Culvert Inlet Protection: Keeping Sediment Out of the Pipe
What culvert inlet protection is and how to choose the right approach
Culvert inlet protection keeps sediment from entering the upstream end (the inlet) of a culvert, the pipe that carries water under a road, driveway, or embankment. Because a culvert concentrates flow into a pipe, protecting its inlet prevents the pipe from clogging with sediment and keeps that sediment from being carried downstream and discharged.
What is culvert inlet protection?
A culvert is a pipe or structure that conveys water under an obstruction such as a roadway. Its inlet is where runoff enters the pipe. Culvert inlet protection places a sediment barrier or filter at that inlet so sediment settles out before water enters the culvert. This protects the pipe from silting up and protects downstream channels and waters from the sediment load.
Approaches to culvert inlet protection
- Sediment barriers placed around the culvert inlet to pond water and drop sediment.
- Fillable barrier devices that act like weighted wattles to slow and filter flow.
- Rock or aggregate protection combined with fabric to filter and dissipate energy.
The right approach depends on flow volume and velocity at the culvert. Higher-velocity or larger culverts call for more robust, energy-dissipating measures.
How it differs from storm drain inlet protection
Storm drain inlets are usually flat grates or curb openings in developed areas, while culvert inlets are pipe mouths in channels and embankments, often with higher and more concentrated flow. Devices made for flat grates may not suit a culvert inlet; instead, barrier and fillable devices that pond and filter flow ahead of the pipe are typically more appropriate.
Choosing culvert inlet protection
Consider the culvert size, the slope, and the expected flow. For lower-flow situations a fillable barrier or light-duty filter can work; for higher flows, pair sediment barriers with energy dissipation. The Inlet Protection Product Selector can help you weigh device options for your inlet.
Not sure which product fits your site? Use the Inlet Protection Product Selector, our free interactive tool under the Resources menu, to answer a few plain-language questions and get matched to the right inlet protection device, type, and size for your storm drain or curb inlet.
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Shop Inlet ProtectionUse the Inlet Protection SelectorFrequently Asked Questions
What is culvert inlet protection?
Culvert inlet protection is sediment control placed at the upstream mouth of a culvert pipe, so sediment settles out before water enters the pipe. It keeps the culvert from clogging and prevents the sediment from being carried downstream.
How is culvert inlet protection different from storm drain inlet protection?
Storm drain inlets are usually flat grates or curb openings in developed areas, while culvert inlets are pipe mouths in channels and embankments with higher, more concentrated flow. Culverts typically need barrier and fillable devices that pond and filter flow ahead of the pipe.
What devices are used for culvert inlet protection?
Approaches include sediment barriers placed around the inlet to pond water and drop sediment, fillable barrier devices that act like weighted wattles, and rock or aggregate protection combined with fabric to filter and dissipate energy.
How do I choose culvert inlet protection?
Consider the culvert size, slope, and expected flow. Lower-flow situations can use a fillable barrier or light-duty filter, while higher flows call for sediment barriers paired with energy dissipation.
Why protect a culvert inlet?
A culvert concentrates flow into a pipe, so an unprotected inlet lets sediment clog the pipe and pass downstream. Protecting the inlet keeps the culvert clear and reduces sediment discharge to downstream channels and waters.