Learn Dutch: Wij rekenen erop dat de droogte eindigt doordat het veel regent. - We are counting on the fact that the drought will end because it rains a lot.

Doordat is used for an objective cause—a direct, physical cause-and-effect that happens independently of human will. Omdat is used for personal reasons or human motivations. Since rain mechanically causes a drought to end, doordat is the correct choice.

What is erop doing in this sentence?

The verb phrase is rekenen op (to count on). When you want to say "count on it", Dutch replaces op het with the pronominal adverb erop. Here, it acts as a bridge to the next part of the sentence, literally meaning: "We count on it that..."

Why doesn't the verb eindigt go at the very end of the sentence?

This sentence contains two separate subordinate clauses: dat de droogte eindigt and doordat het veel regent. In a subordinate clause, the verb is sent to the end of its own specific clause. Therefore, eindigt sits right before the new doordat clause begins.

The English translation says "will end", so why does the Dutch sentence use the present tense?

Dutch frequently uses the simple present tense (like eindigt and regent) to talk about the future. As long as the context makes it clear that we are anticipating an upcoming event, you do not need to use a future auxiliary verb like zullen.