winterbourne
A stream that only flows in winter or after wet weather, particularly in an area rich in limestone.
[F]rom the graveyard itself burst up one of those noble springs known as winter-bournes in the chalk ranges, which, awakened in autumn from the abysses to which it had shrunk during the summer's drought, was hurrying down upon its six months' course, a broad sheet of oily silver, over a temporary channel of smooth green sward.
Where it comes from
From winter + bourne (“seasonal brook or stream”), partly also from the placenames Winterborne, Winterbourne, which are derived from Old English winterburna (“stream that is full in winter”), from winter (from Proto-Germanic *wintruz, further etymology uncertain) + burna (“stream”) (ultimately from Proto-Indo-European *bʰrewh₁- (“to boil; to brew”)). The Old English word appears to have survived only in placenames.
Adapted from the Wiktionary entry winterbourne (CC BY-SA 4.0).