Sheetflow Erosion Control Erosion Control for CESCL's

May 4, 2020

Drive-by Silt Fence Inspection

Video: David Jenkins

It doesn’t take more than a few seconds during a drive-by inspection to see that this silt fence has problems. While the risk of sediment discharge is low, the condition of the fence says to me ” We don’t really think this TESC stuff is all that necessary.” If it was my job to inspect, I would be making a “U” turn to have a chat.

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.

February 25, 2020

Construction Erosion Inspection-Turbid Discharge

6000 NTUs Photo: David Jenkins

My construction erosion inspection turned up a turbid discharge. A little bit of sediment track out each day builds up. The contractor was vacuum sweeping this area on a regular basis but the first rain shows how effective that was. I measured this discharge at 6000 nephelometric turbidity units (NTUs) using an old Hach 2100P turbidimeter. This meter only reads up to 1000 NTUs, so I had to dilute the sample 3 times to determine the actual reading.

February 14, 2020

Construction Erosion Inspection-Site Looks Bad but No Dirty Discharge

It looks like a dirty, poorly managed site on first inspection, but is it really? When you get the whole story this project turns out have a low risk for water quality compliance violations.

 

Video: David Jenkins

December 3, 2019

Construction Erosion Inspection-Trench Excavation Asphalt Kept Clean

Dirt from trench excavation loaded into front loader bucket and hauled to stockpile, or dirt side cast onto asphalt: which is cheaper? How about no sweeper needed, no dirty water going down the drain, asphalt kept clean?  I go with the first answer.

 

Video: David Jenkins

October 15, 2019

Inspection June 2013

This is a video I took during a construction erosion control inspection in June 2013.

September 25, 2019

Not What an Inspector Wants to See

I just did a quick, random, drive-by of a job and this is what I as the inspector saw. This might tell me that the construction staff, owner and contractor, don’t understand what is required or, haven’t read the TESC specifications.

Since this was a random, unannounced, drive-by, I might think that this is not an isolated incident. While I prefer a site be kept clean, as long as stuff doesn’t leave the project boundary, I don’t have an issue. However, by not keeping the site clean, trackout is inevitable.

Also, note the Bobcat broom sweeper just inside the fence on the left; these are great for pushing dirt around and up in the air but we only allow vacuum sweepers on projects, so I don’t know why this is on site.

I sent an email to the engineer suggesting that everyone might want to review the TESC spec. and take necessary actions so this doesn’t keep happening. Also, rain is forecast for tonight.

The fence line is the project boundary. Photo: David Jenkins
This is a visible, inspector magnet, just inviting increased scrutiny. Photo: David Jenkins

May 14, 2018

Geotextile-Foam Check Dam

Yet another example of poorly installed and maintained check dams. Even worse, it’s hard to install geotextile-foam check dams incorrectly. Here is an installation detail to use as a guide for proper installation:Geotextile-encased Check Dam

Video: David Jenkins

April 1, 2017

BFM Uniform Coverage

How to inspect bonded fiber matrix (BFM) application to verify uniform coverage.

Video: David Jenkins

May 17, 2016

Inspecting-Check Dams Need Low Center Point

Check dams need to be installed with a low center point.  This means  that the center of the dam is at least 6 to 8 inches lower than the outside edge; 12 inches in areas where intense rainfall occurs. If the center is higher than the outer edges, water will run around the dam and erode the side slopes of the ditch, causing erosion. If the ditch is shallow and you are using triangular silt dikes, you might need to add sand bags to create a point that is lower than the center.

Video: David Jenkins
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