Basic Surveying for Equipment Operators: Part 3

In the first two articles in this series, we discussed how landfill slopes are expressed—as a ratio or percent. We also talked about how to use a hand level, the most basic surveying tool for measuring slope and checking grade.

Unfortunately, some folks criticize the use of a hand level as being very inaccurate. Certainly, it would be difficult to measure to the nearest hundredth of a foot (that’s about 1/8 inch), but in a landfill setting, such tight tolerances are rare. Even so, someone who is skilled in the use of a quality hand level can carry grade very accurately, often within 0.5 percent or so. A hand level’s accuracy is limited by your skill and the precision of the bubble which is usually + about 0.5%. A steady hand and a keen eye are important, but here are some tricks to help you get the most out of your hand level.

First, as previously mentioned, drawing basic sketches of what you’re surveying can be very helpful. By relating everything to horizontal lines—which is what you see when looking through a hand level—you have a good point of reference. Then you can use your sketches to see if you need to move that horizontal sight line up or down in relation to the target. At that point, some simple math will allow you to calculate slope, check grade, etc.

Second, shoot from a solid stance. It’s a given that you’ll be holding your hand level against a grade rod—which will help, but a shaky hand means a shaky bubble. So, you can also use a couple of 4-foot surveying lath (stakes) to form a tripod by grasping them with the same hand that holds the grade rod. This adds stability to a standing shot but locks you in if you can kneel. Of course, if you can brace or lean against a solid object while shooting, that’s even better. The goal is to stabilize your hand level (i.e., your hand) so you can get an accurate reading on the bubble.

Third, keep good notes as you work. Sometimes you'll want to cross-check your current elevation by sighting back down the line at a previous point. By recording the elevation of various points, you’ll have the ability to quickly check your work. Even experienced surveyors will close the loop on their work to reduce the chance of errors.

By now, you're probably thinking that this checking grade business is a bit more work than you had in mind. For virtually every shot, you must measure the vertical distance, then measure the horizontal distance, do the math, and calculate the slope. Sorry to disappoint, but those high school math classes you endured did have a purpose. You need to understand the basic math to perform basic surveying. However, if you find yourself doing lots of slope measurements, there is a tool that can streamline the process. It’s called an Abney Level.

Description automatically generatedAbney levels are simply hand levels with a built-in slope adjustment. Not surprisingly, the Abney level was invented in 1870 by a British fellow named Abney—Sir William de Wiveleslie Abney to be exact. He worked for the Royal School of Military Engineering (RSME)—a group very similar to our own Army Corps of Engineers.

An Abney level has a tube just like a hand level, but the bubble is mounted externally on an adjustable protractor. By adjusting the angle on the bubble to your desired grade, you can simply point and shoot. Conversely, while sighting up or down an existing slope you can adjust the bubble to determine what that existing slope actually is.

These simple tools such as hand levels and Abney levels work well, except when weeds, rough ground, or something else obstructs your line of sight. Say for example when checking grade on something relatively flat, such as a tipping pad or the flowline in a drainage ditch. To see the ground, you'd have to squat down, or even lay on the ground to see a level line, and even then, you may not have a clear line of sight. So, what do you do?

You use a boot. In the surveying world, a boot is a vertical offset that allows you to sight along a line that’s parallel with the ground, but above it. By tradition, we often use a 3-foot boot, because it’s generally high enough above the ground to provide that clear line-of-site. A 3-foot boot is also a good height for kneeling while sighting through the hand level, which allows for a much more stable—and more accurate shot.

But there’s nothing that says you can’t use any other convenient boot height. For example, I know that when standing, my eye is approximately 5.8 feet (70 inches) above the ground. This is useful information because I can simply put a hand level to my eye and know that whatever I’m sighting is 5.8 feet above where I’m standing. I’ve used this many times to approximate the height of a stockpile or slope. By standing at the base of the slope, I look through my hand level, center the bubble, and then sweep across the slope. When I find a visual marker such as a stone or clump of grass, I move up the slope, stand on that marker and repeat the process. I am essentially measuring the height of the slope in 5.8-foot increments. The last fractional measurement may be an estimate, but those cumulative measurements will provide a pretty good estimate of the total slope height. You can work your way downslope in the same way by simply putting a visual marker where you're standing, or even kicking a notch in the slope that you can sight back to as you stair-step down the slope.

The purpose of boots is to provide a clear, convenient line of sight when measuring grade. When I worked as a heavy equipment operator—yes, it was a long time ago, and no, we don’t need to get into the details—I would often set grade stakes based on an equipment boot. The vertical offset I used varied based on the size of the machine I was operating at the time, but it always equaled the height of my eye above the ground as I sat in the operator's seat. If my eye was 9.2 feet above the ground, then I’d set grade stakes that were booted 9.2 feet above my target grade. That way, I could stop the machine, take a quick shot, and know how much I needed to cut or fill. I could do all of this from the comfort of my seat without getting off/on the machine. I thought I was pretty smart, but maybe I was just lazy. If different operators will be using operating your tractor with the same boot, just put a mark on the ROPS to ensure everyone is using the same point of reference.

The last type of boot we’ll discuss is a lift boot, kind of a visual sight for putting in the next lift of waste. Let’s say we want to put in a 10-foot lift. Further, we’ll be using a 9-foot equipment boot. That’s a 9-foot boot, above a 10-foot lift of trash—a total of 19 feet. So, out in front of our advancing fill, we need a series of markers that are 19 feet above grade. Remember, this approach works for any lift depth or equipment boot. This is just an example.

Here’s the plan. Get one or more metal T-Posts and drive them into the ground where the new lift will go. A 50-foot grid pattern works well. Then get several 20-foot pieces of 2-inch PVC pipe. You always want something taller than your total height (lift + boot), which means you'll sometimes need to add a bit more to your 20-foot stick. Lay it out on the ground, measure 19 feet from one end, and then mark that point with brightly colored paint or ribbon. Pick up the PVC pipe and slide it over the T-Post. Once it’s standing upright, you have a 19-foot boot that all operators can use as a target.

Yes, this can be a bit more complicated if you have to factor in the cross-slope of the next lift, but if you sketch it out…you can figure it out.

As we wrap up this three-part series on surveying for equipment operators, I’d like to share another simple tool that equipment operators find very useful when making a slope. It’s called a Slope Meter, and is manufactured by—you guessed it—Slope Meter, Inc. This simple device can be attached to your machine on the dashboard, as shown here. In this configuration, it can show you the cross-slope. Or it can also be placed on the side of the machine to show the fore/aft slope. Of course, you could place two, then you’d be ready for any slope. They also manufacture an electronic version.

Every day, landfill operators add another building block to the landfill, and every one of them must be built to the correct slope and elevation. Somebody must do that surveying, and if you’re an equipment operator, that “somebody” is you.

So, get a hand level, practice with it, and you’ll be a step above those other operators who just push trash.