Augustus Edward Darvall spent some time during the eighteen-nineties in San Rey (near San Diego), California, to where some of his English cousins had emigrated. During the Anglo-Boer War (1899-1902) he served as an officer in the British armed forces. In June 1901 he was promoted from lieutenant to captain and subsequently was awarded the Queen's South Africa Medal.
After the war Darvall moved to Australia, where he became manager of the Moree irrigation farm in New South Wales. He described the farm and the work done there in an article, "Moree irrigation farm", published in the Agricultural Gazette of New South Wales (September 1910, pp. 802-809). That same year W.R. Fry and he published Irrigation with artesian water (New South Wales Department of Agriculture, Farmers' Bulletin No. 33, 1910, 38 pp).
Darval then returned to South Africa and worked as an experimentalist at the School of Agriculture at Elsenburg, near Stellenbosch, where he participated in crop and pasture research during 1915-1917. During the early nineteen-twenties he resided in Bloemfontein.
In June 1903 he married Alice Maud Coaton in Wellington, Western Cape. He was survived by his wife, two sons and a daughter.