Hard to fool-proof climate adaptation when there are so damn many fools out there. See above.
Below, in the best of conditions, California’s ongoing Park fire would have been difficult to hedge against. Even those who went thru previous fires and took precautions were taken off guard.
Below that, Vermont’s River Flooding, dredging Rivers is not a clear solution.
The Park Fire demonstrates how years, if not decades, of weather patterns in a changing climate can converge to send flames raging through remote wilderness and mountain outposts at shocking speeds.
Historic drought left trees weakened or dead. Stormy winters washed debris into piles, while the rain allowed flammable grasses to thrive. Intense heat, smashing records across California this summer, dried everything out.
And then, there is the element of randomness in where fire moves after it ignites. Like most wildfires, Park was sparked by human activity. A witness saw a man push a burning car down a hill near a popular swimming hole in Chico’s Upper Bidwell Park, though the suspect told authorities it was an accident, according to local reports.
With winds flowing from the south, that meant flames fanned into some pristine and densely forested wilderness in Lassen National Forest, toward the southernmost peak of the Cascade range of volcanoes. The same treacherous terrain that made the area’s Ishi Wilderness a refuge for native Yahi people — a man named Ishi was the last of the tribe to remain there — allowed the fire to rapidly consume the rugged landscape.
Ecologists had hoped parts of the wilderness had experienced enough fire that they could weather the burn. One ponderosa forest studied for decades, known as Beaver Creek Pinery, was thought to be a prime example of a fire-tolerant and healthy forest, and scientists had been planning a prescribed burn in the area to see how it would fare.
But other parts of the forest had no known fire history in a century of recordkeeping. That made it much easier for the fire to spread and fueled extreme plumes that created towering infernos that firefighters could hardly battle.
“One might think, well, is there any area of California that hasn’t burned?” said Eric Knapp, a research ecologist for the U.S. Forest Service in Redding, Calif. “But there are still vast landscapes that have seen far too little fire.”
Last month, the town of Johnson got lucky. When the Lamoille River overflowed its banks for the third time in a year, the river didn’t reach the town’s wastewater plant. Only a few inches of water got into the new post office. Most homes and businesses were spared.
“We dodged the bullet,” said Erik Bailey, the town manager. “By the skin of our teeth, basically.”
Bailey says three recent floods — last summer, in December, and again this July, are among the top five biggest floods in Johnson on record. He has a theory about why so many of the worst floods have happened so recently.
“Everyone’s gonna say climate change, and I’m sure it might have something to do with it,” he said. “But the biggest thing, I’m fully convinced, is because the rivers are so shallow now, because we stopped dredging.”
This idea of digging our rivers deeper as a way to protect places like Johnson in some ways feels obvious.
“Intuitively, it makes all the sense in the world. If our buildings are getting wet, then let’s make the channels deeper, let’s make the pipe bigger, and transport that water downstream,” Shayne Jaquith, a river scientist with The Nature Conservancy, said on Vermont Edition last month.
“That’s what the early European settlers started doing, and that’s what we kept doing.”
Dredging prevents flood waters from rising as often. But it comes with a big tradeoff. When rivers do flood, they’re a lot more destructive.
“The channel just explodes, it just enlarges, really,” Jaquith said.
When you make a stream deeper, it becomes more powerful — sort of like a firehose. Eventually, that pressure will release. That’s when roads and bridges wash out, and homes get swept away. Not from rivers rising, but from the sheer force of water. That’s what happened in East Burke this week.
“It was just the pummeling — the pummeling that the bridge abutments are taking right now — that’s what’s causing the damage,” said town administrator Jim Sullivan, as he watched Dish Mill Brook pound into Mountain Road Tuesday morning.
This type of damage — from erosion — is so widespread because people have messed with some 75% of Vermont’s rivers over the last few hundred years, according to state assessments. Jaquith, with The Nature Conservancy, has looked into some of this history.
“Some of the images of the dredging that happened — it’s just mind boggling,” he said. “Like 15 feet of digging downward and it’s just like, how did they think those vertical banks are not just going to collapse,” he asked.
“Then, of course, there’s dynamiting the rivers to straighten them out.”
In recent decades, there’s been a big push to counteract this legacy of dredging by cutting into river banks and leaving space for rivers to spill outand release some of their energy — creating floodplains.
It’s well established floodplains slow down rivers and can prevent damage during storms: Having wetlands upstream of Middlebury saved the town up to $2 million in damage during Tropical Storm Irene, according to a University of Vermont study. More recently, a five-acre floodplain in Northfield reduced flood levels by six inches last year, according to the Friends of the Winooski River.
But in some areas, floodplains alone aren’t enough.
“Restored floodplains doesn’t change the fact that so many of our village centers are just built in floodplains, where it’s going to naturally flood, especially in light of a changing climate,” said Rob Evans, who runs the rivers program at the Vermont Department of Environmental Conservation.
We can’t dredge our way out of flood damage either — at a recent press conference, state officials said to replace historic floodplain capacity in Barre City, you would need to dig 100 feet down in the Stevens Branch.
UPDATE: Just because its cool
I always appreciate the flood pictures that show riverside areas with partially submerged concrete picnic tables and other durable features: Establishing parks on floodable greenspace give them both communal and practical value.