Our organizations recommend choosing Alternative 3 – the Full Removal of Springbank Dam and the naturalization of this section of the Thames River. We submit that full dam removal and naturalization are the preferred solutions from an environmental perspective and would likely prove to be the most cost-effective over the long-term when Life-cycle costs and available provincial and federal funding are considered.
The full Capital and Life Cycle Costs of Rebuilding Riverside Dam were not realistically represented in the ESR and could well end up costing the taxpayers more than double what was presented to the public and City Council. A Rebuilt dam would be considered a new dam, not a repair or expansion of an existing weir, with an assessed High Hazard Potential, and is located within the City of Cambridge in a location that could place multiple residences and businesses at risk in the event of severe flooding or a dam breach. ORA and Partners submit that this Project goes far beyond the screening process provided by a Schedule B, Class EA. Consequently, we submit that this is a major project that should fall into a higher level of assessment.
ORA understands the pressure municipalities are under when communities rally to maintain or rebuild their beloved mill ponds. However, it is up to all authorities and municipalities to take a leadership role that places public safety and landscape scale ecological integrity above local individual or group interests.
On 23 – 24 June of 2017, the upstream Gorrie Dam failed and the Howson Dam was at capacity during an extreme rain event and flood when 175 mm of rain fell in just 7 hours, placing more than 150 property owners at risk and resulting in an estimated $11-million in damages in the Town of Harriston. This severe rain event broke previous records by approximately 40% and was the second highest flow on the North Maitland in the 48 years of record. Fortunately, no one was killed; however, it could have been much worse, as in October of 2015, when a South Carolina flood breached 18 dams, and resulted in 16 deaths.
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.
Drought conditions could place additional stress on riverine ecosystems, while more extreme rainfall will heighten the risk of dam failures (18 dams were breached in a South Carolina flood in October of 2015) with rapid release of high volumes of water. There have also been recent dam failures right here in Ontario – the Gorrie Dam failure last year in Wingham was the most recent, putting more than 150 property owners at risk.
The goal of the Rotary Club Dam Removal Project was to remove a very old dam and headpond from Armstrong Creek, a tributary of the rocky Saugeen River, and to rehabilitate the stream bed to better support a strong population of wild brookies. Continue reading
Jeff Graham made this excellent presentation at the 17 June 2017 ORA General Meeting. He talked about his experience in southern Ontario with several dam removal projects – right from inception, through to decommissioning and river restoration. He gave some excellent tips that are well relayed in the presentation below:
Trout Unlimited Canada and the Ontario Rivers Alliance are requesting the County of Wellington Warden and Councillors consider supporting the decommissioning of the Hillsburgh Dam with an offline pond, which is the preferred alternative from a natural heritage perspective. This would provide positive environmental benefits to the West Credit River ecosystem, provide resilience to climate change, and support a multi-species ecosystem-based recovery initiative for the long-term. Including updates: Continue reading