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Equipment Hub: Rural infrastructure: The old culvert

Andy Overbay for Progressive Dairyman Published on 24 August 2018

There has been much press lately about how our nation’s roads and bridges are badly in need of repairs or replacement. Recent bridge collapses are prime examples of how bad things can get when maintenance and replacements are forgone in the face of financial strains.

Secondary roads provide lifelines to many of our farms and homes, and the rural community has many of the same concerns. While our roads don’t serve as many people or move as much freight as the higher-profile and larger transportation arteries, they are likely the only route in or out of many rural locales and, therefore, can be just as lifesaving in times of need.



With strained state and local budgets, one piece of road maintenance that has become all but extinct in our part of the world is periodic ditch and culvert cleaning by road crews. The result is: A heavy rain event can be left with nowhere to go except where you don’t want it to be.

Like many aspects of road maintenance, culvert cleaning has been mostly transferred to the landowners’ hands. Unfortunately, most folks don’t have the equipment or expertise to perform this task easily; however, there are some tricks to the trade that can assist you if you are left with a dirty or blocked culvert.

The first tip I would share is to evaluate on which end the drainage is leaving. This will be the end to start with, no matter which method of cleaning you employ. Water under pressure is a great way to “mine” materials lodged in the culvert, but you need to be able to get the wastewater out of the way to continue the process.

Building up pressure by banking up water on the intake end of the culvert can be dangerous if you overdo it. Remember: Water has a great deal of weight and power and, even if you were successful in dislodging material plugging the culvert by this method, the resulting suction could unintentionally pull something or someone into the culvert, causing another clog or loss of life.

While we are on the topic of built-up water, I think it is a good idea to assess why the culvert is plugged to begin with. Given the placement, slope or surrounding ground’s ability to produce silt, the best way to repair the culvert is to replace it with a bigger unit on an increased slope from the original.


If you do decide washing the culvert out will work best, the way we rate pressure washers is something to keep in mind. Pressure washer ratings usually speak of two important features: pressure rating (as expressed in pounds per square inch or psi) and volume (as expressed in gallons per minute or gpm).

It is easy to get caught up in the race for more pressure (1,850 psi is better than 1,400 psi); however, high gpm ratings can make the added pressure so much more effective.

As we discussed earlier, more gallons equals more weight. It is easy to imagine being hit with a stream of water from a garden hose isn’t nearly as bad as the same-pressure stream coming from a fire hose. Combining psi and gpm gives the water horsepower. You can increase or decrease the power of the water stream by adjusting either or both.

While insurance, the cost of water and manpower availability can all have a negative influence on getting help with culvert cleanout, your local volunteer fire department can offer assistance by supplying you the necessary water volume and pressure to achieve your goal.

Another option may be no further away than your Yellow Pages. A local company that does sewer line and drainage cleanout can also be a resource, although they will understandably charge you for their expertise.

Mechanical cleanouts are possible but may require some fabricating skills. We actually used this technique to put water and power supply lines under existing roads without digging up the pavement.


Putting together a 2- or 3-inch-diameter pipe greater in length than the culvert, thread a fitting on one end that creates an ever-deceasing diameter until the final piece is a pipe cap fitting that forms the “point” of your pipe spear.

Start the spear into the material plugging the culvert and then, using a loader, backhoe or excavator, apply pressure to the blunt end to push it into the culvert. Once the pipe reaches the other side, you can affix a number of different devices onto the pipe to form a reverse syringe (if you will). As you pull the pipe spear back out, the attachment plungers the material out of the culvert.

Ideas for what to attach to the pipe will hinge on what you have on hand, how long the culvert is, how badly the culvert is plugged and the consistency of the material plugging the culvert. An old tire small enough to fit back down the culvert can work, as can a bucket or barrel reinforced to take the pressure of being dragged back through the culvert.

Once you have the culvert cleaned out, consider once again how the plugging could be prevented in the future. You might add some sort of screening material to the input end. If this is done, make sure the screen is strong enough and big enough not to be pulled down into the culvert and create a new plug itself rather than prevent one.

You might also create a miniature sediment pond at the input end of the culvert by digging out a space below the input. This will allow material to gather below the culvert rather than being pulled into it immediately. This idea will work only if you are going to be faithful cleaning out any buildup in between events, or the basin will become filled, and the culvert will be plugged just as it was before.

As with any farming operation involving weight, pressure and equipment, always practice good safety techniques and think about what could go wrong before learning the hard way firsthand.  end mark

Andy Overbay holds a Ph.D. in ag education and has more than 40 years of hands-on dairy and farming experience.