FEAR OFFLOODING
It couldn’t be happening in a worse place. The Pacific Northwest is
already universally known for its rainy climate, and global warming
will make winter rainfall heavier and more frequent. As mountain
snow is pounded with heavy rain, it melts and unleashes torrents of
water down mountainsides, into creeks, into rivers, and increasingly
into homes built on floodplains.
Already, Scott Weston sees signs of flooding trouble ahead.
Weston, a young geoscientist at Madrone Environmental Services in
Abbotsford, British Columbia, points to a series of photos. They show
what happened when—to the surprise of neighboring residents—
heavy rains caused the Lower Englishman River on eastern Vancouver
Island to come alive on March 13, 2003. It rose 2 meters in just 24
hours. “Turns out that this is a trailer park on the flood plain,” Weston
says, pointing to what looks like a river with buildings in it.
Floodwaters rose so high that water touched the bottom of an out-
door community bulletin board. Weston moves on to the next photo.
Here, the water turns a rural subdivision’s sole street into a virtual
river. It stands high enough to reach a parked car’s windshield. So
much water roared downriver that day that the Lower Englishman
River, which normally discharges 350 cubic feet of water per second,
suddenly sent 11,000 cubic feet of water per second careening down-
river. To put that into perspective, for several hours enough water
roared downstream every second to nearly equal the amount used in
an entire year by a typical American household (12,000 to 16,000
cubic feet).
With climate change, Weston predicts more frequent, bigger
floods of the Lower Englishman River, just as other scientists predict
more floods elsewhere. By 2020, the peak amount of water discharged
by the Lower Englishman River could increase by 8 percent a year on
average, according to computer models. By 2080, that average would
rise to 17 percent.
The likely conclusion: Flooding will reach people’s homes more
often. Government officials and developers make calculated gambles
when they allow development, projecting how often a certain-sized
Pacific Northwest 149