My feeling is that this is a photo from the Spectre set prior to construction. That is, that the tank is drained because something large is about to be built in front of the blue screen.
On CR, the Paddock Tank was used for the collapsing palazzo and the surrounding canal. With a very large model built in front of the blue screen.
My guess is that they are about to do something along those lines. Large models that need to be near water and with a big blue screen to place them into one of the locations via VFX.