> The article mentions there were frequent wells and encampments
They aren't arguing that wells were dug to support the wall garrison. They're arguing that, because the wall needed to be garrisoned, it could only visit places where there were or could be wells:
>> our spatial and ecological analysis demonstrates that the distribution of local resources, such as water and wood, was critical in determining the route of the wall and the placement of associated garrisons and forts.
They aren't arguing that wells were dug to support the wall garrison. They're arguing that, because the wall needed to be garrisoned, it could only visit places where there were or could be wells:
>> our spatial and ecological analysis demonstrates that the distribution of local resources, such as water and wood, was critical in determining the route of the wall and the placement of associated garrisons and forts.
( https://www.mdpi.com/2073-445X/14/5/1087 )