Bou Regreg

The Bou Regreg is a river in western Morocco that flows into the Atlantic Ocean between the cities of Rabat and Salé. This river's estuary is known as Wadi Sala. The river is 240 kilometers long, with a tidal estuary that extends upriver for about 24 kilometers. Its average discharge is 23 m3/s, but it can reach 1500 m3/s during floods. The river rises in the Middle Atlas mountains at an elevation of 1627 meters on the level of Jbel Mtourzgane (Province of Khemisset) and Grou (Province of Khénifra) and flows to the Atlantic Ocean, separating the cities of Rabat to the south and Salé to the north.

The Bou Regreg's water quality issues include tidal saltwater intrusion, excessive nitrate runoff from agricultural land uses, and mercury contamination thought to be caused by the use of certain pesticides within the drainage basin.

The Phoenicians and Carthaginians, who established several colonies in Morocco, lived on the banks of the Bou Regreg, about two kilometers from the river's mouth at the ancient site of Chellah. This archaeological site contains the ruins of a Roman town known as Sala Colonia, which Ptolemy referred to as Sala. Chellah was an important ancient port city with ruins such as the Decumanus Maximus, or main roadway, as well as a forum, a monumental fountain, a triumphal arch, and other Roman ruins.

Length: 240 km (150 mi)