Learn Hardcore Dutch: Wanneer de regen hevig valt, stromen kleine rivieren door de straten. - When the rain falls heavily, small rivers flow through the streets.

In Dutch, subordinate clauses (introduced by conjunctions like wanneer, als, omdat, terwijl, etc.) use “verb final” word order: the finite verb moves to the end of that clause. That’s why you get wanneer de regen hevig valt rather than wanneer valt de regen….

Why does the main clause start with stromen rather than the subject kleine rivieren?

Because the sentence begins with a fronted subordinate clause, the main clause must use inversion. After a leading element (here wanneer … valt plus a comma), the finite verb takes the first position in the main clause, pushing the subject (kleine rivieren) to second place: stromen kleine rivieren….

What’s the difference between wanneer and als, both meaning “when”?

wanneer is used for both “when” in time clauses (past, present, future) and in indirect questions.
als can mean “if” (conditional) or “when” for repeated events in the present/future.
In your sentence, wanneer focuses on the point in time at which the heavy rain starts. You could use als if you mean “whenever the rain falls heavily.”

Why is the adjective hevig not inflected (no –e ending) before the verb valt?

In Dutch, adjectives used as adverbs (i.e. to modify verbs) remain in their base form. They do not take the –e ending. So even though hevig looks like an adjective, here it works as an adverb (“heavily”), hence regen hevig valt.

Why is there a comma after valt?

When a subordinate clause precedes the main clause in written Dutch, you separate them with a comma. It clarifies the break between the “time clause” (wanneer … valt) and the main action (stromen …).

Why “door de straten” instead of “in de straten”?

door expresses movement through something (“flow through the streets”).
in would express location inside (“flow inside the streets”), which doesn’t match the image of water running along.

How is the plural rivieren formed from rivier?

Most Dutch nouns ending in –er form their plural by adding –en: rivier → rivieren. The pronunciation of the root stays the same, and the spelling changes to accommodate Dutch plural rules.

Why do we use de rivieren and not het rivieren?

All Dutch plural nouns take the definite article de, regardless of their gender in singular. So once you pluralize rivier, you always pair it with de: de rivieren.