Southern Africa's first Industrial Development Zone is taking shape near the city of Port Elizabeth. The Coega IDZ is a purpose-built industrial estate for local and international industrial developers. The new international deepwater port of Ngqura forms a vital component of the Coega IDZ. Its three mass concrete quay walls were constructed in a dewatered excavation on the beach next to the Coega River mouth.

This paper presents the design, installation and performance of the dewatering installation with specific focus on implementation of the observational method. A major challenge for the dewatering design was the timely draw down of resident water levels in two distinct aquifers ahead of the earthworks operations – the first quay had to be operational within 88 weeks. This was achieved through a combination of a cut-off against the sea, perimeter deep wells and surface pumping. Problem areas were dealt with by well pointing to stabilise excavation sidewalls and to locally control elevated seepage.