Wherever man has built over nature, soakaways serve to absorb rainwater in a controlled manner as part of the natural water cycle. Water from roofs, streets, squares and all sealed surfaces is drained into individual septic tanks or into a network of rainwater channels and soakaway shafts.
Over the course of time, especially after heavy rainfall, soakaways can become heavily silted up by the dirt from surface drainage. Then large amounts of water seep away only slowly or not at all. The result is overflowing and flooding.