Sheet Flow Construction Erosion Control

November 24, 2020

Creative Slop Bin

Video: David Jenkins-Sheetflow Erosion Control

I call it a creative slop bin but really it’s an old loading dock. We had to do a storm system repair and needed a place close to the work to hold the vactor slurry temporarily. The catch basin grate has plastic under it.

November 23, 2020

Erosion Controls in Olympic National Park

Video: David Jenkins-Sheetflow Erosion Contr

Recently, I stopped to check out erosion controls on the way to the Staircase in Olympic National Park.

November 20, 2020

Bubbling Crude

Photo: David Jenkins-Sheetflow Erosion Control

This “bubbling crude” could be from an episode of ” The Beverly Hillbillies”, but it isn’t. This is oil from a leaking underground storage tank we found on a Superfund cleanup project.

November 19, 2020

A Rare Beast

Photo: David Jenkins-Sheetflow Erosion Control

Here is a rare beast: a vacuum sweeper with working spray nozzles and nothing dripping out of the back.

This has been such a problem that I included the following language in my erosion control specification:

1.) Vacuum sweepers shall have on-board water spray systems operating at all times.  

2.) Sweeper systems shall function per manufacturer specifications including, but not limited to, water spray systems, blowers, vacuum nozzles, hoses, debris hopper, hydraulics and electrical.

3.) At no time shall debris hopper seals leak debris and/or liquids

November 18, 2020

The Problem with Hosing Tires

Photo: David Jenkins-Sheetflow Erosion Control
Photo: David Jenkins-Sheetflow Erosion Control

What is the problem with hosing tires? Water-specifically “Process Water”. Water that is used in a process, like hosing tires, is classified as process water and must be dealt with as though it is contaminated; because it is, with oil, grease, and various metals. So, if you are going to hose tires, you must plan to collect and dispose of the water legally. Legal disposal means a special processor for treatment and discharge or sanitary sewer.

November 16, 2020

A Final Inspection

I am conducting a final inspection of erosion controls at a former staging area. Some of the best management practices shown are: silt fence, straw wattles, and hydroseed.

Video: David Jenkins-Sheetflow Erosion Control

November 4, 2020

Silt Fence Inspection

Filed under: Photo — Tags: , , , , , , — Sheetflow @ 6:53 am
Photo: David Jenkins-Sheetflow Erosion Control

This silt fence looks pretty ugly and inspection shows it certainly needs maintenance; but does it? The silt fence made sense before we excavated several feet, now it doesn’t. There is a turbidity curtain in the river to the right and the contractor is careful to pull material back from the riverbank. I am going to let this go.

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.

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