freshetn.

freshet (n.)1590s, "stream of fresh water; stream flowing into the sea," from obsolete fresh (n.) "a stream in flood" (1530s), also "mingling of fresh and salt water," from fresh (adj.1). Old English had fersceta in the same sense. Meaning "small flood or increased flow of an ebb tide caused by rain or melting snow" is from 1650s.