Answer:

reservoir

Answer	Crossword Clue
RESERVOIR	Source of a vital supply
RESERVOIR	Croton, for instance.
RESERVOIR	Ashokan or Croton.

RESERVOIR	Lake Mead is the world's largest.
RESERVOIR	Water supply.
RESERVOIR	Artificial lake.
RESERVOIR	Large supply.
RESERVOIR	T.V.A. facility
RESERVOIR	Dam result, often
RESERVOIR	Water storage site
RESERVOIR	Water tower