From the Introduction: A small but steep valley cut into the ground by the small river currently flowing peacefully at its bottom divides the land. While a dirt road runs along the rivers length using the valley as a natural traffic route the fresh water for a nearby town has to be moved across the valley. Resourceful builders bridged the valley with a small two tier aqueduct. This way the water can flow across the valley without problems and neither the traffic on the road or the water in the small stream are staunched in the least. As a bonus travelers wanting to cross the valley can now do so without having to climb to its bottom and getting their feet wet.