خزان أسوان
In 1897 he left the family firm to become an Assistant Engineer at Kennedy and Jenkin, working with Alexander Kennedy, the famed electrical engineer and another keen climber, and worked within his consultancy. He was made a partner in the business in 1908 and became the senior partner in 1934 on the retirement of John MacFarlane Kennedy, son of the founder. Donkin worked heavily in hydro-electric power and was involved in several large scale projects. Amongst these were the Aswan Low Dam on the Nile in Egypt which was built between 1899 and 1902 and the Owen Falls Dam on the White Nile in Uganda which was started in 1947 and finished two years after his death.