Sheetflow Erosion & Sediment Control Heavy Civil Construction

September 16, 2020

Catch Basin Covered with 30 mil PVC

Photo: David Jenkins

This catch basin in a live storm system sits right in the middle of an actively worked area. Plugging the discharge pipe wasn’t possible due to depth and access of the manhole. The solution is placing heavy 30 mil PVC liner material under the grate then telling all of the workers that they are not to poke holes in it when the area floods from rain.

July 31, 2020

Catch Basin Covered-Infiltration

catch basin covered to allow infiltration of construction stormwater in hole cut in asphalt and filled with rock
Photo: David Jenkins

This is the first project we have cut asphalt to allow construction stormwater to infiltrate. The area is paved, flat. The sweeper runs constantly but the water is still too turbid to go down the drain. The fill soil under the asphalt is sandy. If we just covered the catch basin with 30 Mil PVC, the area would just flood, then drain to another catch basin. Solution? Cut out a section of asphalt full depth to the sandy soil, fill with 3 to 5 inch rock. This way the water infiltrates but vehicles can drive over the hole. This is working really well so we will be doing this on future container dock upgrade projects.

October 30, 2019

Open Catch Basin Fixed Again

Back where we started, 30 mil PVC blocking the catch basin. Photo: David Jenkins

As of two days ago, there is new 30 mil PVC under the catch basin grate and turbid water is not draining into the catch basin. The contractor told their staff not to puncture the PVC. No word on whether they are thinking more proactively about this. The best measure is to keep the stockpile covered and the area cleaned up. We shall see what’s next.

October 29, 2019

Open Catch Basin Open Again

Why, this was flooded yesterday, what happened? Photo: David Jenkins

The saga continues… the next inspection looked like the first inspection. 500 + NTU water draining into the catch basin. What happened?

30 mil PVC punctured to let water drain. Photo: David Jenkins

As suspected, someone didn’t like the flooding, so they punctured the 30 mil PVC. I am wondering why the contractor erosion control lead is not finding this.

October 28, 2019

Open Catch Basin Fixed?

Catch Basin Blocked with 30 mil PVC Photo: David Jenkins

I inspected the open catch basin the next day, and this is what the contractor had done to keep turbid water out. I have nothing against doing this, but, since this does keep water out, flooding ensues. Flooding is okay if the catch basin is in a low spot and no one needs to work in the area.

I told the contractor that they might want to look at the storm system and see if there is a point where they can install a concrete plug temporarily and use the system for conveying the turbid water to their treatment system.

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