Crossword Clue:

STRATH a wide river valley

AnswerCrossword Clue
STRATHWide river valley: Scot.
ESTUARYWide mouth of a river.
ESTUARYWide part of a river where it meets the sea
PLATTERiver facetiously described as "a mile wide at the mouth, but only six inches deep"
LOIRERiver with a chateau-filled valley
LOIREFrench river with a famously picturesque valley