Learn Arabic (Modern Standard): حيثما تجد القافلة ماء تخيم. - Wherever the caravan finds water, it camps.

حيثما (wherever) acts as a spatial conditional particle that governs two verbs, putting both into the jussive case (المجزوم). Here, the condition verb is تجد (finds) and the result verb is تخيم (camps).

If تجد is in the jussive case, shouldn't it end with a sukun (a vowelless consonant)? Why is it pronounced with a kasra here?

Yes, its true jussive form is تجدْ with a sukun. However, because the following word القافلة starts with a definite article (creating a consonant cluster), we change the sukun to a kasra to connect the words smoothly: تجدِ القافلة.

What is the root of تجد, and why does it look so short?

The root is و ج د (to find). It is an assimilated (Mithal) verb, meaning its first root letter is a weak letter (و). In the present and jussive tenses, this initial و is dropped, making it تجد instead of توجد.

The word ماء (water) is the object of the verb and therefore in the accusative case (منصوب). Why doesn't it have an extra alif at the end for the tanwin fatha?

Usually, accusative words take an extra alif (like كتاباً). But in Arabic spelling rules, if a word ends in a hamza (ء) that is directly preceded by an alif (ا), you do not add another alif after it. So it is correctly written as ماءً.