DeMundo 149:9 :ܡܬܕܟܝܐ ܡܐ ܕܛܝ݁ܦܐ ܒܫܦ̈ܥܐ‏ : (the earth) is purified when it is inundated with torrents
See the entire entry for ṭwp vb. to overflow, float