Rami designed a small pond for a restaurant. The diagram below shows the measurements of the pond. A composite figure created from two horizontal rectangular prisms, one on top of the other. The wider one is on top. The total height is 4 feet. The length of the bottom one is 12 feet. The width of the top one is 6 feet, the height is 2 feet, and the length is 18 feet.
How many cubic feet of water are needed to fill the pond?