Check Dam - Small Barrier for Erosion Control Guide

A check dam is a small barrier placed in a swale, ditch, or channel to slow stormwater flow and reduce erosion.

What It Is

Check dams are low obstructions made from stone, gravel bags, logs, or manufactured erosion-control materials. They are installed across a drainage path to slow water, spread flow, and encourage sediment to settle out instead of washing downstream.

They are not intended to stop water entirely. Their job is to reduce velocity so channels and slopes are less likely to erode during storms.

Types

Residential and sitework check dams may be built from rock, fiber rolls, wattles, sandbags, or other approved temporary erosion-control materials. Permanent landscape or drainage designs may use stone structures sized for the expected runoff.

Where It Is Used

Check dams are used in swales, drainage ditches, temporary construction site channels, and landscaped runoff paths where water is moving fast enough to cut soil. They are part of erosion control rather than finished plumbing drainage.

How to Identify One

A check dam appears as a low ridge crossing a shallow channel, often with the center set slightly lower than the edges so overflow stays controlled. If water is cutting around the sides or scouring underneath, the dam is not working correctly.

Replacement

Replacement or rebuilding is needed when the material washes out, settles too low, or no longer slows water effectively. Correct spacing and anchoring are just as important as the material itself.

Check Dam — FAQ

What does a check dam do?

A check dam slows water moving through a ditch or swale so the flow causes less erosion. It also helps sediment settle out instead of being carried farther downhill.

Are check dams permanent?

Some are temporary erosion-control measures and some are built as permanent landscape drainage features. The material and installation method determine which type they are.

Why is water cutting around my check dam?

That usually means the dam is too low at the sides, poorly keyed into the soil, or undersized for the runoff. Water always finds the path of least resistance if the shape is wrong.

Can homeowners use check dams in yard drainage?

Yes, when they are used appropriately in swales or erosion-prone runoff paths. The design still has to direct water safely and avoid sending concentrated flow onto neighboring property.