Regardless of the type or size of farm pond you design, you’ll need fresh water flowing into it to replace what’s lost through evaporation and overflow. Surface runoff from a small watershed area is a common source, but many parts of the country either experience too little or uneven rainfall that is hard to rely on for a year-round pond.
Seasonal and constant springs and wetlands are great sources of water for ponds, especially for small ponds that don’t face regular periods of high demand. Even seasonal springs and vernal ponds can help refill manmade ponds when they’re designed not to lose water between the seasons. Streams and creeks that run through your property are easily diverted to keep a pond filled without losing much of its downstream flow. As long as you divert enough overflow back into the stream without causing water quality issues, your downstream neighbors won’t notice you’ve made use of the waterway. If you own full rights to a stream or creek, then you can definitely dam it to create a deep pond with a steady level.
Some ponds are designed to fill manually. These ponds are usually connected to a well. Filling a pond with a hose or from your home’s well may work for a very small feature of only a few hundred gallons, but any pond of 1/10th of an acre or more in size will need another source of water. Well-fed ponds are usually designed as natural holding tanks for solar and wind-powered pumps so water is freely pumped anytime the energy source is available.
