In areas surrounding the city of Burdur, Turkey, where water contents are high, no swelling-shrinkage-dependent deformations are visible because the active zone depth is adjacent to the surface. There are some deformations in areas with low water levels, especially those with low-rise construction. Thus, in some areas around Lake Burdur, increased swelling-shrinkage-dependent deformation is inevitable owing to a steadily decreasing water level of the lake. However, development around Lake Burdur, such as an organized industrial area, a civilian airport, and a military airport currently under construction, exacerbates the problem. Therefore, we examined swelling potentials of lacustrine clay in the active zone within a selected area around lake. Lacustrine soils in the selected area were studied using a hand auger, with a total of 379 samples at 50 points, through depths of 1-3 m. Clayey levels in the research area were separated into three different clay-clayey levels and were analyzed by X-ray diffraction and scanning electron microscope. Results showed that clay minerals at all levels averaged 39-52 % and that most were smectite group clays. Microstructures were plate-like and were aligned face to face. It was also determined that swelling potentials of all examined clayey levels were high to low, with change between 0.22 and 2.59 % and swelling pressures between 2.9 and 71 kPa. Because the water level was close to the surface, so was the active zone; therefore, deformation was noticeable. Swelling-shrinkage-dependent deformations are inevitable in the future with decreasing lake water level.