In the second calculator, assuming that your entry values were in feet, the number of surface acres is returned, along with the number of acre-feet and acre-inches of water volume, based on the entered depth. Both are units used to measure volumes of water, typically for use in irrigation. One acre-foot is the volume of water sufficient to cover an acre of land to a depth of 1 foot, is equal to 43,560 cubic feet, approximately 325,851 U.S. gallons (approximately 1233.48 cubic meters). At year 2000 considering American rates of consumption, on average 1 acre-foot of water is enough to meet the industrial and municipal demands of 4 people for a year. An acre-inch, the volume of water needed to cover an acre to a depth of 1 inch, 1/12th of an acre-foot, is approximately 27,154.25 gallons or approximately 102.79 cubic meters. These figures can all be used to determine fish densities for cold or warm water ponds or lakes. This link is excellent density information for your pond.