how worsening wildfires fuel a discouraging trend for more flooding - materials that absorb water

by:Demi     2019-08-22
how worsening wildfires fuel a discouraging trend for more flooding  -  materials that absorb water
Wild fires have destroyed the natural system in which our forests absorb rain and snow, causing flooding. C.
The fire season is getting worse.
The trees on the forest floor and the absorption of organic matter are not only burned by a strong forest fire, but the burning materials and Ashes will also cause the water to bead on the surface and accelerate into the swollen stream, university B said. C. forestry Prof. Lori Daniels.
The trend line is far from encouraging.
In the summer of 2017, driven by a high-altitude fire west of kuisnell, the burning area reached 12,000 square kilometers, setting the largest wildfire record in the province's history.
In fact, in the four worst fire seasons of B. C.
History has come in the past eight years.
For people living near the biggest fire area of last year, this is bad news and bad news for areas like Okanagan and Similkameen.
"We have noticed that the fires are affecting the floods and they happen together," Daniels said . ".
"We see this pattern in B. C.
After the Boulder Creek fire in 2015, rainfall in November caused flooding in Pemberton Meadows and downstream areas of the liowett River. Cache Creek —
Where the state of emergency is declared-
It was the base of 1,920 last summer-sq. -
Xiangshan fire area kilometers.
A healthy, mature forest manages rain and snow in many ways.
The snow on the branches may evaporate directly back into the atmosphere, and the green canopy will catch up with the spring rain before reaching the ground, Daniels said.
The thick organic matter on the forest floor is like a sponge, which greatly reduces the amount of water flowing to the stream when the snow melts.
"These organic materials can absorb a lot of water," she said . ".
"Then it will enter the mineral soil and possibly reach the ground water. ”A post-
Wild Forest is a completely different place.
Not only are the trees destroyed, but a thick layer of organic absorption may also be burned, depending on the intensity of the fire.
If this is not bad enough, the burnt forest duff is rich in fat and wax, which form a smooth surface for water beads, pools and loss.
"The wax-containing films make the soil water-repellent, so they no longer absorb water and they fall off," she said . ".
"After a fire with white ash, you can see the ditch forming a small passage instead of soaking in it.
When the flow of water leaves, it will flood the stream quickly and drown our river.
The speed and volume of the water can also lead to erosion, scouring the banks of the river, releasing a large amount of debris, resulting in blockage and blockage of the drainage system.
The risk of landslides and mudslides is also increasing in combustion.
It is reported, especially after heavy rainfall.
In general, the severity of flooding depends mainly on the combination of snow and warm temperatures and precipitation, says Brett Gilley of the Faculty of Earth, Ocean and Atmospheric Sciences at ubc. Recent summer-
It's like the temperature caused the flood, but it's still a few weeks away from the peak of the flood season.
The rain in the snow may also accelerate the melting and increase the volume of runningoff.
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