Theodor Christoph Heinrich Rehbock, a German civil engineer, was the son of Alexander Rhebock and Emma Katharine Elisa Schöffer. He studied at the Technical Universities in München and Berlin from 1884-1890 and qualified as a civil engineer in 1892. Early in his career he made a contribution to the theory of arched bridges with his paper, "Beiträge zur theorie der versteigter Bogenbrücken" (1892). However his main interest was in the study of large water management projects. In 1899 he was appointed as professor of hydrology at the Technischen Hochschule (Technical University) of Karlsruhe, a post he held to his retirement in 1934. He soon established the Flussbaulaboratorium (water works laboratory) as part of the Department of Civil Engineering, where water management projects from many countries were tested by means of models. One of these projects was the construction of the Afsluitdijk and the huge Zuiderzee polder system in the north of the Netherlands (1931). The laboratory, which he directed until his retirement, was later named after him. He introduced various innovations in the study of water management and also conducted field studies, and to this end visited North and South America, Turkey and southern Africa. He was awarded honorary doctoral degrees in engineering in München and by the Palatin Joseph University in Budapest.
In 1896 Rehbock was appointed by the Syndikat für Bewässerungsanlagen in Deutsch-Südwestafrika, established in 1895, to lead an expedition to German South West Africa (now Namibia) to study its water resources and their scientific exploitation. The expedition, which included J.C. Watermeyer* of the Government Analytical Laboratory in Cape Town, spent eleven months in the central and southern parts of the territory, from October 1896 to September 1897. Rehbock described his findings and recommendations in a book, Deutsch-Südwest-Afrika. Seine wirtschaftliche Erschliessung unter besonderer Berücksichtigung der Nutzbarmachung des Wassers (German South West Africa. Its economic development with special consideration of the utilisation of water; Berlin, 1898, 237 pp., with maps, plans, etc). The book contained a very fine presentation of the territory's water resources and their development, ground water extraction, the supply of drinking water, and related topics. Most important, however, were Rehbock's detailed proposals for the construction of six dams, four near Windhoek and two in the south of the territory, including proposals for how their construction should be financed. He urged especially that an immediate start be made with a large dam and associated agricultural scheme at Hatsamas, some 80 km south-east of Windhoek Three of his proposed dams were eventually built, that at Hatsamas and those now known as Hardap Dam and Neckartal Dam (the latter was completed only in 2020).
Other publications resulting from his expedition included an album of 96 photographs taken during the expedition (1898), a paper on the settlement of German South West Africa (1900), and a report on its agriculture (1901-1902). In 1905 he contributed two papers (in French) to the meeting in Rome of the International Institute of Political and Social Sciences Concerning Countries of Differing Civilisations. These dealt with the utilisation of water in subtropical countries, and methods of irrigation in the arid parts of southern Africa, and were also largely based on his experience in Namibia.
