More With Less: Climate and Clean Energy Require Rethinking Rivers

November 28, 2022

Laurence Smith PhD in the New York Times:

Last month, record low water levels in the Mississippi River backed up nearly 3,000 barges — the equivalent of 210,000 container trucks — on America’s most important inland waterway. Despite frantic dredging, farmers could move only half the corn they’d shipped the same time last year. Deliveries of fuel, coal, industrial chemicals and building materials were similarly delayed throughout the nation’s heartland.

This critical river and its tributaries — responsible for transporting more than $17 billion worth of farm products and 60 percent of all U.S. corn and soybean exports annually — has been stricken by drought since September, amid a time of global grain shortage and soaring food prices. While water levels will recover modestly this week, thanks to some upstream rain and snow, the long-term forecast remains dry.

Conditions are even worse in the southwestern United States, where an ongoing 22-year drought — now the harshest in 1,200 years — has shriveled Colorado River reservoirs, straining water supplies for farms, cities and hydropower from the Hoover Dam. Across the Atlantic in Germany, warmer temperatures and longer droughts have shrunk the Rhine River, making navigation harrowing on a waterway responsible for up to 80 percent of the country’s ship-bound cargo.

Economic powerhouse rivers like these are being sucked dry not only by climate change but by fast-growing cities and farming operations that need more water. Agriculture is the single largest consumer of freshwater, and global food demand is still rising.

There are no new rivers left to tap. We must learn to do more with less.

Because rivers deposit sand, plugging shipping channels and reservoirs, their power to move sediment is normally framed as a problem to be fixed by dredging. But in Louisiana, where coastal wetlands are disappearing rapidly, a roughly $2.2 billion proposal is advancing to divert part of the Mississippi River into Barataria Bay, where additional sediment can help protect it from rising sea levels. Using BP settlement money from the 2010 Deepwater Horizon oil spill catastrophe, the Mid-Barataria Sediment Diversion would mimic natural delta-building processes in a place that has lost hundreds of square miles of coastal land over the last century. Projects like this one make the Mississippi’s ability to move sediment an asset rather than an expense.

If reservoirs fall to the point where they can barely be used for hydropower, they can still be used to store intermittent wind and solar energy — by recycling water that has already passed through the dam’s turbines back into its reservoir.

One outlandish proposal to do this at a massive scale reimagines the Hoover Dam as a three-billion-dollar renewable energy battery, connecting it to vast new solar and wind farms. While logistical issues make this particular idea a moonshot, there are plenty of opportunities to connect dams with renewable energy farms at a much smaller scale and lower cost.

Creative opportunities also exist for small, low-impact hydropower technologies — including modernized water wheels that can be retrofitted into existing or historical dam structures. Some technologies require no existing structures at all. Hydropower projects that are small enough to operate in reduced flows and small rivers can generate clean, renewable electricity with little environmental downside. Already some 200 low impact projects in the United States have been approved or are pending certifications, and across Europe there may be nearly 30,000 more potential sites at old mills.

Simply ripping out obsolete structures can have a big effect, too, restoring rivers to a free-flowing state with tremendous ecological and recreational benefits. Federal regulators have just approved an extraordinary plan to demolish four aging dams that for a century have been blocking salmon spawning runs on the Klamath River in California and Oregon, drawing protest from Native American tribes and fishermen. Rivers restore their old characteristics amazingly quickly once their shackles are removed. Based on studies of smaller dam demolitions on the Elwha River and others in the Pacific Northwest, salmon should begin recolonizing their ancestral waterway almost immediately.

Much more at the link


Bridge: (Michigan)

GLENNIE — Just west of this tiny town near Oscoda sits one of six hydroelectric dams that tamed the Au Sable River a century ago to supply power to a growing population.

At the time, before policy had caught up to the environmental consequences of dams, the impoundments seemed like miracle assets, delivering emissions-free power as reliably as a river flows. The ponds they created became destinations for boating, swimming and fishing, fueling tourism in a part of the state with limited jobs.

But fast forward a century, and the same structures have become expensive, environmentally costly assets that deliver negligible amounts of power at a premium price.

Their owner, Consumers Energy, has begun to ask whether their existence still makes sense.

All of which lead Tonya Wertheimer to wonder: If the Alcona Dam were to disappear tomorrow, taking with it the 1,075-acre reservoir that draws tourists all summer long, would Glennie’s grocery store be next?

