Beach replenishment operations on Longboat Key, Fl. The photo was taken under heavy fog conditions. The ocean (Gulf of Mexico) is on the other side of the sand mound at the left. The water in the channels between the hills of sand on either side is outflow from a pipe carrying sand and seawater into the excavation. To give you an idea of scale, the sand mounds are 6-8' high, and the water depth varies from 3-4' in the channel. Once the required amount of sand is pumped into the excavation (about 6-8" over the full length), everything is covered up by the CAT bulldozers in the background. There are more photos in my portfolio of the CAT equipment at work.