not nice clean deep black water, more harbour water colours, greens, browns, and what colour is slime?
Most developed nation harbours are clean due to modern legislative controls on pollution, etc.
Musafa (Abu Dhabi):-
The Tyne (after heavy rain and storms):-
Port of Los Angeles (an actual American port! Surprisingly clean, given their general attitude to passing laws that will cost campaign contributors money):-
You have to look carefully but you can glimpse the turgid mess that is the waters of Mumbai harbour:-
Remember: the black water is down to the depth and the weather - even deep water has a blue hue in the top layer if the sun is shining. In shallower water the sun reflects off of the sand on the bottom and you get a "double filter" so it looks bluer - and can appear cyan viewed from height (the water filters the other parts of the light spectrum in much the way the atmosphere does as they have a longer wavelength than the blues and violets and are not scattered towards the eye as much). Green water is combination of temperature (affecting density) and suspended sediment - so in shallow water prone to current turbulence (such as the southern North Sea) you get dark green water on non-sunny days with a brown tinge from the suspended silt and sand. On a sunny day you get a blueish-green colour with the grains of the suspended sediments clearly visible if you look over the side. It takes a shallow-submerged object to be passing to allow one to perceive that you can see a good two or three metres below the surface. Nightmare for visual surveys, though - it's like peering at a pipeline through dense fog.
Pick your harbour, pick your season to work out your colour, basically.
