The U.S. Fish and Wildlife Service are currently developing an environmental assessment to evaluate the environmental impacts of providing a way for fish to pass upriver and downriver from the dam at Prairie du Sac, Wisconsin. Wisconsin Power and Light, which owns and operates the dam, is required to provide a fish passage at the dam which is required under its license requirements granted by the Federal Energy Regulatory Commission. The Wildlife Service must develop this assessment to follow the National Environmental Policy Act which must show the impact of providing this “passageway” for fish to move upriver and downriver from the local dam. The main problem that has been encountered is how to prevent the upstream travel of non-native invasive fish species like the Asian and silver carp which can destroy a fishery in a short period of time.
The dam at Prairie du Sac is the first barrier on the Wisconsin River some 92 miles from the confluence with the Mississippi River. The Prairie Dam is a complete barrier to any fish movement up or down the river. The Prairie du Sac Dam was built in 1915 and historically there were 19 fish species and 15 kinds of freshwater mussels upstream from the dam or presumed to be there based upon the available habitat and range estimates. But, since the dam’s construction, none of these aquatic species are still found in the Wisconsin River between the Prairie du Sac Dam and the Kilbourn Dam at Wisconsin Dells. The Kilbourn Dam is the next dam on the river system above the Prairie Dam.
The dam at Prairie du Sac is a complete barrier to any fish movement upstream. The U.S. Fish and Wildlife Service say that it is necessary to find someway which would allow fish to bypass or get by the Prairie du Sac Dam. One way to accomplish this goal would be the creation of a fishway. Some fish species, like the paddlefish and lake sturgeon, need this upstream access seasonally to complete their life cycles. A fishway is an engineered structure that allows the passage of fish around the dam. The fishway, according to the U.S.F.W.S. must be constructed to allow for the safe, timely, and effective movement of fish up and downriver from the dam. This “fishway” would be a compromise between power production and the necessity of getting the fish to their upriver habitat and spawning areas.
The dam at Prairie du Sac is owned and operated by Wisconsin Power and Light Company, which is a subsidiary of the Alliant Energy Corporation. The owners of hydroelectric dams are required by law to obtain an operating license from the Federal Energy Regulatory Commission. This operating license is necessary because under the Federal Power Act money is made by a private company through the use of a public waterway which happens to be the Wisconsin River.
Numerous agencies including the Wisconsin DNR, USFWS, and the River Alliance made formal recommendations during the Federal Energy hydropower licensing that a fish passage be constructed at the Prairie du Sac Dam to allow the passage of migrating fish to habitat above and below the dam. The Federal Energy Regulatory Commission changed the Prairie license to provide a safe and timely passage of fish.
Goals have been established for the Prairie du Sac Dam fish passage and they are; 1) Re-establish the fish populations of the blue sucker, paddlefish, shovelnose sturgeon, and any other native fish species above the dam and allow access and seasonal migration to these locations. Two of the spawning areas are near the Wisconsin Dells and Baraboo River spawning areas. 2) Re-connect the native fish species and native mussels above and below the Prairie Dam allowing the migration to spawning and seasonal habitats. 3) Alliant Energy must also follow and comply with all laws and regulations, including all state and federal permit and license regulations.
Fish Passage Alternatives
· The fish passage must provide safe passage for the fish passing through the dam with no injuries or death to fish.
· There must be a “timely” passage during the appropriate seasons or periods of the year when fish are attempting to pass the dam. Fish must be allowed to complete their life cycles which at times is within a short environmental window.
· The passage must also allow passage of native fish (walleye, sauger) that want to move upriver or downriver of the Prairie Dam, but not permit fish which are invasive from moving upriver of the dam.
· Have in place reasonable precautions and barriers to prevent the upriver movement of invasive species like the Asian carp and silver carp.
The Asian and silver carp began working their way up the Mississippi River and its tributaries since the 1970’s from fish farms in the South. I’ve been to the Illinois River about 175 miles south of the Madison area where the silver carp are so numerous that people have to wear helmets and nets to protect themselves from the silver carp that are known for jumping out of the water by the noise of an outboard motor. Asian and bighead carp have moved up the Mississippi River and into the Wisconsin River too. The invasive fish have also moved up the Chicago Sanitary Canal where a barrier has kept them out of Lake Michigan and the Great Lakes. But, this is not much protection for the many million dollar fishing industry of the Great Lakes.
Currently, numerous agencies are looking at different types of fishways or passages like; the trap and transport fishway, the pool-type fishway, the lock fishway, the rock ramp fishway, the nature-like fishway, and the Denil (developed in 1909 by a Belgian scientist, G. Dentil) Fishway.
The trap and transport fishway may be the best way to keep out and prevent the spread of the invasive fish. This fishway is called a fish elevator or “fish lift” which consists of an entrance channel that pushes fish, through by attraction flows, to a hopper that acts as a trap where the fish can be sorted and inspected by biologists and fishery personnel. Most of the other fishways are not suited or capable of preventing invasive species fish from moving upriver. The lock fishway is another possibility, but I’m not sure if there is a way to sort and inspect the fish that are to be moved upriver. As with most if not all of these fish passges, there is no effective way to control the invasives. The only thing that now can be done is to prevent their further spread into new waters.
The public meeting that was held in Prairie du Sac on July 15th was very well attended and the federal and state officials present did a good job in explaining the situation faced at the Prairie du Sac Dam and the Wisconsin River. We are faced with a problem of preventing any upriver movement of these invasive fish while complying with state and federal laws. The selected passageway for fish must prevent downriver fish from accidently jumping or swimming upriver from the dam. There must be a “default closed position” where the fish would have to be manually transferred upriver by trained personnel on site and manually operating the fishway. All fish transferred upriver must be sorted, inspected, and handled by DNR or Federal trained personnel. All fish transferred upriver must have DNR permits before the upriver transfer past the Prairie du Sac Dam.
I hope that everyone reads and becomes informed by this very serious problem that we are now facing in our local waters and the Great Lakes. These invasive fish are plankton feeders that disrupt food chains and can outcompete native fish for food. Remember, that there is no effective control method for Asian carp and all that we are hoping for is to prevent the further spread of these invasive fish.