Dams
It is dammed in two places - the best known is the upper river dam known as Mundaring Weir which was part of C.Y O'Connor's Goldfields Water Supply Scheme.
Since the lower dam - known as the Pipehead Dam has been constructed in the 1970s, flooding of the lower Helena River (in East Guildford and Guildford) has been substantially reduced. Most of the water collected in the Pipehead Dam is pumped back into Mundaring Weir. Due to this, restrictions in the Helena River catchment have been made to not allow activities that affect the quality of the Pipehad Dam - despite being adjacent to the built up areas within the Shire of Mundaring on the north side of the Helena River catchment.
Read more about this topic: Helena River