In the event of a continent (or multiple continents) flooding - a result of rendering errors caused by faulty coastline ways and nodes, click here to visit the coastline info page, which highlights coastline nodes that can potentially cause rendering problems, and click here to see Thilo’s diary entry about fixing coastlines. These two links will help in fixing “floods”.
I would also like to add that Luciano made a page on the OGF wiki about making sure that the coastline ways that border your country don’t cause rendering problems (floods).
If you’re not clear on what you need to do to fix coastlines or maintain your coastline’s “integrity”, please visit the links above.
Thanks in advance.
Tom
EDIT 6:12p PDT: Also remember that coastlines update on the map every ~4 hours, so your edits to the coastline may not appear right away.

