Chart Datum is the reference datum used in the Hong Kong waters for various marine activities including navigation and civil engineering works. It is 0.146 metre below the Principal Datum of Hong Kong.

If you find that the sea at the waterfront of your lot is becoming so shallow that vessels are finding it increasingly difficult to anchor there, an application should be made direct to the Director of Marine who will request the Chief Engineer, Port Works of the Civil Engineering and Development Department to carry out investigation. Any dredging approved by the Marine Department will be either carried out by you or by Government depending on the lease condition.

All shallow water reports should be directed to the Director of Marine who, if necessary, will request the Chief Engineer, Port Works of the Civil Engineering and Development Department to carry out investigation and dredging work.