Can waterfall foam be applied in damp conditions???

Ok so I just got my pond up but the waterfall is leaking!! So I drained
the pond down and tried to get most of the water out, but with rain
almost daily I don't think it will ever be totally dry. So will it
still attach to the liner if wet? Also do you know if it's very
flexible? Will it stick to the liner very well? My dog is already
running around the pond trying to dig it up! I looked online but
couldn't find this info. I did see someone post that "great stuff" is
the same??? Thanks for any help. Ouida