From KUNC (Jackie Fortier):
As the evening wore on, people living in two trailer parks just south of campus began to panic. Located in a low gully near Spring Creek, between College Avenue and a 15-foot railroad embankment, the trailers had begun to fill with water.
“The rain kept falling hard on the same areas that had just had the heaviest rain so it was building this flood surge,” said state climatologist Nolan Doesken…
Over the course of 24 hours, 14 inches of rain fell in southwest Fort Collins in a highly-localized storm.
“And if anything that was what set the 1997 storm apart, everything was already soaked before it started — I mean really soaked — and then it dumped five hours of heavy rain, with the last hour being the heaviest of all,” said Doesken.
Most of the water was building up behind the 15-foot railroad embankment near Spring Creek — where the trailer parks were.
“Spring Creek is tiny. When you look at it, you can almost jump over it most times of the year,” said Marsha Hilmes-Robinson, floodplain administrator for the city of Fort Collins.
During the flood, the railroad embankment was holding back 8,250 cubic feet of water per second.
“Think of each cubic foot per second being one basketball going by a location in one second,” Hilmes-Robinson said. “So we had 8,250 basketballs flowing into the area behind the railroad embankment every second. That’s a lot of water.”
The railroad embankment couldn’t hold. One of the culverts that had intentionally been filled blew out and water pounded through and eventually over the top. As the rain continued to pour through the night, residents of the trailer parks clung to trees and huddled on rooftops before rescuers in rubber rafts could reach them.
“Then there was the fires, because some of the trailers had floated and the gas lines had been ruptured there was another explosion at a liquor store just to the north of the mobile home park, and then the train cars derailed,” Hilmes-Robinson said.
Four train cars full of lumber and grain had been knocked off the tracks at the top of the embankment as the water began to go over the top.
Rescuers worked through the night saving hundreds of people. Meanwhile at Colorado State University, 40 buildings were flooded, sustaining damages over $100 million, including to the newly renovated Morgan Library and the Lory Student Center.
In all, five women died in the Spring Creek Flood and 200 homes were destroyed, including both trailer parks. Damages to the city and campus totaled $200 million.
Since the Spring Creek Flood, an extensive rain gauge network has been installed in the foothills and in the city as an early warning system. The city has also taken an integrated approach to new projects, according to deputy director of the Colorado Resiliency and Recovery Office Iain Hyde.
“When a new bridge or culvert or park is built, [Fort Collins] build risk reduction into that process, really thinking about floodplain management and sound regulations, and those actions are reducing risk but they’re also reducing risk for flood insurance for members of the community as well,” Hyde said.
Now a gleaming apartment complex and strip malls sit where the trailer parks were. But the new construction had to meet need code regulations put in place after 1997, says Marsha Hilmes-Robinson.
“Those city codes required the buildings to be raised by 18 inches above the 100-year floodplain,” she said.
Flood mitigation also means giving the water somewhere to go. Fort Collins has used sales taxes to purchase two-thirds of the land in the 100-year Poudre River floodplain within city limits, turning it into natural areas and parks. The idea is to give the water somewhere to spread out and slow down. So far, it seems to be working.