Twinkle feels like a cute word. Brings memories of Twinkle, Twinkle Little Star. In the case, twinkling sunlight on the water is always something I am drawn to. Usually, I refer to this as "sparkle" on the water from the sunlight. It's usually off in the distance. However, in this case, the water sparkle is up close and very clear which is brighter than a sparkle. It is a twinkle.