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Green Bay, WI 54229-9565
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Hydropower Planning

Praire du Sac Hydropower Dam and Fishway

Frequently Asked Questions


Prairie du Sac, Wisconsin, hydropower dam on the Wisconsin River

Prairie du Sac hydropower dam on the Wisconsin River.

Photo by USFWS; Nick Utrup

1. What action is the U.S. Fish and Wildlife Service taking?

The U.S. Fish and Wildlife Service is preparing an Environmental Assessment, in accordance with the National Environmental Policy Act, to evaluate the environmental consequences of fish passage at the Prairie du Sac dam. Wisconsin Power and Light Company operates the dam pursuant to a license issued by the Federal Energy Regulatory Commission, which includes a fish passage requirement.  The Service is responsible for approving a fish passage design that Wisconsin Power and Light Company develops pursuant to the license.


To start the Environmental Assessment process, the Service opened a public scoping period and held a public scoping open house to provide interested and affected parties an opportunity to learn more about the fishway project, to offer information and concerns and to become involved.  Input from the public is important and will help us identify and address impacts that may result from the project.  The public comment period for scoping closed August 1, 2013.


The public will also have an opportunity to review and comment on the draft Environmental Assessment before it is finalized.


2. Why does Wisconsin Power and Light Company need to build a fishway at Prairie du Sac Dam?

Unimpeded movement of native fish, such as lake sturgeon and paddlefish, was blocked when the Prairie du Sac Dam was constructed almost 100 years ago.  During the hydropower licensing process, the Service required that providing native fish access to more than 100 miles of habitat be included as a condition in the license, which was issued in 2002.  Providing access to a variety of habitats in the Wisconsin River upstream of the dam is beneficial to native fish and would likely improve both fish and mussel populations, thereby increasing opportunities for recreational angling and potentially creating jobs.


3. What species of fish need to pass?

All native fish species would benefit from passage at Prairie du Sac Dam; however, we would only recommend passage of those fish species that comply with State of Wisconsin rules and regulations.  Our primary target species include lake sturgeon, paddlefish, blue sucker and shovelnose sturgeon.


4. Does this include both upstream and downstream passage?

Yes, all alternatives for fish passage must incorporate an upstream component as well as a downstream component.  Downstream passage is already occurring at the Prairie du Sac Dam through the spillway gates, but we hope to make downstream passage safe, timely and effective by providing an engineered bypass.


5. How would fish be passed above the dam?

A range of options are being considered for passing fish from downstream of the dam to upstream.  Among these include both traditional and non-traditional fish passage methods that incorporate some ability to maintain a barrier to upstream movement of invasive species, such as Asian carp (Hypophthalmichthys spp.), and diseases of concern.


A website that does a good job describing each common type of fishway can be found at www.dpi.nsw.gov.au/fisheries/habitat/rehabilitating/fishways


6. What are the benefits of fish passage at Prairie du Sac Dam?

Providing fish passage at the Prairie du Sac Dam allows native fish to access high quality habitat both upstream and downstream of the dam.  We anticipate that fish populations, some of them of special concern, such as lake sturgeon and paddlefish, will improve as they begin to use these additional habitats.  Reconnecting downstream and upstream fish populations will also benefit the fisheries by increasing genetic mixing, thereby strengthening resilience of populations.  Strengthened fish populations will increase recreational fishing opportunities, which should increase angling-related revenue.  This, in turn, would improve local economies and create jobs.


Additionally, each species of native mussel, which are important elements of the Wisconsin River ecosystem, depends on certain fish species to complete their life cycles and will benefit from any reintroduction and expansion of their host fish populations. 


7. What are the risks of fish passage at Prairie du Sac Dam?

There are a number of risks that the Service will consider when evaluating the environmental consequences of providing fish passage.  Among these risks include the inadvertent passage of aquatic invasive species, such as Asian carp (Hypophthalmichthys spp.), and fish borne diseases of concern, like Viral Hemorrhagic Septicemia, to upstream areas.  Such introductions would result in adverse effects on upstream aquatic resources.


8. How much will building, operating, and maintaining a fishway cost?

We will analyze costs in more detail in the Environmental Assessment, but in general, the cost to build a fishway could range from just under a million to several million dollars, depending on the fishway design.  Operation and maintenance costs will also depend on the fishway design, but will likely be less than $100,000 annually.


9. Who will pay for the fishway?

Wisconsin Power and Light Co., owner and operator of the Prairie du Sac Dam, is responsible for complying with the conditions of a license the Federal Energy Regulatory Commission issued in 2002 that permits operation of the hydroelectric project at this dam.  A condition of the license, based on a prescription by the Department of the Interior, is construction, operation, and maintenance of a fishway.  The U.S. Fish and Wildlife Service supports development of renewable energy in environmentally responsible ways; provision of a fishway will help enhance environmental conditions for Wisconsin’s fishery resources that have been affected by the presence of the Prairie du Sac Dam.


10. Will my electric rates increase because of this project?

All electric rate increases in the State of Wisconsin need to be approved by the Public Service Commission of Wisconsin.  The U.S. Fish and Wildlife Service does not participate in decisions regarding electric rates and it is unknown at this time whether Wisconsin Power and Light Co. will attempt to recoup the cost of this project through a rate increase.


11. How can I learn more about this project?

Please visit the project’s website at www.fws.gov/midwest/GreenBay/PDSfishway.html for more information and any updates.



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Last updated: February 13, 2017