What is a riverside auger?
A riverside auger is a hand soil auger for hard, stiff or gravelly ground, recognisable by two sharply ground points angled downwards at the foot of the auger body. It is the tougher relative of the familiar Edelman auger and is used for site investigation, installing monitoring wells and taking soil samples — including below the water table.
How it is built and how it works
The body is an open, half-round tube with two spoon-shaped blades beneath it, joined by a bridge. The points project downwards at an angle. As the auger turns, those points cut the soil loose; the loosened material is pushed up into the open tube. Because the blades are set slightly proud of the tube, friction against the borehole wall stays low and the auger keeps turning freely.
That is exactly where the difference lies: an Edelman auger stalls in dry, hard clay or in gravel because it finds nothing to bite on, whereas the riverside auger digs its points in.
Where it is used
- Hard, desiccated clay and loam, where an ordinary auger will not advance.
- Gravelly and sandy ground, including river levees and alluvial deposits — hence the name.
- Boring under water or below the water table, for instance from a staging.
- Punching through a hard layer so that another auger type can continue below it.
Practical tips
- Work with a set. In practice you often start with an Edelman auger and switch only when you reach a hard layer. The heads generally fit the same extension rods and the same cross handle.
- Turn, do not push. The auger cuts by rotation; excessive downward force jams the points and bends the bridge.
- Withdraw regularly. A full tube stops cutting. Lay the arisings out in order beside the hole so you keep track of the soil profile with depth.
- Keep the points sharp. Blunt points are the most common reason a riverside auger “stops working”.
- Check notification rules. Ground investigation boreholes are subject to notification or permitting in many jurisdictions, particularly where an aquitard would be penetrated.
Related terms
- Hand auger
- Edelman auger
- Groundwater
- Soil
- Site investigation
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