Possible Clues:

• River rising in central Angola flowing south-eastwards to Namibia
• River forming part of the border between Angola and Namibia
• Water flowing into Botswana’s ____ Delta does not reach the sea, but evaporates
• African river with a delta about 400 miles from the sea
• River in south-west central Africa rising in Angola
• Authority for a vehicle to proceed by river to Southwest African border
• Botswana river