In KAUST-Perimeter Security Systems project, the purpose of the ditch is to provide a physical barrier for the intruders, vehicles or pedestrians. To avoid ponding of water inside the ditch and discourage associated lift stations, to stay higher than the water table and to refrain from sloping the ditch bed to direct water towards prescribed exists, the ditch design was modified. The new design keeps the ditch bed higher than the water table, and lets the rainwater percolate through the bed at a certain percolation rate so that ponding of water is not allowed. The ditch design does not allow water to seep upwards from the bed or from side walls into the ditch, which will cause permanent ponding of water and defeat the purpose of the modified design. Only rain data and cross section of the ditch were used to calculate the percolation rates and seepage from sides was not considered for designing the desired percolation rate of the ditch bed.

Keeping in view the above mentioned basic assumptions behind modifying the ditch design, ICC is urged to ensure that no hydraulic gradient is created and water is not allowed to seep into the ditch from sides or from underneath. If the modified design criteria cannot be met, ICC shall consider designing the ditch according to the project proposal. 

Should you have any questions, please contract Fahad A. Al-Balawi, Sr. Project Engineer on Tel. No. +966 12 422 4393.
