...
There is also JavaScript and Python API: https://code.google.com/p/earthengine-api/ (available only for a limited group of testers).
Water data in EE:
- HydroSHEDS, Drainage Directions, 15-arc second
- HydroSHEDS, flow accumulation, 15-arc second
- HydroSHEDS, hydrologically conditioned DEM, 15-arc second
- ... ?