Flooding has come mainly from surface water run-off brought about by an accumulation of intense rain on 25th, 26th and 27th December on top of already saturated ground.
Daeth y rhan fwyaf o’r llifogydd o’r dŵr wyneb sydd wedi crynhoi yn sgil y glaw trwm a gafwyd ar 25, 26 a 27 Rhagfyr, hynny ar ben tir oedd eisoes yn wlyb iawn.