Answer: headwaters

AnswerCrossword Clue
HEADWATERSRiver's source
HEADWATERSRiver's upper tributaries
HEADWATERSLake Victoria, e.g.
headwatersHEADWATER, the highest part of a stream or river before receiving tributaries
headwatersA tributary stream of a river close to or forming part of its source