Aqueducts and mystery beige animals

During our visit to the aqueducts I was personally impressed by the precision of engineering of the waterways. To have them slope exactly enough to transfer water over such a long distance required a great deal of measurement. I didn't previously know that it was common to have two different duct systems run atop each other. This allowed for a much great total flow rate of water. Having the opportunity to feel the water that would have been transferred, it was surprising how cold the water could stay over such a long distance.