aqueducts no relation Roman engineering
Civilian engineering by military troops
The Roman army also took part in building projects for civilian use. There were sound reasons for the use of the army in building projects: primarily, that if they weren't directly engaged in military campaigns, the legions were largely unproductive, costing the Roman state large sums of money. But the involvement of the soldiers in building works, kept them not only well accustomed to hard physical labour, but also kept them busy, since it was the widely held belief that busy armies weren't plotting to mutiny, whereas idle armies were.
Of both military and civilian use was the construction of roads within the boundaries of the Empire, in which the army was heavily involved. But so too were soldiers put to use in the construction of town walls, the digging of shipping canals, the drainage of land, aqueducts, harbours, even in the cultivation of vineyards. In some rare cases soldiers were even used in mining work.
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