We don't have synonyms for springtides yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are spring tide, springtime and springtide.
(n) :
Alternative spelling of spring tide. [The tide which occurs when the moon is new or full; the effects of the Sun and moon being reinforced so that this tide is of maximum range.]
(n) :
Alternative spelling of spring tide. [The tide which occurs when the moon is new or full; the effects of the Sun and moon being reinforced so that this tide is of maximum range.]