Retiring with the honorary rank of Colonel, on his way home he was summoned to Cairo to meet
Lord Dufferin who offered him "the keys of the Nile" – the position of Director of Irrigation for Egypt, then still nominally part of the Ottoman Empire, but in practice controlled by the British. His first priority was the
Nile Barrage, designed to retain water to irrigate the Delta, which had been built at great expense between 1843 and 1862 but soon abandoned when cracks appeared in its structure. Scott Moncrieff arranged for a trial closing of the gates allowing a limited operation, while carefully monitoring the cracks. The results were so successful in terms of improved agricultural yield that he was able to ask for, and get, a million pounds for a complete repair and strengthening of the Barrage, which was carried out between 1885 and 90. Over a period of nine years he reorganised the whole irrigation system and "was so successful in improving the whole irrigation system that Egypt, from being a bankrupt country, became comparatively flourishing". For his work in Egypt he was appointed KCMG. == After Egypt ==