[5] Réghaïa lake is characterized by a Neogene syncline of fine Miocene and Plio-Quaternary deposits located midway between Gibraltar and the Sicilian Channel.

[7] In the northern part of the valley, more or less fixed dunes stretch out, separating the mouth of the Oued Réghaïa from the Mediterranean Sea.

According to Emberger's climagram, the Réghaïa marsh is located in the sub-humid bioclimatic zone, characterized in particular by dry, hot summers and mild, wet winters.

The lake's actual functions are coastal erosion prevention, flood control, sediment capture and water quality maintenance.

The Réghaïa maritime marsh plays an important role in containing and regulating wadi flooding, as well as preserving certain ornithological species that nest there.

The vegetation, which grows in narrow strips along this coastal cordon, stops and fixes the sand, forming a barrier that closes off the mouth of the Oued Réghaïa.

[12] The Réghaïa marine zone is located around the small Agueli or Bounettah island, which is a nesting ground for certain ornithological species.

In such a diverse environment, the fauna is obviously very varied, with herbivores and carnivores contributing to the food chain of the maritime marsh.