That’s a great question, and the answer depends largely on the source of the silt and sediment that is being contained, and whether it contains anything toxic that cannot remain in the environment. In most cases, though, the answer tends towards no. The vast majority of settled sediment in a waterway remains that way, so the process of detaining additional silt and sediment and giving it a chance to settle is usually enough to maintain water quality. Any sort of activity that disturbs the accumulated sediment risks triggering another Of course, as in all things, there are some exceptions.
If your on-site inspector or permitting authorities require removal, then that’s your answer. If you’re noticing that the curtain appears to be leaking sediment or the curtain has somehow managed to become trapped on the bottom by accumulated sediment, then it will absolutely have to be freed before the curtain itself is damaged. In most cases, sediment can be removed by using a debris pump to pull it from within the containment area and deposit it in dewatering bags. These are essentially filter bags, which trap sediment within and allow clean water to flow out, so situate them in a place that will allow the water to flow to the original body of water (without picking up more dirt!). Repeat this process until the sediment build up has been adequately reduced. If your curtain was trapped, make sure that it reaches no closer than 12” to the bottom of the waterway to prevent recurrence.
