A few kilometres north of Errachidia on the N13, the Hassan Addakhil dam backs up the Ziz River into a long blue reservoir flanked by bare red mountains. The contrast between the water and the arid landscape around it is striking. A viewpoint on the road above the dam wall gives the best perspective.
The reservoir supports some fishing, and local families picnic on its banks at weekends. It is not a formal tourist sight but a pleasant stop if you are arriving from the Ziz Gorges and want to stretch your legs before entering town.