More details requested for review of proposed Springbank dry dam
The federal environmental review of the proposed Springbank off-site reservoir wants more information from the provincial government, including additional details on what would happen in a worst-case scenario accident or malfunction.
Opponents of the dry dam proposal are raising their own safety concerns about the project, but the province says the federal request is routine and won’t affect the timeline for Springbank, which has already been delayed by 10 months.
The Canadian Environmental Assessment Agency sent the request to the provincial Transportation department on June 29, citing gaps in the information provided in the province’s environmental impact statement (EIS) from three months earlier.
The letter from Jennifer Howe, the CEAA’s prairie and northern region project manager, said there are 16 items that need to be addressed, raising specific questions in areas such as surface water quality, migratory birds and species at risk and human health risk assessment.
The federal agency also said the province “does not describe in sufficient detail the potential environmental effects of accidents and malfunctions for worst case scenarios such as off-stream dam failure or breach, and diversion structure failure or breach.”
“Although the proponent’s response includes a description of the potential worst case scenario for both a hazardous material spill and a pipeline rupture, the details such as location, volume, and type of material spilled are lacking,” adds the CEAA letter.
The agency wants more details on those areas and also wants the province to describe its contingency response plan for potential hazardous material spills. It also requested an updated assessment of the potential impact on groundwater from such a spill.
In statements provided by John Archer, press secretary to Transportation Minister Brian Mason, the Alberta government said requests for further information — including worst-case scenarios — are a normal part of the regulatory process and have been built in to Springbank’s timelines. Mason announced in May the project had been pushed back 10 months, with a completion date now slated for late 2022.
The Transportation department said it’s reviewing the federal questions and is preparing a response, reiterating the government remains committed to Springbank as the best option for flood mitigation.
“More than 600 individuals, including engineers, experts and designers, have worked on the project. We have also engaged a top environmental consulting firm to review the submissions to CEAA and established an expert technical team that is positioned to rapidly respond to any further questions from the regulators,” the department said.
The Springbank dry dam to prevent flooding on the Elbow River was launched following the 2013 deluge that devastated Calgary.
Located 15 kilometres west of Calgary, the $432 million project calls for the construction of a storage reservoir and a 4.5-kilometre diversion canal. Under the plan, the area remains dry at almost all times but in case of flood, the canal can be used to divert water into the reservoir, where up to 70.2 million cubic metres can be stored and then gradually released when the flood subsides.
While Springbank received approval from successive Progressive Conservative and NDP governments and is strongly backed by the City of Calgary, it faces fierce opposition from a group of rural landowners who will be displaced by the project, as well as from the Tsuut’ina Nation.
On the CEAA website, there are 672 public comments on the environmental assessment process around Springbank.
Among them is a report from Colorado geotechnical and water resources firm RJH Consultants, commissioned to conduct an engineering review of Springbank by lawyers for affected landowners opposed to the dam.
The firm’s Robert Huzjak said the province has not provided adequate information to judge the feasibility and safety of the Springbank project.
He also wrote that there are potential design flaws in the project related to the auxiliary spillway, diversion channel, emergency spillway and outlet gate that could lead to obstruction or potential failure of the dam.
The RJH report, submitted by MLT Aikins, also suggests that seepage in a typical dam section of the primary embankment could lead to a progressive erosion failure of the foundation and dam.
“If this scenario were to develop, significant loss of life ( greater than 100 persons) and significant property damage would likely result,” wrote Huzjak.
The Alberta government said it could not comment on the RJH report as it had not been submitted to the province.
However, while its focus is on responding to the CEAA, the province said it is working with its consultants to review all the documents filed with the federal government.