Sheetflow Erosion and Sediment Control

June 24, 2020

Silt Fence and Trackout Fail Part 2

This is a follow up to Silt Fence and Trackout Fail post from April 6, 2020. Same old !@#$, different month.

Photo: David Jenkins
Photo: David Jenkins

May 28, 2020

Prevented Trackout

Photo: David Jenkins

Grizzlies were placed from the road back into the site where gravel borrow fill and rip rap were needed. The delivery trucks were singles, no trailers, and backed up to the steel plate near the excavator and dumped. The excavator moved the material into the proper piles. The truck tires came in clean from the paved road, stayed clean on the grizzlies and left clean. No need for a tire wash, just some thought and planning.

May 27, 2020

Preventable Trackout

Photo: David Jenkins

Asphalt was removed to work on the new building foundation. Driveway asphalt was left in place, which is good. Gravel base course was delivered to be placed under the concrete slab. Instead of backing all of the way into the site, over wet dirt, they could have stayed on the asphalt driveway to unload and used site equipment to move the gravel. It is possible that the gravel came in trucks with trailers in which case backing all of the way in was probably necessary to avoid blocking traffic on a fairly busy street. With some added cost, single dump trucks could be used as described above and prevented the track out. While this is not a lot of dirt on the road, it does add up and is a magnet for inspectors and regulators to visit the site. The contractor could also have dumped gravel next to the asphalt, then graded it back into the site to provide a construction access into the site. In this way, the delivery truck, even with trailer, could have stayed on gravel rather than driving on dirt.

April 7, 2020

Silt Fence Water Bars Fail

Photo: David Jenkins

Whenever I see something like this, it makes me think that the site owner/contractor either didn’t know what they were doing or bit off more project than they could chew, or both. These guys cleared, grubbed and graded something over 80 acres starting in late summer, failed to phase the work, failed to use soil cover practices, failed to listen to the experts and got nailed by the fall rains.

Erosion control is really about water control: reducing volume, preventing it from becoming turbid, and controlling where it goes. By the time the rains hit this project, there was too much water, it was too dirty, and there were too few options for controlling where it went.

In addition, they refused to set up a chitosan-enhanced sand filtration system to treat and discharge water; this left them no options and too much turbid water that had nowhere to go. As a result, they hammered a wetland, were fined heavily, and were shut down for months.

Silt fences are not meant to control water, convey water, filter water; they are designed to control eroded sediment. Ditches, berms (rock, gravel, triangular silt dikes, etc.) would have been better choices at this location. Not opening up so much area so late in the season would have been the best option. Their means and methods did not save them time or money.

April 6, 2020

Silt Fence and Trackout Fail

Photo: David Jenkins

Just minding my own business last Friday, driving from Fred Meyer to the UPS store and passed this project. Told my wife I have to get a photo, she says okay since she knows me and my habit of stopping to take TESC photos. Made a u turn at the Wal Mart, drove back a block and stopped in the middle of the street to get this shot.

There is so much wrong here, where do I start? Clearly, dirt is being tracked off of the project in the background as you can see the sediment build up in the curb line. Someone told someone to put something in the swale to keep dirt out. Someone installed this silt fence.

First off, silt fence needs to be trenched in and this just has a few rocks placed on the flap.

Second, they probably couldn’t trench this in anyway without tearing up the drainage swale.

Third, only two of the three curb cuts are backed by the silt fence.

Fourth, silt fence is a barrier, not a filter, and with the volume of water draining off the asphalt during a rain event, dirty water would just blow around and under the silt fence.

Conclusion, silt fence is never used in a water flow situation; it is only to contain eroded sediment from a sloped area. A better BMP here is a compost berm or something similar that would allow some water to pass but filter some sediment. Sand bags would work to keep everything out of the swale but then the dirty water would bypass to the next catch basin, which probably has a catch basin insert, which would collect sand and such but would not do anything for turbidity. So, what is the best BMP? Stop the !@#$ ing trackout in the first place!

April 2, 2020

Muddy Puddle Inside the Project

Photo: David Jenkins

Is this a problem if it is completely contained within a project boundary? Unless vehicles are driving through this and tracking mud outside of the project, I don’t consider it a problem and would only caution the contractor to watch out for trackout.

February 20, 2020

Just a Little Trackout

August 13, 2019

The Soaker Tire wash

These are great as long as the tires are not too muddy, the mud is not too sticky and the vehicle load is not too high. Most of the water is directed to the sidewalls and misses much of the mud hiding in the treads. These work great as the final , clean rinse cycle in conjunction with a tire bath best management practice. Chemical flocculants can be added to the water to remove much of the sediment load. Web site: www.sheetflow.com

Description from the website: http://www.thesoaker.com/

“The Soaker” is a portable, self-contained and environmentally friendly wheel washing system. The system does not require city power or water connected to it which makes it highly portable.

“The Soaker” can be installed on job sites, dump sites and material pits to help keep the surrounding streets free of mud and dirt.

Its aluminum and stainless steel construction makes “The Soaker” environmentally friendly.

It features a high capacity main tank of 4000 gallons and a reserve tank of 2000 gallons. Its adjustable spray heads provide a low pressure/high volume water stream of up to 1000gpm. Motion sensors detect the vehicles on approach and turn on the pumps so the water spray is at full power by the time the vehicles go through the wheel wash.

“The Soaker” is manufactured to provide solutions to problems such as portability, road pollution, costly cleaning processes, fines and violations for depositing debris onto public highways, etc…

“The Soaker” can be rented on a monthly basis or purchased. A lease purchase option is also available. For more information about “The Soaker” wheel washing system, please call us at: (818) 952-6752 or email at: soakerinfo@thesoaker.com

May 25, 2015

Tire Bath

One of the most difficult things to manage on a construction project, especially a road project, is preventing mud from being tracked off the job. This video illustrates the use of a water-filled tire bath along with a rock entrance road and rock and asphalt exit onto existing road surface. Tire baths are useful when the there is a minimal amount of traffic leaving the project. Tire baths require a lot of maintenance including water changes and sediment removal.

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