Is wadi gaza a freshwater river? Also, is it a perennial river?

Is the river Thames freshwater?

• With the whale that was found in the river Thames, I was wondering if the river had saltwater. Does anyone know the source of the river?

• Answer:

  Yes, it's freshwater, at least in the sense that it is not salt or marine... I doubt if it's really "fresh" anymore. Whales entering rivers and estuaries are not rare occurrences. Here in Argentina we have records of whales in Río de la Plata (which is partly estuarial) and even in Paraná river. Usually the animals are not in good health or they're too young and disoriented, but ultimately no one knows what makes them go upstream into a river.