Development of physically based models for the prediction of desiccation cracks in active clay soils requires fundamental understanding of the mechanical processes which lead to crack initiation on the soil surface and the evolution of the geometrical and topological properties of cracks with time. The major geometrical and topological descriptors of the crack networks include macroporosity, specific surface area, aperture size distribution and connectivity. The evolution of these crack morphology descriptors is a function of clay content, clay mineralogy, pore water chemistry, and drying rate. To investigate effects of these physico-chemical factors on the initiation and evolution of the crack networks, we performed dehydration experiments in conjunction with X-Ray Computed Tomography observations. The 3-D morphological features are quantified based on reconstructed X-Ray CT images with mathematical morphology.