Sheetflow Erosion and Sediment Control

March 26, 2020

Roof Drains and Bare Soil

Photo: David Jenkins

Thousands of gallons of clean rainwater draining off the roof deck onto bare soil turning into thousands of gallons of water that’s too dirty to discharge without treatment. With pre-planning, a temporary collection system could have been developed and installed to contain, collect and convey the clean water to an existing drainage system. Without such a system, the dirty water had to be treated chemically to reduce the turbidity enough to discharge to the storm system.

October 28, 2019

Open Catch Basin Fixed?

Catch Basin Blocked with 30 mil PVC Photo: David Jenkins

I inspected the open catch basin the next day, and this is what the contractor had done to keep turbid water out. I have nothing against doing this, but, since this does keep water out, flooding ensues. Flooding is okay if the catch basin is in a low spot and no one needs to work in the area.

I told the contractor that they might want to look at the storm system and see if there is a point where they can install a concrete plug temporarily and use the system for conveying the turbid water to their treatment system.

October 4, 2019

Broken Waterline

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.
Photo: David Jenkins

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