Do you offer permeable curtains (lets the water flow throught the curtain) or only impermeable turbidity curtains?

(Michigan, USA)

I understand that your silt curtains are impermeable. Is that correct? Does your company offer permeable curtains (lets the water flow through the curtain) too?

Do the permeable curtains rest on the channel bottom (from reading the literature on the web site, it appears that the impermeable curtains are kept about 1 foot off the bottom).

How can I determine size, type, etc. of the silt curtains?