Wenbin Zhou

Zhou Wenbin left this world on the morning of Qingming, the day Chinese families sweep their ancestors' tombs, and his family took it as a sign that he had simply gone to join the conversation. Born in Suzhou in 1932, into a household of silk merchants who expected him to inherit the shop, he preferred canals to ledgers and spent his boyhood floating paper boats down the Pingjiang River and timing how fast they arrived.

In 1950 he entered Tsinghua University to study hydraulic engineering, and he never really left. Over forty-three years in the Department of Hydraulic Engineering he taught open-channel flow, built scale models of Yellow River floodplains in the laboratory's long concrete basin, and advised engineers on irrigation and reservoir projects across northern China. The Cultural Revolution sent him to a May Seventh Cadre School in Jiangxi for three years to farm and dig ditches; he never spoke bitterly of it, remarking only that the ditches there were very well designed. Back at Tsinghua he supervised more than a hundred graduate students, many now senior engineers, and answered every letter with a fountain pen.

At home in a Tsinghua faculty apartment he drank Longjing tea from a chipped enamel mug, practised tai chi on the lawn at six every morning, and on winter afternoons taught his grandson xiangqi, losing on purpose, badly. He and his wife, Liu Shuqin, a paediatrician at Peking Union Medical College Hospital, were married for fifty-eight years. He died quietly on 4 April 2021, aged eighty-eight. He is survived by Shuqin, his daughter Zhou Lan, his son Zhou Yang and two grandchildren, and by a laboratory basin that still holds, in faded pencil, the date of every experiment he ran.