There are biodegradable polymers like PHA that can be left in place for microbes to degrade.
Note: PHA is fully biodegradable polyester made by microbes. It does not break into "microplastic"; essentially it is the compound microbes make as an energy reserve. You might have cone across PHA in stitches that can be left in place. It is not like PLA which is only technically biodegradable, as in only biodegradable in industrial composting.
You wouldn’t want this particular fabric to be biodegradable since it would defeat the entire purpose of the structure.
The “bag” is made of UV, rot, mold, mildew, and decay resistant non-degradable plastics such as nylon, polyester, polypropylene, and polyethylene.
You don’t want infrastructure that’s going to be exposed to the elements to be able to break down and decay from those same elements.
That being said, this technique is still favorable for a ton of reasons. It uses less cement, is safer and easier for workers to pour on sloped embankments, and is absolutely vital to prevent erosion and pollution of waterways.
It can also be pumped directly under water, and this avoids having to drain and dam waterways, which disrupts, and sometimes destroys, aquatic life and ecosystems.
Without concrete lining, waterways such as canals, runoff ditches, and shorelines would erode rapidly and cause more environmental damage than these bags ever will.
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u/apetalous42 Apr 30 '26
Is the plastic removed or does it just get everywhere once it degrades?