A culvert lets water pass under a driveway or crossing. We dig the crossing, set the pipe on a firm bed at the right grade, and backfill and compact over it so it carries traffic and keeps the water moving.
Culvert Installation in Boise and the Treasure Valley
Anywhere a driveway, lane or field entrance crosses a ditch, the water needs somewhere to go. A culvert is a pipe under the crossing that does that job. When it's the wrong size, set at the wrong height or crushed by a loaded truck, water backs up, floods the upstream side and can wash out the crossing.
We install and replace culverts for homeowners, farmers and builders around Boise, Star, Kuna, Middleton, Parma, Homedale, Nampa and Caldwell.
When You Need a Culvert
- A new driveway or lane crosses an irrigation ditch or roadside ditch
- A farm or field crossing needs to carry equipment over a ditch
- An old culvert is crushed, rusted through or buried in silt
- Water ponds above a crossing because the pipe is too small
- A swale or drainage channel crosses a driveway
Who Decides the Size and Type
This is the part to figure out first. If the ditch belongs to an irrigation district or a ditch company, the owner usually has a say in pipe size, material and how it's set. If the crossing is along a county or highway district road, the district or county may have rules for size and for the driveway approach. The pipe also has to be big enough for the highest flow, not the average one.
We ask who owns the ditch at the estimate. If it isn't yours, we want their approval in hand before we buy pipe. Our ditch digging page covers more on easements and getting their OK.
Digging and Setting the Pipe
We dig the crossing wide enough to work in and to the right depth. The bottom needs a firm, level bed, and any soft spots get dug out and replaced with compacted material. The pipe goes in at the same grade as the ditch, so water doesn't pool at the inlet or run too fast at the outlet. Joints get connected as the pipe maker calls for, since a gap can wash out the dirt around the pipe.
Common culvert pipe is corrugated metal, plastic or concrete. The material depends on what the ditch owner or road authority wants, how much water it carries and how much weight goes over it. We can install what's specified, or help you pick one if there are no rules.
Backfill, Cover and Compaction
The sides of the pipe are the hardest part to get right. Backfill goes in a layer at a time and gets compacted along both sides, so the pipe is supported all the way around. Too little cover over the top and a loaded truck can crush it, so the pipe needs enough dirt or gravel above it to spread the weight. Pipe makers list minimum cover for each size and type, and we follow it. See our soil compaction page for how that works.
Protecting the Ends
The inlet and outlet take the beating. We let the pipe stick out past the edges of the driveway so the ends are easier to find and clear. Rock around the outlet slows the water so it doesn't dig a hole, and rock at the inlet keeps the bank from washing around the pipe. Headwalls and wing walls are options on bigger crossings. Our erosion control page explains how rock and grading protect those spots.
Working Around Water
Most ditches carry water during irrigation season, roughly April to October. The best time to replace a culvert is when the ditch is dry, in fall after shutoff or in early spring. When a ditch can't be shut off, we plan a way to move the water around the work, and we'll tell you if the job needs to wait.
Replacing an Old Culvert
An old culvert may be rusted through, crushed at the ends, buried in silt or too small for the water it now carries. We dig it out, check the ditch grade, and replace it with the right size and set it at the right height. Sometimes the crossing also needs regrading so water doesn't run down the driveway into the pipe. See excavation for driveways.
Why Call Ultimate Excavation LLC
We're an Idaho registered contractor (RCE-65836) based in Caldwell, with a 5.0 rating on Google. Our reviews describe us as professional, on time and careful with their property. Call (208) 697-2429 or request a free estimate. Tell us who owns the ditch, how wide the crossing is and what drives over it.
