some plans http://cokdybysme.net/pdfs/conditionalcz1108.pdf (point 9) It talks about what will happen at some time in the future.
Check the difference between point 8 and point 9 in the link:
Conditional mood (contrary-to-fact, irreal)
8) Kdybych měl čas a peníze, jel bych do Evropy na dovolenou. If I had the time and money, I would go to Europe on vacation.
Indicative mood (potential or expected plan)
9) Jestli budu mít čas a peníze, pojedu do Evropy na dovolenou. If I have time and money, I will go to Europe on vacation.
The grammar of conditional sentences is different in Czech and in English. English uses these zero, first, second and third conditionals with the associated rules for tense backshifts. Czech is different.
And there is some terminological difference too. The zero and the first conditionals become normal indicative mood sentences in Czech, not conditional mood sentences.
I really have no idea what you mean by tense backshifts. What I would really like ti know is what would be understood if I said "když mají žízeň dám jim vodu" because to me the first part of this sentence reads "when they are thirsty" and the second part " I will give them water" I really do not understand what is wrong :)
In English It is the first conditional. https://www.perfect-english-grammar.com/first-conditional.html
The first conditional is: if + present simple, ... will + infinitive
But it all happens in the future!!!
In Czech it is no special conditional, it is a normal sentence. They will be thirsty in the future, so they will get water (also in the future). Point 9 of http://cokdybysme.net/pdfs/conditionalcz1108.pdf
Our 2 sentences (in the 2 languages), each has two clauses. In English, the first is in the present tense, and the second in the future. In the Czech sentence the tenses are reversed, although the sustance is the same in the corresponding clauses, and the meaning of the Czech sentence is, presumably, preserved in the English version. It is somewhere between amusing and confusing for me to realize that a translation from Czech to English could scramble the tenses in such a fasion.
Nope, the tenses aren't reversed. Both clauses are in the future tense in Czech - which is logical, because both things (being thirsty and giving water) will occur in the future. English omits the future tense from the when/if clause for some reason.
Remember that the perfective aspect doesn't exist in the present, so "dám" (perfective) is automatically future tense. The present would be "dávám" (imperfective).
That's all right, don't worry about it. It happens to everyone on the path of learning.
But please try to place your reaction under the comment you're replying to (by hitting REPLY), instead of writing a brand new comment. It helps everyone who reads the discussion afterwards to make sense of it ;) Thanks.