How to Build a Water Gap That Won’t Let You Down When It Floods
April 29, 2025
If you’ve been ranching in Texas long enough, you know this truth: sooner or later, it’s gonna flood. Could be next month, could be next year—but when that water comes rushing through, you want to make sure your fences can take the hit.
One of the trickiest parts of any fence line is what we call the water gap—that section where your fence crosses a creek, drainage ditch, or low spot. Done right, it holds your livestock in and lets water out. Done wrong, and you’ve got a mess on your hands (and probably some cattle roaming where they shouldn’t be).
So, let’s talk about how to build a water gap that works with the water—not against it.
First off, what exactly is a water gap?
Great question. A water gap is the part of your fence that crosses any spot where water runs through—whether it’s a trickling creek most of the year or a flash flood zone when the rains hit hard.
You need something flexible here. A solid fence will either wash away or act like a dam, building up pressure until it gives out. The goal is to let water (and debris) pass through without tearing your fence apart.
Why do water gaps fail?
A few reasons:
- Too rigid: If your water gap doesn’t have any give, rising water will rip it out.
- Weak anchoring: Posts too close to the flow or not set deep enough? They’ll wash out faster than you can say, “Where’d my fence go?”
- Debris buildup: Ever seen a log jam? Enough branches and junk get caught, and your fence becomes a wall the water will knock down.
But here’s the good news: with a little planning, you can build a water gap that holds up.
5 Tips for Building a Water Gap That Stays Put
1. Let it swing!
One of the smartest things you can do is install swinging panels that can float or move when water rises. Think of them like gates without hinges—they lift when they need to and settle back down when the water goes down.
- Quick Tip: Use a lightweight cattle panel or wire mesh. Attach the top firmly but leave the bottom free to move, maybe with a chain that keeps it from swinging too far.
2. Anchor those posts like you mean it
Your posts on either side of the water gap need to be rock solid. Set them deep (deeper than your regular line posts) and pour in some concrete. This isn’t the place to skimp—those posts take the brunt of the force when the water pushes through.
- Even better: Angle brace them or add deadman anchors for extra hold.
3. Breakaway connections are your friend
Here’s a little trick: use breakaway clips or wires in the water gap section. If the pressure gets too high, the fence can give way just enough to save the rest of the line. You can reattach these afterward without rebuilding the whole fence.
4. Give debris room to move
This is a big one: design wide enough gaps for logs, branches, and other junk to pass through without clogging up. A clogged water gap turns into a dam real fast.
If you’ve got a spot that regularly sees debris flow, you might need to leave that section open or just hang loose chains or cables across to discourage livestock but let everything else through.
5. Use materials that can take a beating
Texas weather is tough. Make sure your water gap uses galvanized wire, high-tensile panels, or pipe fencing—stuff that won’t rust or rot after sitting in water. Stay away from untreated wood here; it won’t last.
Every ranch is different—your water gap should be too
No two ranches (or creeks) are exactly alike. How much rain you get, how fast the water moves, what kind of livestock you’re running—all of that affects how you should build your water gap.
That’s where we come in. Fred Nuncio Fencing has been helping Texas ranchers like you build fences that last since 1995. We know the land, we know the weather, and we know how to build a water gap that won’t leave you fixing fence after every storm.
Need Help Designing or Fixing a Water Gap on Your Ranch?
Reach out to us for a free consultation. We’ve been keeping Texas fences standing strong since 1995.
Because your ranch is more than just land—it’s your legacy.
FAQ: Water Gaps & Flood Fencing on Texas Ranches
The width depends on your typical water flow and debris load. A good rule of thumb is to make it wider than the average flood path, often 8-15 feet, but it varies by property.
Most livestock avoid moving water, but if the gap dries up seasonally, they might wander through. Adding chains, cables, or panels discourages crossing.
Galvanized pipe, high-tensile wire, or cattle panels are best. These materials resist corrosion and hold up better under flood conditions.
Electric fencing can work, but it should be installed above the flood line to avoid shorts or damage. Avoid running hot wires through low gaps.
After any heavy rain or flood event, inspect your water gap. Routine checks once a season help catch issues early, before they become expensive repairs.