Building a farm pond starts with the site and the watershed, then a soil check, a core trench and a dam of clay packed in thin layers, a pipe and an auxiliary spillway, and seed on every bare slope. Skip a step and the pond leaks, silts in, or loses its dam in a big storm.
Step one: decide what the pond is for
A pond for fishing, one for cattle, one for wildlife and one for the view from the porch are four different ponds. The use sets the size, the depth, the shape of the banks and how much shallow edge you want.
Fish need enough deep water to make it through a hot summer and an iced-over winter. Livestock need water late in a dry August. A pond near the house is mostly about looks and access. Decide on the main use first, then design for it. Our guide on how deep a pond should be in Illinois covers depth for each use.
Writing it down helps. It keeps the plan from drifting once the digging starts.
Step two: pick the site and check the water source
There are two basic kinds of farm pond. A dugout is dug down into fairly flat ground and fills from runoff or groundwater. An embankment pond holds water behind a dam built across a draw.
Either way, the water has to come from somewhere. The area draining into the pond should be big enough to fill it, but not so big that every storm floods the spillway and brings in silt. Look for buried lines, tile lines, and creeks or wet ground that may bring in other agencies.
Your county soil and water conservation district and NRCS office can help with planning. Before you commit, read our Illinois pond permit guide to find out who needs a call.
Step three: find out what the soil will hold
A pond is only as good as the ground under it. Clay holds water. Sand and gravel let it through. Clay content can change from one spot to the next, even in the same field.
So dig test holes before you dig a pond. An excavator can open a few holes in the basin and the dam line in a short time. Look for sand or gravel seams, and note how deep the good clay goes.
If a seam turns up, it does not always kill the site. It can sometimes be dug out and replaced with packed clay, or the pond can be shifted. Finding it now costs far less than finding it after the pond leaks.
Step four: clear and strip the site
Trees, brush, stumps and roots come out of the basin and the full footprint of the dam. Then the topsoil and sod are stripped off the dam area and stockpiled.
This matters more than it sounds. Roots and organic soil left under a dam rot over time. They leave voids that water can follow straight through the embankment. That kind of leak can grow fast.
Keep the stripped topsoil. It goes back on the finished dam and banks to give grass a good start. If the site is grown up in brush or timber, clearing is its own step and should be planned before the dig.
Step five: core trench and a compacted clay dam
Along the center line of the dam, a core trench is dug down through the topsoil and any sandy layers into tight clay. It is backfilled with good clay, packed as it goes. The trench ties the dam to the ground below and blocks water from sneaking underneath.
The dam itself is built up in thin layers of clay, each one compacted before the next goes on. The clay needs to be moist enough to pack well, not dry and crumbly or wet and sloppy.
Seepage through a dam is a known cause of failure. Fast seepage carries soil with it and can open a pipe through the embankment. A tight core and good compaction are what prevent it.
Step six: pipe, spillway and seed
Most embankment ponds have a pipe through the dam that sets the normal water level and carries ordinary overflow. That is the principal spillway.
Every dam also needs an auxiliary spillway. It is a wide, grassed channel cut into undisturbed ground at one end of the dam. When a big storm comes, it carries water around the dam instead of over it. Water pouring over the top of an earth dam erodes it and can take the dam out.
Once the earthwork is done, the topsoil goes back on the dam and banks, followed by seed and mulch. Keep trees and brush off the dam for good, because roots open paths for water.
Step seven: let it fill, then plan the rest
How fast a new pond fills depends on the weather and the size of the watershed. It can take one wet spring or a lot longer. A wet stretch speeds it up and a dry one slows it down. Plan stocking once the water is up and the banks have grass on them.
If you want a sense of what moves the price before you call, read what it costs to build a pond in Illinois.
Then call James at (815) 240-9065 or send a pin drop and photos through the contact form. He will walk the draw, look at the soil and talk through the dam and spillway. See our pond digging and renovation page for everything we build.
The Short Version
- Decide what the pond is for first; it sets the size, depth and banks.
- The watershed has to fill the pond without flooding it with every storm.
- Dig test holes before the pond; clay holds water, sand and gravel seams leak.
- A core trench and a dam of clay packed in thin layers stop seepage.
- Every dam needs an auxiliary spillway, and every bare slope needs seed.
Quick Answers
What is a pond builder called?
Usually an excavating contractor or pond contractor. Look for one who talks about soil, the dam, the core trench and the spillway, not just digging. That is the part that decides whether the pond works.
Can a pond be made without building a dam?
Yes. A dugout pond is dug into fairly flat ground and fills from runoff or groundwater. It still needs soil that holds water and a safe path for overflow.
Do I need clay to build a farm pond?
You need soil that holds water, and in most cases that means clay. Test holes show what is there. If the clay is thin or has sand seams, it can sometimes be fixed with packed clay brought from elsewhere on the site.
How long does it take to build a farm pond?
Planning, soil checks and any permits often take longer than the digging. The dig itself depends on the size, the soil and the weather. Filling depends on rain. Call (815) 240-9065 to talk through the timeline for your site.
See our pond building service or call (815) 240-9065.