Manning, Robert (1816–97), surveyor and civil engineer, was born 22 October 1816 in Avincourt, Normandy, France, third of eight children of William Manning (1783–1826) of Knocknamohil, Co. Wicklow, a lieutenant in the Wicklow militia who fought in the USA, in the Peninsular war, and at Waterloo, and his wife Ruth (1792–1854), daughter of Lionel Stephens of Dromina, Co. Waterford. Little is known of Manning's first thirty years except that he was privately educated in Kilkenny and Waterford, and that when his father died, his family settled in Ruth's ancestral home in Dromina (1826). This house, near Passage East, is still standing and still lived in. For many years Manning worked for his uncle John Stephens, doing the accounting, surveying, and valuations for the family estates in the south and west of Ireland (1834–45). During this time he received practical training in civil engineering under a Mr Muckleary, the farm steward, and became an engineer in 1848.
With the implementation of the government's arterial drainage scheme, Manning was employed by the office of public works in Co. Louth, working first as a clerk (January–October 1846), but was soon promoted to assistant engineer (October 1846) and then district engineer for Ardee and Glyde (January 1848). By the mid 1850s the drainage works were coming to an end, so Manning was forced to find new employment. In 1856 he was hired by the 4th marquis of Downshire to complete a topographical survey of his 120,000 acres of land in Co. Down, Co. Wicklow, and King's Co. (Offaly) (1856–8), and the end result was a truly superb set of estate maps. Manning continued as the marquis's engineer-surveyor for the next thirteen years, engaging in arterial drainage, water supply, and bridge and harbour work. Unfortunately, when Downshire died Manning again found himself unemployed, for the new marquis felt that he could not afford his own personal engineer (August 1869). That same year Manning once more joined the OPW, this time as second engineer (2 August 1869–1874), but was soon promoted to chief engineer (1 April 1874–1891). In this capacity, Manning worked tirelessly on all matters relating to harbours: he rebuilt an entire royal harbour and maintained 200 fishery piers and harbours, of which he designed and oversaw the construction of nearly 100; he also worked on railways, country roads, sewerage systems, water supplies, and inland navigation, and supervised extensive improvements to the River Shannon and the impoundment of Lough Allen. Although he enjoyed his profession, Manning found the post of chief engineer particularly difficult because of long periods spent away from home, a pitifully small staff, and the mere nine days leave a year he received. In 1878 he complained to a committee appointed to inquire into the operation of the OPW, but his complaints resulted in little improvement. In 1891 a law was passed prescribing 65 as the mandatory retirement age; at the time he was 75, so he agreed to retire at the end of the year.
Manning had joined the ICEI in 1848 as an associate member and became a full member in 1856, eventually serving as both vice-president (1876) and president (1878–9). He frequently gave papers on various topics, but his most monumental contribution was his paper ‘The flow of water in open channels and pipes’, which he presented at a meeting of the ICEI in December 1889 at TCD. On this historic day, Manning introduced his formula for the calculation of open channel flow, a problem hitherto believed to be mathematically indeterminable. The ‘Manning formula for open channel flow’, as it is known worldwide, is still used at present. He was a member of the Friendly Brothers of St Patrick (from 1839) and London's Institution of Civil Engineers (elected 7 December 1858) and was said to have been a fine horseman, an enthusiastic fisherman, and an accomplished flute player. Manning and his family lived for a time in Co. Louth and at Dromantanty near Hillsborough, Co. Down, but permanently settled in Dublin in 1870. He died in his home at 4 Upper Ely Place on 9 December 1897 and was buried in Mount Jerome cemetery. His portrait now hangs in the Institution of Engineers, Dublin.
Manning married (7 March 1848) Susanna (d. December 1894), daughter of George Gibson (1768–1848) of Dublin, in St Patrick's church, Waterford city. They had four sons and four daughters, of whom seven survived into adulthood; of the daughters, three were artists and one a musician. His second daughter, Mary Ruth (‘May’) Manning (1853–1930), landscape and figure painter, was born in Dublin. She was an artist of some accomplishment, having studied in Paris during the 1870s with Louise Breslau and Sarah Purser (qv). Her medium was oil and watercolour, and during the period 1880–92 she exhibited in the Royal Society of Artists, Birmingham; the Walker Art Gallery, Liverpool; the RHA, Dublin; and Brussels. Save for a brief period spent in Hampstead, London (1889–92), May permanently settled in the family home on Ely Place in 1880. She and one of her sisters ran a studio that offered art lessons for young girls not eligible to enter the RHA; May encouraged many of her students to study in Paris and played a prominent role in the development of several female artists at the turn of the century, including Mary Swanzy (qv). Teaching took precedence over her own work, hence the infrequency of her exhibitions; but she continued to practice her craft and in 1885 became a member of the Dublin Sketching Club. Neither she nor her sisters ever married; May lived with her father till his death, and remained in his home for several years after before settling (1905) on Winton Road, Leeson Park, Dublin, with at least two of her sisters, where she died on 27 January 1930. Her oil painting of a landscape and setting sun hangs in the NGI and her ‘Study of a boy’ (also in oil) in Dublin City Gallery (The Hugh Lane).