It’s a small dam, made of stone shaped in a “L” shape, although both sides appear to be equal in length. There’s a raceway that goes from the southern-most point towards Hebron Avenue before disappearing into the raised surface of the road.
The purpose of the dam is a mystery. It doesn’t appear on maps available on the internet. It appears to have been abandoned for a long, long time and was probably stood a few feet taller when it was built. The stream cuts deep into the ground which indicates that years of leaves and other decayed matter built up that high.
The sluiceway indicates that the water was collected and directed for a purpose but the new section of Hebron Avenue likely buried any ruins that could’ve offered other hints.