Waterway Weirs

You would think with this amount of water flowing downstream that it would be impossible to kayak up to this small lowhead dam (known as a "weir" in Mobile) against the current. Wrong.

Hydraulic backwash is a hidden dangerous characteristic of lowhead dams or weirs. The backwash actually draws objects toward the waterfall. It is nearly impossible to escape the strength of the hydraulic spin zone action after an object like a kayak or person gets sucked into a lowhead dam waterfall during heavy water flow.

Lowhead dams are also called "Drowning Machines." Luckily the lowhead dam here on Montlimar Creek where it meets Moore Creek by Halls Mill Road normally flows at a trickle like seen in the above photo so the hydraulic spinning forces are weak. Even during weak flow the forces were still strong enough to draw the kayak to the waterfall.

This above photo is the same weir drop off when the water levels were higher due to rain runoff. You can actually see a dip in the water level just past the water fall.

Again, same weir (lowhead dam) location on Montlimar Creek after a heavy rain. In this view you can see a football and other trash trapped by the waterfall hydraulic action. The football kept getting sucked under water and then it would pop back up for a few seconds only to be sucked back under water again.

The same deadly trapped spinning action would happen to a kayak or a person or even a motorboat if any of them got near this lowhead dam during similar creek water levels.

The pathetic thing is not a single lowhead dam in Montlimar Creek or Three Mile Creek in Mobile has a warning sign to alert upstream kayakers or canoeists to the presence of the downstream lowhead dams. That is the Ugly truth. The City of Mobile is going to wait for someone to die before it will put up signs to warn waterway users of the deadly lowhead dam hazards.