When I saw this on special exhibition at the Denver Art Museum in July of 2003, it took up pretty much a good two-thirds of a wall. It was substantial compared to the other Sargent paintings in the room (Sargent and Italy).
I have two images of this painting at this site (this one and the step closer one) and neither image does the panting any justice! Towards the late afternoon I found I had the room almost to myself and from the middle of that room, say something like 15 feet away (2+ meters), the water just comes alive and shimmers with the most beautiful submerged rocks under the perfectly crystal-clear water in front of this stone-dock area. In total, there is so much going on I could of spent hours with it. Even in the background there are endless things to ponder which aren't represented well at all in these images. But always -- always it was that shimmering water I continually came back to in the foreground that just had me transfixed.
Close-up, in the space of what most people have to view the painting in a crowded room (say something like three to four feet away) the hatched gold and yellow painted strokes representing the refracted water's surface seems overdone, haphazard, and the submerged rocks seemed two dimensional and flat; but if you are able and lucky enough to back away, with an unobstructed view, and give yourself more than sixty seconds of a constant gaze, the depth of the water becomes apparent, the submerged rocks become 3-dimensional and the water comes to life!
As much as I try, the power of Sargent is just not representable on the net!
Sargent in Italy, 2002-2003