How to Measure the Slope of Land. You may need to measure the slope of land for home construction, designing a site for future construction, farming or working on other projects. Here are some steps you can take to properly measure the slope of land.
Use a line level, which is two poles of the exact same height (50 inches would be good) with string running between the poles. At the exact center of the string, a level is suspended. There are also notches at the exact same interval in each pole. Have one person stand on the slope holding one pole and the other person stand exactly down the slop from him holding the other pole with string running through the top notch.
Make the string level. The person at the top of the slope should move the string to the different notches on his pole until the level suspended from the middle of the string shows a level setting.
Calculate the slope by measuring the distance from the notch where the string was placed to the top of the pole. Slope is a percentage, meaning the number of units falls or rises in 100 units of horizontal distance. Every inch from the top of the 50-inch pole equals 2 percent of slope (with the top of the pole being originally level with the second pole, showing a 0 percent grade). The lower the string must be on the pole to be level, the higher the percent of slope. A notch 4 inches down the pole indicates an 8 percent slope and a notch 8 inches down the pole indicates a 16 percent slope.
Use another method of measuring slope with just one person. With a stick that is 50 inches long, a level, a pencil and a yard stick, stand on the slope holding the yard stick upright.
Place the stick on the slope, and hold the level on the end of the stick nearest you. Raise the stick until it is level.
Mark the height on the yard stick where the 50-inch stick is level. Measuring from the ground up, determine the height necessary for the 50-inch stick to be level.
Measure the slope of the land by multiplying the height from the ground required for level by two. This figure will be your percent of slope.