Scale model of Springbank dam tests flood diversion impacts, raises critics' ire
by Bill KaufmannWhile final approval of the Springbank dry dam has been held up by regulatory hurdles, a model has been quietly built, far from prying eyes.
It’s a 1/16-scale version of the project — complete with identical and functional sluices, spillways, crest gates and even the woody flotsam it’s expected to catch during flooding.
Water has been forced through the model at velocities calculated to simulate a potentially disastrous flood.
The 50-metre by 30-metre model of the $432-million dam and reservoir was built by National Research Council of Canada employees in one of the agency’s cavernous Ottawa facilities.
Those behind the reproduction — which cost $800,000 to build and use — say it was crucial in helping to understand how the dam would function during a high-water event that would let loose many tonnes of debris along the Elbow River.
But opponents of the full-sized project — meant to prevent a repeat of the 2013 flooding that submerged parts of Calgary — say building the model’s a pricey slap-in-the-face.
“They continue to spend so much money to push this project while it’s still held up,” said Karin Hunter, president of the Springbank Community Association.
She said the mere existence of the huge model doesn’t inspire confidence among residents who live near the proposed site 15 kilometres west of Calgary along Highways 8 and 22.
“It shows how unsure they are about how it would run, the uncertainty of it,” said Hunter.
Federal environmental regulators have repeatedly sought more information on the project, prompting the province to send them an 8,000-page document last spring.
In an emailed statement, a spokeswoman with Alberta Transportation said the dam reproduction was commissioned by the previous NDP government in 2016 and was mandated by Ottawa.
“Detailed modellings on items such as water pressure and sediment deposit are required as part of the regulatory review process, and using a lab environment allows the best opportunity to create/re-create actual conditions,” wrote Brooklyn Elhard.
Provincial officials say tests using the model have led to several modifications to the dam’s diversion inlet and river gates that include improving the structure’s hydraulics.
Officials with engineering firm Stantec, which is also involved in the full-scale project, ran tests on the wood, metal, gravel and concrete model which was dismantled in November 2016.
Hunter said those likely to be impacted by the dam would like to know any results from the model and to have seen it in action themselves.
“The build up of debris has been a concern all along; why hasn’t anyone talked to us about this?” she said.
However, it’s simply good due diligence to construct such a model and its cost is likely well worth it, said Brenda Leeds Binder of the Calgary Rivers Communities Action Group, which supports the project.
“It sounds entirely prudent considering they’re building something they haven’t built before in Alberta, to my knowledge,” she said.
Some local landowners, Rocky View County, some MLAs and leaders of the nearby Tsuut’ina First Nation have expressed opposition to the proposed site of the dam and have argued a better alternative could be built upstream of Bragg Creek at McLean Creek.
Proponents say considerable research has ruled out McLean Creek as environmentally — and financially — viable while Calgary Mayor Naheed Nenshi has called the Springbank project crucial in protecting the city, adding the project’s further delay is unacceptable.
It would store water in an amount equivalent to 28,000 Olympic-sized pools, releasing it back into the Bow River after the end of a flooding event.
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