After terrorizing neighborhoods from Coatesville to Downingtown, the Brandywine flood waters reached a crescendo in Chadds Ford. By that time they were two stories high and were going wild at an incredible 33,000 cubic feet per second, a ferocity beyond anything in the record period.
Waters crashed into the Brandywine River Museum – home to some of the area’s most significant works of art, including paintings by Andrew Wyeth that captured the tranquil and mystical sides of the valley – filling the lower level up to the ceiling and damaging the 10 buildings in the complex.
Ten weeks after the historic flooding caused by the remains of Ida, and with the peak holiday season now looming, the museum remains closed and it’s unclear when it will reopen.
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While no one was injured and all of Wyeth’s paintings and other artwork spared, the museum complex suffered at least $ 6 million in structural and property damage, said Virginia A. Logan, executive director of Brandywine Conservancy & Museum of Art.
“We’ve never seen anything like it,” she said.
No one else did either, according to a hydraulic analysis of Brandywine at Chadds Ford conducted last week by Gerald Kauffman Jr., director of the Water Resources Center at the University of Delaware. The US Geological Survey ânever anticipated this extreme flooding,â nor any other government agency, he said.
A two-story flood wave – three times the depth of the creek at Chadds Ford – submerged the banks of the creek, and all Ida-related record peaks verified by the National Weather Service, this one was n Â° 1 in terms of surpassing the previous record.
What was captured on the USGS gauge fair at the museum was a dramatic encapsulation of the unprecedented ferocity and nature of the Ida-related flooding. Conspirators identified by experts included typography, increased rains associated with climate change, a single downpour every 1,000 years 18 miles upstream, a cascade of water 1,000 feet above sea level, and a fateful 19th century engineering decision.
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It probably wasn’t what Andrew Wyeth had in mind when he said, “I don’t think there is anything really magical unless it has some terrifying quality.”
The Brandywine watershed covers 38% of Chester County and all or part of 41 towns, according to the Stroud Water Research Center Environmental Review Report. Shaped like a tuning fork, the western and eastern branches of Brandywine Creek in western Chester County join the main stem near Lenape, and it becomes seriously pinched as Chadds Ford approaches.
The shores of the museum site are about 80 feet apart, less than half of the separation a few hundred yards upstream, says Kauffman.
The watershed’s population has increased by 10% during this century, and with it paving and other hard surfaces have increased, according to his analysis. Between 1996 and 2010, the watershed added nine square miles of developed land, or about 300 football fields.
Perhaps surprisingly given that the Brandywine crosses both the Route 30 and Route 1 corridors, just under 6% of the watershed is covered in hard material, according to the Kauffman report. This is because a large part of the area is “protected”.
The development has contributed to Ida’s havoc, said Seung Ah Byun, executive director of the Chester County Water Resources Authority.
Nonetheless, Stroud Center director Charles Dow believes Ida’s rains likely outweighed everything else. When rain overwhelms even a meadow, he said, it can take on the character of a paved surface as more rain flows from it.
And while the overall amounts of rain in Chester County were staggering, the speed at which they came was abysmal.
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In Modena, on the West Branch of Brandywine, 7.02 inches out of a total of 8.18 fell during a six-hour period ending at 8 p.m. on September 1 – a downpour that would only be expected times every 1,000 years – according to a Chester County Water Resources Authority. analysis.
âMy grandmother used to say, ‘It’s raining cats and dogs,’â Kauffman said. âThis is higher than that. “
Six hours later, the aftermath reverberated on Chadds Ford, 18 miles downstream.
The museum has a permanent disadvantage in its battle with nature, Dow said: “It was built in a floodplain.”
Occupying a building that housed a mill dating from 1859, it opened in 1971. A year later it suffered what was then a record flood of Agnes’ remains, a record broken during Floyd’s visit to France. 1999 and Chadds Ford’s gauge reached 17.15 feet. Ida, at 21.04, was 20% higher.
The museum is still keeping track of the damage, Logan said. She added that neither insurance nor disaster assistance will cover the costs. The Brandywine Conservancy has set up a relief fund.
Kauffman says the museum’s flooding issues have a lot to do with human activity, and not just with increasing greenhouse gases or development.
At some point in the 19th century, it was decided to “channel” the banks of the Brandywine from Route 1, near the current museum site, several hundred meters east to make way for a road bridge. iron, he said. The narrowing of the banks provided a ground for the planting of the trestle supports.
âI think that’s the choke point,â he said.
Kauffman is convinced this can be fixed with the federal money on the table. He is part of a bi-state intergovernmental task force that is examining the basin and what can be done to mitigate flood risks.
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“This group, I hope, will move quickly, so that the unease doesn’t set in, and we’re not ready for the next big one,” he said. âWe are trying to avoid this.
“We call it the hyro-illogical cycle,” he said, “not the hydrologic cycle.”