Sheet Flow Construction Erosion Control

March 20, 2020

It’s in Here Somewhere

“How are we going to fix this?” Photo: David Jenkins

You can’t tell from the photo, but the outfall pipe is bent upward several feet. This pond was used to contain dirty construction site runoff until it could be treated and discharged, but allow for emergency overflow. To accomplish this, the contractor was required to install elbows and risers on the pond discharge pipes; they failed to properly secure them, only using cables tied to “eco blocks” on top of the pond (you can see the cables angling to the left from the risers). We suggested that they might want to add some weight to the pipes and plates at the bottom of the risers such that it would be impossible for them to move. They didn’t, we had days of rainfall, the pipes lifted and broke the connections to the next pipe sections, located well back in from the liner-covered slope. This required a significant amount of work to repair, including liner removal, excavation, pipe replacement, installation of controlled density fill, then hiring a specialized company to re-install the liner. The contractor paid the entire bill.

Temporary elbows and risers installed. Photo: David Jenkins
Temporary elbow and riser detail from contract documents.

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