On Monday the 5th of October, South Carolina was hit with a deluge that occurs on average once per millennia, receiving six months of rain in two days.
Columbia, SC with its many waterways was a prime target for flooding and is one of the worst affected areas.
To make things more complicated, the American Society of Civil Engineers confirmed that a lot of the infrastructure was in pretty bad shape before the storm hit, with 1048 out of 9275 bridges declared structurally deficient.
“In the Columbia area, James Shirer saw the dam along Rockyford Lake in the town of Forest Acres fail Monday, causing the 22-acre lake to drain in 10 to 15 minutes.
“It just poured out,” Shirer said.
The lakes and ponds got so high, the dams couldn’t take it anymore, Shirer said. Speaking of the rains, he said, “They’ve wrecked the dams; they’ve ruined all of the bridges. This one lake has already gone from topping over this bridge to where it’s emptying out.”
As he spoke, water rushed through where the dam once was and a military helicopter circled overhead.
“It’s devastating for Columbia,” he said. “It’s one of the worst things we’ve seen.”
Officials have warned that some residents could be without potable water for days due to water main breaks and the capital city has told all of its 375,000 residents to boil water before drinking.
Inframanage.com notes that large natural events – earthquake, tsunami, hurricane/typhoon, volcanic activity, flooding are regular events, with the severity and frequency being the only factors that change.
Infrastructure is always vulnerable to large natural events.
As part of your infrastructure management planning, risk assessment of this vulnerability is important.
Infrastructure asset managers can then choose to protect infrastructure, build in redundancy, or take other risk mitigation measures. Reasonableness and affordability will be constraints on the actions undertaken.
There will always be, at some stage, a natural event that exceeds the planning parameters and mitigation measures, such as the flooding that has been experienced in South Carolina.
When these events happen, and infrastructure is inevitably damaged, contingency and response planning come to the fore.
The lessons from the damage from large natural events include the need for clear and frequent communication with the public and reasonable plans for the restoration of services – including temporary measures.
Plans and practice of coördination between the various local, state and federal response agencies will help in ensuring an optimal response to the event.
PHOTO & CAPTION CREDIT: North Charleston via Flickr Creative Commons License