Waterfall stacking: Can you leave your tripod and ND filter at home?

If the intention is to bring the viewers attention to the water, you could consider biasing your exposure for that element of the image, perhaps have a go at exposing for the sunlit portion (top half of the image) and then exposing for the water and mixing the 2 in photoshop, of course a tripod would be the answer to both the longer exposure required, and taking the 2 images without camera movement.