Fires burning brush and forests are natural occurrences. There are even certain trees whose seeds only germinate after a fire. At some point we got it in our heads that all forest fires are bad and we should extinguish every one with extreme prejudice. (I’m looking at you Smokey the Bear.)
After some decades we learned the hard way that this tactic is wildly flawed. Fires require 3 things, oxygen, fuel, and heat. When you never allow ANY fire to burn even in a controlled manner you allow that fuel to build up, and build up, and build up.
What we learned by putting out every single fire is that you are exchanging frequent small fires for infrequent massive, completely uncontrolled, and devastating fires.
There’s nothing to be gained by flooding land, it will not prevent future floods or reduce the size or strength of them.
There’s nothing to be gained by flooding land, it will not prevent future floods or reduce the size or veracity of them.
This is not entirely true, though the purpose is not the same as controlled burns. We intentionally (re)flood wetlands we’ve previously dried in order to restore wetland habitats.
Kind of like the fires, though, we learned the hard way that draining all the wetlands is bad, and they’re actually very important features of nature.
In the context of controlled burns, there’s nothing to gain from flooding land temporarily in a similar fashion. However, rebuilding wetlands is actually a great way to prevent floods in other areas.
There’s nothing to be gained by flooding land, it will not prevent future floods or reduce the size or strength of them.
This is incorrect. Controlled flooding is used to mitigate the risk and effect of floods. This is especially common in the Netherlands, where designated areas - “uiterwaarden” - are periodically flooded as needed. These areas are typically used as pasture or for recreation under normal conditions.
Well said.
There’s a researcher who in the 80’s tried to tell the forest service all this, and they simply wouldn’t listen.
There’s even a news clip of him from the time.
I’ll see if I can find it.
Controlled flooding gives a place for the water to go when there’s too much. For example I remember reading about dikes along the Mississippi for flood control, but when there was too much water it would flood less inhabited farmland before city areas
Wouldn’t a dam be a form of “controlled flooding”?
I’ve actually done controlled burns in Northern BC back when I was in forestry. We go in during the winter and burn up dead branches that have fallen during the year. The snow stops the fire from spreading and the burning depletes the excess fuel on the ground, making it harder for fires to grow out of control in the summer. The burning also releases nutrients into the soil and encourages a healthy undergrowth by making space for new plants.
As others have mentioned there are also some trees(usually pine) that require fire to spread seeds. Those controlled burns are usually reserved for public parks where they want the forests to have a more natural look. They are small fires created with drip torches, just enough for the cones to open before being put out. When mass producing those pines trees to replant a logged forest, we use ovens to open the cones instead.
Controlled flooding is also very much a thing we do as humans either to divert water from flooding other areas, or to rehabilitate soil. Its pretty common throughout the world. I would bet that you are unfamiliar with the practice because you live somewhere beavers are already doing it for free.
Roofuskit hid the main answer to your question (within a great commentary on US wildfire): Fires require 3 things, oxygen, fuel, and heat.
Remove the fuel source in front of a fire, and you prevent its spread.
In the western US, this is done to create a fire break - a line which a wildfire can’t cross because there’s no fuel.
And the rest of what roofus said is very important: US policy around fires for the last 80 years or so has been to suppress ANY fire. This has had the opposite effect of enabling more undergrowth to form, meaning more fuel.
Additionally, California in particular essentially stopped all logging. Logging companies maintained what we commonly call fire roads - those roads were often an unintentional fire break. Those roads overgrew with the kind of growth (low scrub) that is ideal wildfire growth fuel.
Wildire in the western US is a lesson in assuming we understand how natural systems work, and have the ability to control them.
Edit: firefighters in a city/town remove oxygen when using fire suppressant materials. Water is used to remove heat when the fire turns it to steam.
CO2 is largely what’s in most consumer fire bottles - it provides an oxygen-free “cloud” to break the cycle of a fire by replacing the available oxygen.
We have that, it’s called “wetland restoration” and “don’t live in places that are natural wetlands”. Many cities with rivers are specifically designating areas that can expect to be flooded, to prevent the floods from spilling into areas with buildings.
When a dyke becomes too soaked it might collapse, they will open particular points to take pressure down. I’m not an expert by any means, but that’s my understanding.
Do you mean controlled flooding to prevent natural floods like controlled burns prevent natural fires?
We don’t have the water resources to fight fires with controlled flooding, or energy resources - flooding would come with its own ecological problems, affecting everything from plant life to animal to microbial, it would be an environmental disaster even if we had the resources and technology. Controlled burning is also good for nature, nature evolved for occasional burns, it feeds microbial life, it reboots life, it is necessary for many plants to even reseed. It’s cheap. It’s safe when done properly. It’s efficient compared to water. There are many more reasons, but these are the major ones.
Look to nearby colleges or universities with an agricultural arm. Example, https://snr.unl.edu/academicprograms/prescribed/index.aspx
Why not controlled flooding? Controlled fires are consuming a backlog of available fuel to mitigate the chances of a future uncontrolled fire. A flood wouldn’t be relieving any sort of equivalent pressures, they’re not analogous.
The Sutter Bypass and Yolo Bypass in California are examples of prescribed/controlled flooding infrastructure. When the Sacramento River is about to overflow its banks, the bulk of the flow spreads out into the bypasses, keeping the river level low and flooding agricultural areas rather than urban areas.
When I was a kid, one of the fields at the local park where we used to play football and soccer was lower than the rest and separated by berms. It was designed as a controlled place for water to go when the river flooded every spring with snow melt.
Of course, climate change means we now have a more permanent solution to snow melt
