The depth of water is largely irelevant since evaporation can only take place at the surface. All other conditions remaining constant, water will evaporate faster the hotter it gets. Looking at the graph of vapour pressure versus temperture in this Wiki article I would estimate that water would evaporate about 8 times faster at 100 degrees (when it would be boiling if we are talking degrees C) than it would at 50 degrees.
Here's the vapour pressure graph. At 50 degrees the VP is about 100 torr and at 100 degrees is just short of 800 torr