SAN DIEGO — Last week's storm has been called a “thousand-year storm event” by San Diego city leaders, causing major flooding all over San Diego. With another storm in the forecast this week, city crews have been clearing tons of debris and vegetation from the Chollas Creek flood channel.
“Basically after every storm they come to clean. They should’ve cleaned before the storm, not after the storm but they always do after,” said Claud Wei, who manages an apartment complex that backs up to the channel.
Nearly four inches of rain fell in the span of just a few hours.
“If you drop four inches over the whole city and you start collecting that into certain spots, you’re going to run into problems no matter what because it falls so fast that it can’t leave in a gradual way,” said Bruce MacVicar, Associate Professor in the Department of Civil and Environmental Engineering at the University of Waterloo. He teaches classes on the design of urban stormwater systems.
“Suddenly the earth itself is moving, so the channels get choked up full of debris and sediment, and the capacity of the openings suddenly reduces drastically so there’s nowhere for the water to go,” said MacVicar.
He told CBS 8 neighborhoods developed prior to the 1970’s and 1980’s like Southcrest and Mountain View typically weren’t given much consideration for big rain events when they were built.
“In older systems, the water just starts to have to find its way through neighborhoods and so then that obviously becomes a problem for anyone that lives in the pathway of where that water’s going to travel,” said MacVicar.
When looking at the layout around Chollas Creek, MacVicar told CBS 8 he thought Southcrest has a number of disadvantages in terms of planning, which he said were typical of older neighborhoods.
“Highway was built across the river, highway 5 kind of comes across, right, they put a clover leaf to get off the freeway in what probably was the floodplain,” said MacVicar. “That could be a choke point where the water is trying to get through a very small area and in these big events where suddenly there’s so much water trying to get through, it just can’t and upstream just becomes a bathtub.”
Meanwhile, Weis is optimistic the work being done to clear the storm channel in his neighborhood will help to keep it from flooding again when it rains later this week.
“Once trees are cut and also after the first rain washed down the stuff, the next rain usually isn’t as bad,” said Wei. “I watched for five years all the rainstorms, I understand the pattern now.”
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