Technical Abstract: Soils and sediments consist of granular particles with an intricate network of pores in between. The structure and orientation of these pores will determine how the material transports fluids and contaminants. A common practice in soil science to simplify experiments and to achieve a homogeneous medium against which to test transport equations is to repack a 2D (Hele-Shaw cell) or a 3-D column . Soil is broken up and sieved to remove large particles that could cause anomalous measurements and then it is repacked into the column. However, this procedure destroys the natural structure and imparts a new structural arrangement. The material may appear to have similar bulk properties such as bulk density and porosity but as we aim to demonstrate the structural properties will be a function of the method used to repack and are unlikely to achieve a uniform distribution at the micro-scale. Results in these experiments demonstrate how mixtures of particles of different sizes segregate when poured, forming banded structures. The rate at which a material is poured will determine the uniformity of the grain size distribution.