Unexpected rain events or snowmelt in the springtime can cause water to flow over the top of culvert pipes and leave a muddy mess in front of your driveway.
There are a variety of ways to prevent this from happening and increase the life of your culvert.
Surrounding the culvert pipe with rock as it comes up out of the ground on both ends can help prevent some erosion, buildup of dirt, and further damage to the structure. To avoid having the rocks wash away with water, apply a geotextile fabric over them and anchor it well. This will also help prevent grass and other plants from growing through the rocks and will help keep water from seeping into the pipe.
Whether you want to drain rainwater more easily away from your home or create useful stream crossings, a culvert is one of the best alternatives.
However, it can be expensive to install or replace when damaged by water.
I’m sure you’ve seen a water-covered culvert pipe and the mess it creates.
If you want to save some money and give the culvert a little extra protection, try putting rocks around it.
This blog article will go through how to lay rocks around the culvert and what you can do to help prolong the life of your pipe.
Table of Contents
Expected service life of culverts
Sections of a driveway that frequently flood, or where the water level is higher than the surrounding area, will require a culvert.
Drainage culverts are an excellent solution to help prevent erosion, flooding, or pooling of water on your property.
How long a culvert lasts is dependent on many factors, including the make-up of your soil, traffic patterns, and general weather.
Culvert lifespan will vary based on size, environment, and traffic.
If you are wondering how long a culvert lasts – consider this:
Metal culverts typically last between twenty and fifty years but can come with a lifetime warranty depending on the manufacturer.
The ones made with reinforced concrete last even longer.
In many cases, a concrete culvert can last 100 years or as long as your home.
Many people usually have their culverts replaced only because they want to change the appearance.
Ditch and drainage specialists recommend having your culvert inspected and repaired when needed to ensure optimal performance and long-term use.
Find Out: Home Inspector as a Side Job: Pay, Pros, Cons, Qualification
Utility companies may also replace a culvert as part of their annual maintenance, which often includes cleaning and clearing the culvert.
It’s important to note that the expected lifespan will vary based on how well it is maintained.
If culverts are not cleaned regularly they can become clogged, which can cause a back up of water that could have been drained if the culvert were clear.
How to put rocks around culvert
Small streams are often on the land.
Even if they are dry most of the year, they have steep banks that prevent cars from crossing them.
To facilitate the crossing, a small culvert is placed under the road.
This allows water to pass through and cars to cross.
Sometimes, the water’s force can be so great that it washes out soil from around the culvert.
If it is not repaired, it can be dangerous for cars and people.
It is important to surround the culvert with rocks to protect it from erosion, and thus avoid possible accidents.
The first step is to ensure you have all the necessary materials, machinery, and manpower.
The materials required include asphalt, gravel, sand, soil, and rocks.
Machinery required is a backhoe – also called a digger or excavator – for digging and moving gravel, sand, and rocks; a roller for compacting the base; and various heavy equipment.
Manpower required is that of the people who are actually digging, filling, transporting, and preparing the gravel.
Step 1: Prepare the base
The first step is to create a layer of large rocks on the entire surface next to the culvert.
The aim is to cover an area that can support heavy machinery.
This requires a backhoe and a roller, so be sure to have enough people for digging and rolling.
The gravel must be compacted before the next step.
The level of compactness depends on the material’s density and cohesiveness.
If it is composed of pebbles or small rocks, they have to be placed close together so that the roller can compact them.
If it is a coarse material such as sand, gravel, or crushed rock, it will be enough to distribute the material on the land and roll over it repeatedly.
Step 2: Add geotextile material to both ends of the culvert
Once the base is prepared, the next step is to cover the gravel layer with a protective layer of geotextile fabric.
The geotextile is a material that provides a barrier between the gravel and the ground.
It also helps to enclose anything beneath it. This can be soil or rocks that were taken from around the culvert and piled up in order to prepare the gravel base.
To secure the geotextile material or landscape fabric, rip rap can be placed around it with large rocks.
This material provides solid support for the materials placed underneath it and holds them in place.
Step 3: Fill the area
Once that is done, you can fill the area around the culvert with a layer of gravel.
This layer will need to be about three inches thick and compacted with a roller.
If it is not thick enough, the material might not be secure enough to support large vehicles.
If it is too thick, the culvert will “sink” as the weight of the gravel distributes itself over a larger area.
Use asphalt for paving the area where vehicles will be crossing.
Protect culvert from being washed away
Culverts can be much more difficult to permit than bridges.
Gravity does all the work in a bridge, while culverts need to have water flow through them.
Therefore, the concentration of water is much higher in the narrower culvert pipe.
Culverts are particularly vulnerable to flow velocity, which can cause the erosion of either the soil or rocks around it and can undermine their ability to function properly.
When a culvert starts to fail, this can increase the depth of the water in the crossing, which increases the force against downstream culverts, possibly causing an entire road to wash out.
There are several methods of protecting culverts, depending on the material in which they are placed.
- Protect culverts with riprap.
- Fill voids using resin for small culvert projects.
- Use expanded polystyrene (EPS) geofoam for extensive roadway systems
