Castellum Aquae
The castellum aquae (plural: castella aquae) were reservoir tanks located at the terminus of a Roman aqueduct. The name literally means ‘water fortress’ in Latin. The castellum acquae served a purpose beyond simply acting as a water reservoir at a terminal point of an aqueduct branch. With the water pressure created by the running water of an aqueduct, it was also necessary to slow the water and reduce the force generated by the water before it was dispersed into smaller pipes and channels to be used in the water network of the aqueduct destination. This helped to reduce the chance of damage to the pipes from the force of the water. Perhaps the most famous example of an intact castellum aquae is at Pompeii, though other examples have been found, such as at Nemausus (modern Nîmes). Also sometimes called the castellum divisiorum.
