Large swaths of land have been recovered from the sea throughout history. Modern technology has allowed for bigger projects even into open sea. For example, Palm Jumeirah sticks 5 km into the sea, and Palm Deira (which is under construction) will stick out 14 km into the Persian Gulf.
I don't think these affect Dubai's territorial waters, but one can easily imagine similar projects in other countries which would have an effect on them. Singapore, for example, lies very close to both Indonesian and Malaysian territories and is doing a lot of land reclamation.
With technological advances and increasing populations, need for land may become larger, and bigger projects may be undertaken in the future. It is easy to see how such projects could cause international tensions.
So what happens to the territorial waters (or other relevant borders), when a country reclaims sea land that protrudes out of its coast line? Are there any rules in international law that deal with this kind of situation?