Lock and dam FAQs
FMR is excited about the opportunity to reimagine the gorge with dams removed and rapids tumbling. We're eager to engage in a thoughtful, science-based exploration and broad community discussion about the possibility of this new vision.
As our community considers dam removal, many important questions must be answered. We’ve compiled this brief overview or FAQ to answer some of the most pressing questions.
Frequently Asked Questions
Is the lock and dam at Upper St. Anthony Falls being considered for removal?
No. The current disposition study is only concerned with Lower St. Anthony Falls (downstream from the falls) and Lock and Dam No. 1.
Would the removal of Lower St. Anthony Falls and Lock & Dam No. 1 affect the Twin Cities' drinking water supply?
No. Water intake from the Mississippi River for drinking water is located upstream of St. Anthony Falls and would not be affected.
Would dam removal mean invasive carp would move more easily upstream?
Not necessarily. The closure of the Upper St. Anthony Falls lock should be very helpful in preventing the carp from moving the headwaters, as the dam itself is tall enough to prevent the carp from getting over it. Unfortunately, Lock and Dam No. 1 is not tall enough to prevent their movement upstream to St. Anthony Falls. Regardless of whether we remove Lower St. Anthony Falls lock and dam or Lock and Dam 1, we need barriers and other prevention activities further downstream in southern Minnesota. We are also interested in better understanding how restoring the river’s ecosystem and its native fish and mussel populations might prevent invasive carp from taking hold in this stretch of the river since there would be a more diverse and competitive habitat they might struggle more to survive in.
Would water levels drop if the dams were removed?
Yes. The river would drop around 30 feet with the removal of Lower St. Anthony Falls and Lock and Dam No. 1. It would look similar to the water level on the other side of the dam farther downstream from Lock and Dam No. 1. Check out these visualizations of what the river might look like if the dams were removed.
Would removing the dams make the Twin Cities more prone to flooding?
Not likely. Neither Lower St. Anthony Falls nor Lock and Dam No. 1 were built for the purpose of flood control. Although we do not know how climate change might affect this, the removal of either dam would lower water levels, making flooding less of a concern.
Can the locks be reopened for commercial traffic?
No. Upper St. Anthony Falls was closed in 2015 to prevent the spread of invasive carp into the headwaters of the Mississippi River. There are no more commercial docks in Minneapolis and barge traffic has ended in this stretch of the river. Barge traffic will only go as far north as downtown St. Paul.
Why are hydroelectric dams not necessarily good for the environment?
Although hydroelectricity is a renewable resource and carbon-free, because dams erase the natural habitat and drastically affect the ecosystem, they are not necessarily considered to be a “green” form of energy. The loss of the Mississippi river gorge’s rapids due to the dams being built removed the shallower and more oxygenated habitat many native fish and mussel species were dependent upon in order to survive and reproduce effectively. Many dam removals across the country have seen the return of these native fish and mussel populations with the restoration of their habitats.
Does FMR have a position on dam removal?
We are excited to engage in and support a thoughtful, science-based exploration and broad community discussion. Learn more.