Category Archives: Gorrie Dam

Howson Dam Removal Project – North Maitland River

  • Howson Dam - North Maitland River, Wingham, Ontario.

The Howson Dam Removal Project on the North Maitland River began in July of this year and is expected to be completed sometime this Fall.  ORA advocated strongly for the removal of the Howson Dam instead of repairing or reconstructing the dam that was so clearly having negative effects on water quality both upstream and downstream of the dam.  Stay tuned for more pics as the Project progresses.  Removal of the Howson Dam reconnects approximately 100 km of uninterrupted Chinook Salmon and Rainbow Trout habitat on the Maitland River system, from Wroxeter all the way to its outlet at Lake Huron in Goderich.

Check out ORA’s role in getting this done – click here and scroll down.

On 23 and 24 June 2017, during an extreme rain event, the Gorrie Dam washed out, and the Howson Dam was at capacity when all the stop logs could not be removed.  Both dams failed when 175 mm of rain fell over a 7-hour period, placing more than 150 property owners at risk.  This severe rain event and flood resulted in an estimated $11 million in damages in the Town of Harriston and broke previous records by approximately 40%.  It was the second-highest flow on the North Maitland in the 48 years of record.

All remnants of the Gorrie Dam were removed, and the river was reconstructed in 2021.  Another ORA advocacy success!



Update: Gorrie Dam on the North Maitland River to be Decommissioned

UPDATE:  Gorrie Dam Demolition Underway, Toronto Star, 23 July 2021

The Gorrie Dam failed as the result of an extreme rain and flood event in June of 2017.  The dam had failed before, so the ORA advocated for its decommissioning, rather than its repair.

Part of the earthen berm to the south of the dam failed in June 2017. In June 2019, after reviewing a study of alternatives for the dam, the Conservation Authority membership decided to begin the process of decommissioning the structure which is located at Gorrie Conservation Area.

It is crucial that we take action on infrastructure that would put citizens at risk, degrade water quality, threaten our fisheries, or that jeopardize the ecosystem services that healthy rivers provide.

The Maitland Valley Conservation Authority has decided to decommission the dam and will move ahead with decommissioning in 2021.

Maitland Conservation Moves Ahead With Next Steps at Gorrie Conservation Area, 6 July 2020, by Maitland CA.


Gorrie Dam Failure, North Maitland River

Gorrie Dam Breach – Scour Hole

It has come to ORA’s attention that the Gorrie Dam on the North Maitland River failed as a result of flooding during an extreme rain event on 23 – 24 June 2017, and that Maitland Conservation is considering its options.  We understand that no one is more aware of the extremes of a volatile and changing climate than Conservation Authorities, and yours in particular; and we understand the pressure that Conservation Authorities and municipalities are under when communities rally to maintain their coveted mill ponds.  However, it is up to all authorities to take a leadership role that places public safety and landscape scale ecological integrity above local individual or group interests.

Continue reading