Australian Dictionary of Biography

William Hogarth Robertson Nimmo (1885-1970), hydraulic engineer, was born on 10 February 1885 at Torquay, Devon, England, son of William Henry Nimmo, a Scottish-born civil engineer, and his Victorian-born wife Emma Margaret, née Robertson; his parents had left Australia on a world tour. Educated at Cumloden school, East St Kilda, and the University of Melbourne (B.C.E., 1908; M.C.E., 1924), young Nimmo gained experience as a draftsman and engineering surveyor in Victoria, New South Wales and Queensland. In 1913 he joined the Tasmanian Public Works Department. His work included the design of a concrete-arch dam and a reinforced-concrete bridge.

Transferring to the Hydro-Electric Department in 1918, Nimmo studied the hydrology of the Great Lake and, as resident engineer, oversaw the building of the Liawenee diversion canal from the Ouse River to the lake. He also began a lifelong practice of using investigations at construction sites to solve theoretical design problems. The thesis he wrote for his M.C.E. drew on the experience he gained in Tasmania. In 1924 he moved to Brisbane as civil engineer to the Metropolitan Water and Sewerage Board. At St Cuthbert's Presbyterian Church, Brighton, Melbourne, on 17 December that year he married Alice Emily Clark.

In 1927 Nimmo became designing engineer with the Queensland Main Roads Commission, then in its formative years under (Sir) John Kemp. He served (from 1933) on a Bureau of Industry committee which investigated Brisbane's water-supply and flood-mitigation requirements, completing the investigation almost single-handed in about fifteen months. For the economic assessment he derived flood-probability data and unit-hydrographs which he used in conjunction with the flood plan of the city. His efforts led to the establishment in 1934 of the Stanley River Works Board to build the Somerset Dam on the upper reaches of the Brisbane River. He was seconded to the board, initially as designing engineer and later as chief engineer (1935-49). Innovations in design and construction included measures to prevent hydraulic uplift on the base of the dam, and hydraulic models to test the performance of the dissipator and sluice-gates.

When work on the dam ceased during World War II, Nimmo chaired the board of engineers which managed the building (1942-44) of the Brisbane Graving Dock at Colmslie. The board employed personnel and plant from the Stanley River Works Board, the Main Roads Commission and the Department of Harbours and Marine, as well as additional labourers from the Civil Constructional Corps. After the war Nimmo and his staff (who at that time made up the hydraulics branch in the office of the co-ordinator-general of public works) investigated the hydrology of the Channel Country in the south-west of Queensland, and the possibility of scour at the site of the new Burdekin River road and rail bridge. They also conducted a feasibility study of the Burdekin irrigation, hydro-electric and flood-mitigation scheme, designed and took charge of construction of the Tully Falls hydro-electric project, and resumed work on the Somerset Dam in 1948.

On 24 November 1949 Nimmo was appointed commissioner of irrigation and water supply. He held office during a period of increased activity which saw the construction of the Tinaroo Falls Dam and works associated with the Mareeba-Dimbulah irrigation scheme. At the same time he was either chairman or a member of numerous interdepartmental commissions and boards. An engineer-scientist who based his designs and building techniques on sound theoretical understanding and wide practical experience, he had an unassuming manner, but was definite about what he wanted and adept in devising new approaches to problems of investigation and construction. He gained the confidence, admiration and affection of his staff, and was always ready to provide a useful reference. In 1964 the University of Queensland awarded him a doctorate of engineering for his published work.

A foundation member (1919) of the Institution of Engineers, Australia, Nimmo was chairman (1937) of the Brisbane division, and a national councillor (1938-58) and president (1948). He won the institution's (Sir) Peter Nicol Russell medal in 1950 and was elected an honorary member (fellow) in 1960. In 1956 he was awarded the W. C. Kernot medal by the University of Melbourne. He led the Australian delegation to the congress of the International Commission on Large Dams, held in Rome in 1961. In the following year he was appointed C.B.E.

Nimmo had retired from the public service in 1955, but was retained as engineering consultant to the Queensland government and continued to serve as chairman of the Dumaresq-Barwon Border Rivers Commission. He died on 7 May 1970 in South Brisbane and was cremated; his wife, daughter and son survived him.