The Petitcodiac River in the Bay of Fundy has extensive experience of dams and barrages. These photos show graphically the alarming rate at which mud is deposited when the flow is slowed by and obstruction - in this case a causeway with a sluice gate. They experienced deposition rates of 1m per year!

The Petitcodiac River in 1954

The Petitcodiac River in 1996

What went wrong? Mud breeds mud. - more photos and details of the Petitcodiac experience.

The good news is that lessons have been learned. Due to the extent of the unforeseen silting problems and subsequent pressure of flooding, the causeway in now being removed and replaced with a bridge. It is hoped this will restore the river to a healthy and navigable state.