Nature Wise: Dams are more complicated than they look

Once upon a time I designed and built a 28- foot Peace River shoreline diorama for a Site C dam information exhibit

Dianne Bersea is a member of the South Okanagan Naturalists Club.

Once upon a time I designed and built a 28- foot Peace River shoreline diorama for a Site C dam information exhibit.

Yes, this dam has been on the books for years, since the ‘60s at least. My contribution supported the dam during the B.C. Utilities Commission hearings of 1981-83. Site C failed the review, apparently because B.C. Hydro didn’t take energy prices into account or provide “statistically significant” evidence that it was needed, my exhibit efforts notwithstanding.

Read more: Kelowna coalition formed to oppose Site C

In April 2009, in company with a friend from Fort St. John, I sat on the high banks of the Peace River just a little bit west of the proposed dam site. Below us, ice and snow were still melting from the river islets and I could hear the early arriving Canada Geese honking a spring hello. Sandy spread her arms and embraced the river and all about us. “I absolutely love this,” she enthused. At the time, the prospect of a dam seemed unlikely and far away.

Then things changed. As of 2010 someone wangled an exemption from further Utilities Commission reviews. Now, in 2016, the B.C. government is forging ahead with damming up the Peace River. Unless some miraculous intervention occurs the Peace River will be burdened with three dams. Two dams already exist.

Back in the ‘50s, a family road trip introduced me, an ever-curious eight year old, to the Grand Coulee Dam, a startling concrete behemoth. From that day forward I saw dams as the engineering marvels they are, holding back trillions of tons of water to irrigate vast tracks of water-starved land and generate electricity to power our exciting  modern lives.

In the ‘70s I learned that interfering with a river can have unfortunate consequences. A proposed project to divert the waters of the Kootenay River into the Columbia River severely shook the Kaslo community, my lakeshore home. The diversion was said to seriously threaten Kootenay Lake, perhaps dropping the lake level as much as 50 feet. Such a drop would decimate lakeside communities. Marinas would close, ferry terminals need rebuilding, real estate values tumble, and renowned Kokanee salmon disappear, all for power to the big cities.

Happily that project didn’t go ahead but it gave me a new dam perspective. Anything that happens anywhere within the complex network of a drainage basin has a significant impact both upstream and downstream.

Some of those impacts are large scale; drowned valleys and ecosystems, drowned communities and agricultural land, farmland we can’t afford to lose. The less obvious impacts block fish migration routes and decrease flow rates above and below dams.

I’ve learned that slower moving water is warmer and contains less oxygen than faster moving water. Decomposing vegetation and tree debris on the reservoir floor also consume oxygen, especially in summer. Most aquatic life depends on higher rates of oxygen and many are adapted to rapid, cooler water flows.

Behind the dam, water that has been stilled will increase silt deposits affecting habitat as well as presenting a danger to the dam itself. There can be changes of a chemical nature, the most disturbing of which is the bacterial transformation of decomposing matter from harmless inorganic mercury into methyl mercury, a neurotoxin that moves up through the food chain. Think on that for a moment.

For a powerful look at the impact of dams take a careening ride, courtesy of Kevin Fedarko’s book, The Emerald Mile, through the Grand Canyon on the Colorado River, one of the most heavily dammed rivers on the planet.

What is required to care for our rivers in B.C.?

Can we allow them to flow more freely?

Or, allow important rivers to remain dam free?

Are some dams past their best before date?

Can we find more effective, less damaging ways to power up?

Dam right! Dams are worth a more thorough look before we dam up the Peace River one more time.

Dianne Bersea is a member of the South Okanagan Naturalists Club (SONC). The opinions expressed here are those of the writer and do not necessarily reflect SONC — southokanagannature.com.

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