Blogs

Turbidity 1-25-250 NTUs

By Dave Jenkins posted 2 days ago
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Photo: Dave Jenkins, CPESC The sample on the left is just under 1 NTU , the middle is 25 NTUs, and the one on the right is 250 NTUs. In Washington state, the Construction Storm Water General NPDES Permit lists benchmarks that construction discharges must meet. These are: 0-25 NTUs everything is cool; 26 -249 NTUs not so good, upgrade your site best management practices ( BMPs ) and modify your SWPPP ; 250 NTUs and above, call the Dept. of Ecology , upgrade BMPs, modify the SWPPP and monitor the water body that the project discharges to until you are in compliance. #turbidity #NTU ​​​
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Sediment Trackout-Not What an Inspector Wants to See

By Dave Jenkins posted 9 days ago
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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 ...
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Bonded Fiber Matrix Needs to Cure

By Dave Jenkins posted 16 days ago
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Bonded Fiber Matrix (BFM) needs to dry for 24 to 36 hours before it rains or else it can start to wash off. Video: David Jenkins, CPESC
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Sand Bag Berm Part 3

By Dave Jenkins posted 21 days ago
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In this sand bag berm part 3 video I show the amount of rain runoff diverted away from a project versus the turbid site water. Video: David Jenkins, CPESC
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Sand Bag Berm, Part 2

By Dave Jenkins posted 22 days ago
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In this sand bag berm part 2 video I show the amount of rain runoff diverted away from a project compared to the water falling on the bare dirt of the project. #SandBag #Berm Video: Dave Jenkins, CPESC ​​
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Sand Bag Berm Part 1

By Dave Jenkins posted 23 days ago
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In this sand bag berm part 1 video I show the amount of rain runoff diverted away from a project. #SandBag #Berm Video: Dave Jenkins, CPESC ​​
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Knocking off Early

By Dave Jenkins posted 26 days ago
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We were working on a Superfund site one cold December night on the Duwamish River in Seattle. It started to snow and things got slippery. We knocked off early. Do you have photos of your work experiencesyou want to share?
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Constructing on Impervious Surfaces-BMPs for Water Quality and Quantity

By Dave Jenkins posted 28 days ago
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Yesterday, we hosted a webinar on the challenges of working on and around impervious surfaces; I have included the link. What have been your experiences with this? What BMPs have you used? Video link: https://youtu.be/-GWQ-FWi-Lc #BMPs #construction #impervious #runoff ​​​​​
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Rough vs. Smooth Slope

By Dave Jenkins posted 30 days ago
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This is a dramatic example of the effect of rainfall on a Rough vs Smooth slope. The rough side was “track walked” using a small Caterpiller tractor. The other side was “back-bladed” smooth with the same tractor. Both test plots were prepared with the same soil and then sprayed with bonded fiber matrix (BFM) with seed and fertilizer. Video: Dave Jenkins, CPESC
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Sediment Trackout Fail

By Dave Jenkins posted Dec 21, 2022
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I’m not a big fan of the “Grizzly” method of trackout prevention. My standard is “No visible trackout” and these have never met that standard. Preventing tires from getting dirty in the first place is still the best BMP! This is a trackout fail. Photo: Dave Jenkins, CPESC
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Construction Exit Fail

By Dave Jenkins posted Dec 14, 2022
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This is a 30 + acre site with one access point, this one. If this was my project, I would have specified a tire wash with an asphalt exit to the street. The tire wash would have been long enough for two tire rotations, have high pressure, low volume nozzles located such that all tire surfaces were sprayed. This system would also have an on-board, treatment polymer injection system to keep the tire wash water relatively clean. I would have specified that the water be tested for turbidity daily, measured at 50 NTUs or less. Since the water is classified as “process water”, I would have required it to be tested for metals and other contaminants, then hauled to an ...
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Temporary Irrigation for Better Grass Growth

By Dave Jenkins posted Dec 07, 2022
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This late-summer project needed to be seeded and have 90% grass cover befor the rainy season starting in fall. The contractor set up a temporary irrigation system to make sure that happened. Video: David Jenkins, CPESC
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Inspecting Construction Erosion Controls-Some Examples

By Dave Jenkins posted Dec 03, 2022
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Our October webinar, " Inspecting Construction Erosion Controls-Some Examples" is now posted on our chapter YouTube channel.
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Clean Water Diversion

By Dave Jenkins posted Nov 30, 2022
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Unrolled Asphalt Berm Edge for Clean Water Diversion – Here is a cool trick for keeping clean water out of your project. The contractor put down asphalt but didn’t roll (compact) the edge, which left a 3 or 4 inch berm. Clean rain water was kept on the asphalt rather than flowing off into the dirt shoulder and disturbed areas. Video: Dave Jenkins, CPESC
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Summer Internships in Oregon

By Dave Jenkins posted Nov 23, 2022
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Civil Engineering Intern - 2023 Portland Civil + Survey Civil Engineering Internship – 2023 We have 3 Summer Internship positions available, which run May-August or June-September (depending on the student’s school schedule). A successful intern in our program is someone who enjoys being challenged -- you will be integrated into a team with coworkers ready to share their professional experience as you work on projects together. You will be working with PEs and Civil Designers and will be utilizing Civil3D beginning on your first day here. There will be opportunities for design, plan production, research, and site visits (with the necessary ...
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Keep Straw Out of Catch Basin

By Dave Jenkins posted Nov 23, 2022
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This video shows a wattle installed around a catch basin to keep straw out that has been placed as soil cover. Video: Dave Jenkins, CPESC
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Straw Wattles Reduce Erosion

By Dave Jenkins posted Nov 16, 2022
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Video: David Jenkins This is a video I took a year after these straw wattles were installed on a slope to reduce erosion.
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Curb Inlet Protection

By Dave Jenkins posted Nov 09, 2022
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Curb Inlet Protection According to the Minnesota Stormwater Manual : “Curb Inlet protection devices intercept and/or filter sediment before it can be transported from a site into the storm drain system and discharged into a lake, river, stream, wetland, or other waterbody. These devices also keep sediment from filling or clogging storm drain pipes, ditches, and downgradient sediment traps or ponds. Inlet protection may also include placement of a barrier to create a bypass of an inlet transferring flow downstream to a sediment trap, basin, or other inlet discharging to a non-critical area.” Nothing wrong with sediment control BMPs, as they are ...
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Straw Wattle Instead of Silt Fence

By Dave Jenkins posted Nov 02, 2022
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Tags: construction erosion and sediment control, silt fence, straw Wattle On some small projects, with low risk for erosion of sediment into a creek or other Waters of the United States, silt fence is overkill and will just end up in the landfill when the project is done. In this case, straw wattles work just fine. Video: Dave Jenkins, CPESC
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Migratory Bird Treaty Act Nest  Removal

By Dave Jenkins posted Oct 26, 2022
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Tags: BMPs, building demolition,contract specifications, demolition, eggs, Migratory Bird Treaty Act, migratory birds, nest removal, seagulls, specifications, waterfront Seaport building demolition scheduled for spring summer. Starting in April or May, seagulls begin nesting. When seagulls nest and lay eggs, you can’t demolish the buildings until you apply for and get permission for a “Take” of a bird covered under the Migratory Bird Treaty Act. This takes time, holds up the contractor, everyone gets frustrated. In order to head this off, I wrote some contract specifications: Photo: Port of Seattle NESTING BIRD WATCH AND ...
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