You should never swim alone. Never enter a fenced-in pond unless you have permission from an adult. Fences are there for your protection and should be respected. Another area on farms you can drown is in liquid manure . Manure, unlike water, is heavy and will drag your body to the bottom.
Farmers usually store liquid manure in pits, slurry storage tanks or lagoons.
A pit storage unit is located under the barn and can only be entered through a manhole. You should not play in or around these manholes. If you were to fall in, nobody would hear you except the animals. Slurry storage tanks are above ground structures. They look like short, fat silos.