You can’t get a good seal with a sand bag berm. Dirty water down the drain.
June 30, 2020
Sand Bag Berm Around Catch Basin
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May 7, 2020
Turbidity 1-25-250 NTUs
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.
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February 25, 2020
Construction Erosion Inspection-Turbid Discharge
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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October 29, 2019
Open Catch Basin Open Again
The saga continues… the next inspection looked like the first inspection. The open catch basin is open again. 500 + NTU water draining into the catch basin. What happened?
As suspected, someone didn’t like the flooding, so they punctured the 30 mil PVC. I am wondering why the contractor erosion control lead is not finding this.
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October 27, 2019
Open Catch Basin
I found this open catch basin during a construction erosion inspection. The turbidity of the water draining into it from the stockpile measured at over 600 NTUs. Note that there is an insert in the catch basin; these do nothing to reduce turbidity. I notified the contractor who should have found this in their daily inspections, which I pointed out to them.
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October 4, 2019
Broken Waterline
This is caused by a broken 16 inch waterline. Fortunately, all of the muddy water was contained in a 72″ storm pipe with a valve. Water was then pumped to a Chitosan-enhanced Sand Filtration (CESF) system for treatment to 5 NTUs for discharge to a creek. Knowing this project was going to be constructed over several winter seasons, we specified the CESF system in the contract.
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