Satellite data is used to determine water depth by accounting for the changing turbidity of the water over time and without requiring calibration using SONAR measurements. Radiance values at multiple wavelengths sensed at both a first time and a second time are stored in a database. Modeled reflectance values are calculated for a defined surface area on the water based on an assumed depth, assumed water constituents and assumed bottom cover. A plurality of differences between the modeled reflectance values and the reflectances sensed at the two times are calculated. A bathymetry application module minimizes the sum of the differences between the modeled and sensed subsurface reflectances by varying the assumed depth, bottom cover and water constituents. The differences are weighted based on wavelength before being summed. The depth that results in the minimized sum of the differences is the estimated depth, which is displayed on a graphical user interface.