I think it is melting snow or tropical rains or underground lakes
The Niger flows from north to south .
the source of the great river ouse is south-east of Farthinghoe,Brackley Northamptonshire
amazon river
The south and east of Africa has the highest elevations.
south east
It flows north because that it the way the surrounding land forces it to flow. Water always flows from higher elevations to lower elevations. It just happens that in the case of northeastern Africa, the higher elevations are further south than the lower elevations. As a result, the water flows from south to north.
There are 3 River Dons in England. River Don, Lancashire, England River Don, South Yorkshire, England River Don, Tyne and Wear, England
The River Ver is a river in Hertfordshire, England. The river begins in the grounds of Markyate Cell, and flows south for 12 miles.
The Andes mountain streams
The source of the Amazon is in Brazil.
Pikes adventure was of the south west of the Louisiana territory. The goal of Pikes expedition was to find the source of the Red River
slave bringing their culture with them