The feel of the waterfall can be obtained simply by using a long exposure. I carry a 10 stop 77mm Neutral Density filter with me, with adapter rings that allow me to put it on all my lenses. Stick it on a tripod, get your exposure without the filter, put the filter on and add 10 stops of shutter speed and bam, you've got it. The HDR feel can be somewhat obtained through filters or tone-mapping, if you don't want to get into the HDR thing, but it's a neat thing to experiment with. I've found that since I moved to the D600 and D800 the dynamic range I get with those sensors allows me to get very natural looking HDR-like images from a single frame, but it's often easier with a 3-shot bracket provided everything that needs to remain still does so.