This soil is under a rectangular concrete slab, $15m45m$ used as a foundation for a building. A water pipe, $100$ mm diameter, is located in a trench $450$ mm below the center of the slab. The trench, $300$ mm wide and $450$ mm deep, running along the length of the slab, was backfilled with the same soil. If this pipe were to leak, what effect would it have on the foundation? Draw a neat sketch of the existing trench and pipe, and show in another sketch how you would mitigate any water issue related to the pipe and the soil. Explain why your mitigation method is better than the existing construction.