A few weeks ago I noticed a 6″ diameter hole had suddenly appeared in the pavement over the culvert which the stream from the school flows into the canal. It’s on canal property, so I notified the Canal Authority and they sent out a truck to put some ‘cones’ up and a barrier to prevent vehicles and people having a mishap.
A few days later I looked under the cone which had been strategically placed over the hole, and discovered the hole had grown in size. The metal culvert pipe had corroded through, and the flow of water had washed out all the soil above. Overall the hole is about 6 feet deep and growing. Any vehicle traveling over this area would likely cause a collapse of the metal pipework. If anyone happened to fall down this, they’d be cut up pretty badly by the jagged metal pipes.
This is a small example of what can happen to a culvert. Fortunately, this isn’t underneath an embankment dam, but it does demonstrate the dilapidated state of the bridge. The surrounding concrete is a complete disaster, over half of the structure is missing, which is why the Canal Authority dumped a pile of small 6″ rock filler around the outlet. They washed out completely in the first storm, so they put in more of the same and once more it all washed away after another storm.
Finally, they brought in a truck load of rip-rap rocks, 2 feet diameter, and that has held. Unfortunately, it looks like they’re going to have to dig up the entire structure and replace the pipes.
If all the other culverts that are underneath embankment dams are in this condition, with even a small crack in concrete or corrosion in pipes, then we should all be very concerned because this sort of sinkhole could easily cause an embankment failure.
It’s Friday 12th January and it’s been thawing and raining today, with a fair amount of water flow occurring.
The hole has doubled in size over 24 hours.
Five days later, we now see that TWO pipes are rusted through!