Dutch YA fantasy book about witches who can't cross streaming water

[Guus Bosman]

I am looking for a Dutch children's book series, but I don't know the titles or author. I read it when I was around 10 to 12 years old, between 1988 and 1990. It was an exciting series, with more than one book, at least 4 as far as I can remember. It was about children who come into contact with witches. The story took place mostly at night. An important plot element was that witches could not fly over running water, which allowed the main characters to occasionally find safety.

[Capn]

Anything here?
Children's/YA in Dutch:
https://www.goodreads.com/list/show/8...

Do you think it was originally written by a Dutch author, or might it have been a translation?

Can you remember anything about the setting? Or any more details of some of the plot points? :)

Was it illustrated?