The first step consists in dividing the gully into homogeneous sections in terms of slope and cross section (For example, in four sections. figure. 1).
At least one section will have to be entered and the maximum will be 10 sections.
Next, each section should be defined by its longitudinal and cross section profiles. For the longitudinal profile, the farmer needs to measure the projected length and the stream longitudinal steepness (slope) of the gully bottom (figure 2).
The projected length of the gully could be obtained from the real length of the gully and the elevation difference at the upper and the lower edge of the section as shown in figure 2 (equation 1). Alternatively, it could be obtained from the real length and the steepness of the section (figure 2, equation 2).
If the length of the gully is difficult to be measured at field, the projected length could be directly obtained from Google Earth using the measuring tool or in a SIG (i.e., QGIS, ArcGIS…).
For the cross-section profile, farmers need to measure the depth and the width at the bottom of the gully with a regular tape, and the side steepness at the lower and the top sub-section with a clinometer (figure 3).
Cross sections in each stretch are assumed to be symmetrical. All field measures could be made with a measuring tape and a level or a clinometer or, with the help of GPS device. There are also a number free apps for mobile devices that could be helpful for these field measures (see the links below).