I was contacted recently by NOAA regarding their release of bathymetry data for estuaries around the US. These colorful datasets “…are an interpolated data set representing the most up-to-date depth sounding information that was available at the time of publication (1998).” Read more about the data. You can view the page providing access to the GE files here, where you select a region and then select which estuary you want to view. Then look for a link to “Google Earth Visualization files”. Here’s a sample of the Pamlico Sound 
in North Carolina. Thanks NOAA!
Related: new shaded relief map of the terrain of the US from NASA SRTM data.
About Frank Taylor
Frank Taylor started the Google Earth Blog in July, 2005 shortly after Google Earth was first released. He has worked with 3D computer graphics and VR for many years and was very impressed with this exciting product. Frank completed a 5.5 year circumnavigation of the earth by sailboat in June 2015 which you can read about at Tahina Expedition, and is a licensed pilot, backpacker, diver, and photographer.