No rivers and no water is reality here for quite a while already. The islands rely a lot on desalination, and there is a big EU-funded project going on to create a desalination plant that not only is used to supply tap water, but the water basin of a new hydroelectric plant [0]. Desalination pretty much solves water issues, IF you have the energy (ideally renewable).
reply[0]: https://renewablesnow.com/news/construction-starts-on-200-mw...
Desalination solves water issues for tap water. Islands may be short on surface area.
replyI would also never use the word "solve", as this is just for human usage. The ecosystems themselves are irreversibly destroyed.