Here are some salient points - emphasis added:
At public meetings since the disaster, D.C. Water chief executive David Gadis has said the utility was aware of corrosion or “thinning” of the concrete pipe at the point of the collapse. But he said the utility had graded the corrosion at that location as “moderate” and had seen no clear indication it was in immediate danger.
D.C. Water’s engineers have said they cannot yet determine if corrosion was a factor in the collapse, but they are investigating whether large boulders used to bury the pipe when it was constructed in 1962 created pressure points that precipitated its failure. The spill was exacerbated, Gadis said, by large rocks that fell into the pipe after it broke apart, blocking the flow of wastewater and forcing it to shoot up through a manhole.
So there's a 64 year old trunk sewer line made out of concrete pipe that has been inspected and is known to have weak points/corrosion, and the EPA and sewer agency have been jacking each other off for 7 years? At face value, I'll heap the blame on the Park Service's envirotards. I don't care if the sewer agency made plan changes: that's what happens as the design process progresses and gets refined.
Here's the thing: Trunk sewers like this have a lot of flow, and generally produce some amount of hydrogen sulfide - a very corrosive substance. Coating systems for concrete pipe have been around for over a hundred years - bitumen being the most predominant 60 years ago. Epoxy and other synthetic coatings and linings are now the norm, and may get you a design life in excess of 50 years.
However the fact that corrosion and degradation of the pipe had been previously identified - combined with its age - should have fast tracked this project. Instead inordinate delays and bureaucratic bullshit resulted in swimming pools full of turd soup polluting DC.
In some regards it's a fitting tribute to our government, but mostly it just makes me shake my head.