These represent dispursion in a uniform material, such as soil. The above image was created using an Excel Spreadsheet. Gravity is the prime factor in the movement of groundwater from higher locations to lower. However other factors contribute. The rock material can retard and divert flow.
Cracks can produce rapid flows.
Exit points such as springs, lakes, streams or pumping locations can draw water towards those locations. As the groundwater flows, the pollutants follow the flow and spread out. These images were created from an Excel spreadsheet similar to the process described in the link below. Click here to view instructions for making spread sheet models and charts.