- Crews have been filling cracks in Oroville Dam main spillway with concrete and hoping it will hold for years
- They reported it as safe in several reports since 2009 before the dam threatened catastrophe last week
- The enormous hole in the main chute compromised the dam’s drainage function as water in its reservoir rose
- It forced engineers to turn to a never-before-used emergency spillway which buckled under the pressure
- The total cost of the damage, which engineers are now frantically fixing, is estimated to be $100million
- Residents who had been evacuated were allowed home on Tuesday but must be ready to flee again
- More rain and strong winds are on the way, threatening to fill the lake back up and hamper the repairs
Engineers had been using ‘patch and pray’ techniques to repair California’s crumbling Oroville Dam before it threatened to collapse last week and sent the region into a panic.
Cracks in the main concrete spillway have been included in site reports since 2009 but crews have been using quick-fix concrete solutions to try to stop them from getting worse.
Engineering experts described the effort as a ‘patch and pray’ approach on Wednesday as the emergency situation in Oroville persisted.
200,000 people were suddenly evacuated on Sunday when the California Department of Water Resources dramatically announced that an emergency spillway at the dam was an hour away from collapse.
Since then, crews have been working round the clock to beef it back up by lining it with boulders and are racing against oncoming storms which may hamper their efforts.
Residents nervously returned home as the evacuation order was downgraded to a warning on Tuesday but they have been told to be ready to flee again at a moment’s notice if the volatile situation turns on its head again.