• Land subsidence and pavement settlement. It is essential for the AOT personnel to measure the pavement elevations periodically, so that the unnecessary ponding in the airfield pavement can be avoided. Apart from the measuring the settlement of the airfield pavements, the rate of land subsidence of the airport site should also be measured by setting up reference points in non-loading areas, such as original ground at various locations around the airport site. The relative settlement of the pavement and the surrounding areas would be useful in the water level management of the canal system within the site.