He played a central role in the recovery efforts following the inundation of Walcheren in 1944, and the works to repair the significant damage caused by the North Sea flood of 1953.
After graduation, he joined Rijkswaterstaat (the Dutch Directorate-General for Public Works and Water Management), where he was employed in the Studiedienst (Study Department) of the Directie Benedenrivieren (Directorate for the Lower Rivers).
[6][7] Ferguson was deeply involved in the design and construction of the Haringvliet sluices, which were critical for water flow regulation and flood protection in the Rhine-Meuse-Scheldt Delta.
[8] He also contributed to the closure of tidal inlets including the Haringvliet and Brouwershavense Gat, major Delta Works schemes which were required to ensure that flood risks were mitigated.
[12] Ferguson was awarded the Order of the Netherlands Lion,[13] and his contributions to the scientific underpinning of the Delta Works Plan earned him an honorary doctorate from Delft University of Technology in 1987.