Gravel & Asphalt Driveway Washout: Repair & Prevent in Oregon

Rebuilding the Same Washout Every Winter Gets Old

If you own a rural Oregon driveway, you know the routine: a big winter storm, and the gravel that was on your drive is now in a gully at the bottom of it. You haul in more rock, grade it smooth, and wait for the next atmospheric river to do it all again. Washouts feel inevitable, but they're not. A driveway washes out because water is running where it shouldn't, and once you fix the water, the washouts stop.

This guide covers both halves: repairing the damage and preventing the next one. For the broader drainage picture, see our Oregon drainage guide.

Why Driveways Wash Out

A washout is erosion, and erosion needs moving water. The usual culprits:

• Water running down the driveway surface instead of off it, because the drive is flat or crowned wrong, picking up speed and carrying material away.
• No roadside ditch, so water that should run alongside the drive runs on it.
• An undersized or blocked culvert, which causes water to back up and overtop the driveway, washing out the crossing.
• Concentrated runoff from uphill dumping onto the drive with nowhere to go.
• Loose, uncompacted material that moves easily once water gets going.

Repairing without addressing these just resets the clock. The fix is to control where water goes and how fast.

Repairing a Washout

The repair depends on severity:

• Surface erosion and rutting — regrade the driveway, bring in and compact fresh base rock, and re-establish the proper crown or cross-slope so water sheds off rather than running down.
• A gully or channel cut across the drive — rebuild the failed section with compacted base, and address the water source that cut it, or it will cut again.
• A washed-out culvert crossing — clear or replace the culvert, rebuild the fill over it, and armor the inlet and outlet against the next storm. Our sizing a driveway culvert guide covers getting the culvert right.
• A full base failure — where the sub-base is gone, rebuilding means excavating and reconstructing the road section, not just adding rock on top.

Proper compaction is key throughout. Loose material is what washes away; a well-compacted base with the right rock holds together far better.

Preventing the Next Washout

Crown the Driveway

A driveway should shed water off its surface, not channel it. Crowning — building the center slightly higher than the edges — sends water to both sides where it can run off into ditches instead of down the drive picking up speed. For drives on a grade, the right cross-slope directs water off to the downhill side. This single detail prevents a huge share of surface washouts.

Build Roadside Ditches

A ditch alongside the driveway gives water a place to run other than the road surface. It catches runoff from the drive and from uphill, and carries it to a safe discharge point. On sloped rural drives, ditches are essential — without them, the driveway becomes the channel.

Size and Maintain Culverts

Where a ditch or seasonal flow crosses under the drive, a culvert carries it through. An undersized culvert backs water up and overtops the drive; a blocked one does the same. The culvert has to be sized for the flow it sees and kept clear of debris. A headwall and armored inlet/outlet protect the crossing.

Armor the Vulnerable Spots

Where water concentrates and moves fast — ditch outlets, culvert ends, steep sections — armoring with rock (riprap) absorbs the energy and stops erosion before it starts. It's far cheaper to armor a known problem spot than to rebuild a washout there every year. Our erosion control excavation guide covers these techniques.

The Rural Oregon Reality

Long gravel drives on sloped, wooded rural lots are the classic washout candidates — steep grades, lots of uphill water, and a soft surface. The solution is rarely just more rock. It's a system: crown the surface, ditch the sides, culvert the crossings, and armor the hot spots, so water is managed end to end rather than left to find its own path down your driveway. Get that system right once and the annual rebuild becomes a thing of the past. For paved-drive specifics, see our driveway drainage solutions guide.