Some snakes in Africa also prefer dry river beds. I would not be surprised if that is the case for scorpions too.

It’s an easy source for getting water too. Not only that, coming worldwide via global warming:

Intense storms in Egypt unleashed a massive swarm of scorpions from their nests, stinging 450 people and killing 3: https://www.yahoo.com/news/intense-storms-egypt-unleashed-ma...