Sheet Flow Construction Erosion Control

October 21, 2019

“Means and Methods” vs. Best Management Practices

Demolition of landside crane rail on a shipping container terminal.

In my experience, managing contractor “means and methods” is more important than using the “right” best management practices. When turbidity is the standard for measuring water quality compliance, as in Washington state, site cleanliness is the key to prevention and compliance.

This contract requires that catch basin inserts be installed in all catch basins within the project boundaries. However, inserts are not at all effective in reducing turbidity in runoff. While removing the crane rail on this container terminal project, the contractor could clean up as the work progresses, place all material removed from the trench onto plastic for later removal, load into a Bobcat bucket, and pick up small debris with a shop vac. I can require these things in the contract that the contractor bids. It may cost extra; the extra cost may be worth it if it reduces my risk. If I tell the contractor after the contract is awarded, I will pay more.

I can also make suggestions during the work, pointing out that keeping things really clean will keep them in compliance with their NPDES permit. If framed in a way that shows benefit to the contractor, meaning reducing risk and cost, they will probably follow the suggestion.

September 17, 2019

Can’t Get Away From It

I can’t get away from it. It doesn’t matter where I go, I always see some type of construction erosion issue. I went to visit relatives in Portland, Maine, flying in and out of Boston Logan International. In the terminal, waiting for my flight back home, I saw a construction project on the ramp; it had rained a few says before, hard. Obviously, the stockpile had not been covered before the storm and sediment washed off the pile into the drain.

I work at an airport that operates under strict turbidity effluent limits; here is how we do this kind of work:

(1) rarely do we allow stockpiles on the ramp because we rarely reuse the excavated material (it is either contaminated, unsuitable or doesn’t meet current FAA requirements); it is direct loaded into trucks and hauled off. When we do stockpile, we place dirt on plastic and cover it with plastic, using lots of sand bags to secure it from jet blast and wind.

(2) work areas are always isolated so there is no runoff from the site. Normally, we use four-inch extruded asphalt curbing along the base of the jersey barriers. Rolled hot mix asphalt (HMA) is used at the entrance point so water is contained but vehicles can access the site.  Water that builds up inside the curbing is pumped back into the excavation if clean, or a tank if contaminated.

I should have mentioned that we also have strict sediment trackout requirements: no visible sediment leaves the site at any time.  This is both because of the effluent limits and for safety reasons; dirt and debris that gets sucked up into a jet engine is damaging and possibly deadly.

Lastly, I am not casting aspersions on the folks at Logan; I don’t know their situation, permits, drainage system, or tolerance for risk.  Because of my situation, I have low risk tolerance for potential non-compliance with our permit and I notice when something would cause me grief at my airport.

January 14, 2019

Bonded Fiber Matrix (BFM)

Bonded Fiber Matrix (BFM) needs to dry for 24 to 36 hours before it rains or else it can start to wash off.

December 30, 2011

Pumping to Dirt Bag Doesn’t Reduce Turbidity of the Water

I know, great name for an erosion and sediment control product, right? Dirt bags work great if you are trying to reduce the total amount of sediment being discharged from a project. But, if you have to reduce the turbidity of the water to meet water quality standards, this won’t do it.

 

Video: David Jenkins

February 25, 2011

Construction Stormwater General Permit

Construction Stormwater General Permit

Construction site operators are required to be covered by a Construction Stormwater General Permit if they are engaged in clearing, grading, and excavating activities that disturb one or more acres and discharge stormwater to surface waters of the state. Smaller sites may also require coverage if they are part of a larger common plan of development that will ultimately disturb one acre or more. Operators of regulated construction sites are required to:

  • Develop stormwater pollution prevention plans.
  • Implement sediment, erosion, and pollution prevention control measures.
  • Obtain coverage under this permit.

NEW! - 01/29/09 Ecology issues the Construction Stormwater General Permit December 1, 2010

WebDMRs and PARIS

Contact Us – Contact your Permit Administrator for permit assistance or your Regional Office for site specific questions.

Permit, Forms and Application – Permit, application, forms, and appeal information.

High Turbidity Reporting – Construction projects must report high stormwater turbidity results within 24 hours.  If you get a high result, call your Ecology regional office.

Resources and Guidance – DMRs, Stormwater monitoring,  manuals, 303(d) list information.

CESCL Training and Certification Programs

Historical Information – Pollution Control Hearing Board information, public comments.

Construction Stormwater General Permit.

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