How will the AHS control sea lampreys?  By

How will the AHS control sea lampreys?

The adjustable hydraulic structure (AHS) is a uniquely designed sea lamprey control mechanism which incorporates both inflatable and velocity barrier components to accomplish multiple goals, including flood conveyance and sea lamprey control. The AHS relies on prohibitive water velocity to prevent upstream sea lamprey migration during times when the gates must be lowered to accommodate high flow events.