“Where are we gonna buy our bread?” the 67-year-old resident said through tears at a recent public meeting hosted by Consumers. “Where are the people that actually live here, where is this community going to survive?

Consumers, one of Michigan’s largest electric utilities, began a lengthy process this autumn to consider the future of its 13 hydropower dams that plug five Michigan rivers: The Au Sable, Manistee, Muskegon, Grand and Kalamazoo.

At issue is whether to keep the impoundments in place, or remove them. The decision has more potential to alter Michigan’s rivers and the communities that surround them than perhaps any action since their construction stopped up the rivers and inundated a collective 17,200 surrounding acres with water that people built lives and livelihoods around.

While the company is years from making a decision, its deliberations are drawing keen interest from nearby residents who fear lost property values and dying towns, from electric ratepayer advocates wary of the high costs to maintain dams that deliver little power, and from environmentalists who see a once-in-a-lifetime chance to restore rivers harmed by the impoundments.

During hydropower’s heyday, Consumers and its predecessors owned more than 90 dams across the state. 

The structures generate electricity by stopping up rivers, flooding the land behind the dams and then releasing that water through the dam, where the force of its flow spins turbines to power a generator. 

For much of the last century, it was a cheap and reliable form of energy. But its massive environmental tradeoffs quickly became clear. The dams fragmented rivers and warmed their water, harming fish. Fluctuations to rivers’ flow from the fillup and drawdown of reservoirs interrupted natural rhythms that guide many river species’ reproduction and growth cycles. And sediments became trapped in reservoirs, starving the river downstream while causing the ponds to fill with silt.

“It’s not best for the river,” said Tess Nelkie, board secretary of fishing and river conservation group Anglers of the Au Sable. “And it’s not best for everything that lives in the river.”

Over time, the economics of power generation shifted, too. New regulations ended the practice of “peaking,” or filling and then rapidly draining reservoirs to maximize power output during times of high demand. As a result, the dams now operate at less than 40 percent of their capacity.

And cheaper energy sources entered the fray while the aging dams became increasingly expensive to operate and maintain.

Today, “it’s one of the more expensive power sources we provide,” said Adam Monroe, Consumers’ executive director of hydro operations. Wind, for example, is 31 times cheaper.

Amid those changes, Consumers sold or retired most of its dams between the 1940s and 1970s. The 13 that remain provide just 1.2 percent of the utility’s annual power mix, barely enough to cover their $12.6 million in annual operating costs. 

And at an average of 105 years old, Consumers says the dams need hundreds of millions of dollars in maintenance and upgrades to continue operating safely.

The company’s dilemma is familiar: More than 80 percent of Michigan’s 2,521 dams have aged beyond their intended life span, resulting in growing costs to keep them going. Hydropower’s waning cost-competitiveness at times leaves dam owners struggling to cover those costs.

Those imbalances played out dramatically in 2020, when two privately-owned Midland area dams failed amid heavy rainfall. Regulators for years had flagged safety issues at the dams, but Boyce Hydro insisted it lacked the money to make fixes.

Following the disaster, a state task force concluded that dams across the state need “immediate attention” to avoid future tragedies, including money to fix problem dams and “substantially enhance dam removal.”

Federal regulators consider Consumers’ dams to be in satisfactory condition, with none of the alarming deficiencies that plagued the Midland dams. But licenses for 11 of the 13 dams will expire in 2034, putting the company on a timeline to decide whether it’s logical to make the investments needed to keep them safe for the future. 

Consumers is considering one of four options for each dam: Relicense and continue generating power; sell to a new owner who would maintain the impoundment; remove the dam and restore a free-flowing river; or build a new barrier that generates no power, but preserves a reservoir.

Consumers plans to announce its preferred solution for each of the 13 dams next year. After that, state and federal regulators will decide whether the company can move forward with its plans. 

The idea of losing the dams has nearby residents nervous. 

On the Kalamazoo River, hundreds of residents who live on the reservoir created by the Calkins Bridge Dam have joined a property owners’ association that is lobbying for its survival. On the Au Sable, a Facebook group has cropped up devoted to saving the dams. 

And across the state, large crowds showed up at public meetings with Consumers to voice their fears about the future.

“All of these communities are dependent on waterways that are created out of those dams,” said Coco Soodek, president of the Lake Allegan Association, which represents landowners on the impoundment created by the Calkins Bridge Dam, near Allegan in the Kalamazoo River. “And the communities that surround those bodies of water would be destroyed.”


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