The Orange River mouth is located on the arid Atlantic coast at South Africa's border with Namibia. The nearest town is Alexander Bay. It is a delta-type river mouth, consisting of a series of braided troughs interspersed with sand banks, channel bars and islets, with a tidal basin and salt marshes. Extensive mudflats occur at the mouth, and large areas of intra-fluvial marsh occur upstream of the mudflats. This system is so dominated by freshwater that it has few estuarine characteristics. The major part of the vegetation of the lower part of the river is typical of a low-salinity wetland. Common plant species include the sedges Scirpus and Sporobolus, saltworts Sarcocornia and common reed Phragmites australis.