How do Invasive Species Get in Our Waterways? AIS Pathway Spotlight: Canals, Dams, and Diversions

Canals, Dams, and Diversions: Balancing Connecting Waterways and Consequences

Transport pathways are the means by which AIS have been introduced to and spread across Wisconsin. The number of pathways have continued to grow as new technologies allow for faster movement of goods and services than ever before in history. Every month, we will be putting a spotlight on the different pathways aquatic invasive species can reach new waterways. We start out this monthly series with a focus on the first pathway; Canals, Dams, and Diversions.

Canals and diversions have a long history associated with facilitating AIS dispersal as they connect previously separated waterways. These man made waterways can be used to move goods and people from place to place. Historically, taking boats between the Great Lakes took considerably less time than other available means of transportation. Some canals are built that connect previously separated lakes (ex. The Welland Canal) while others are constructed to make navigation easier on natural waterways. In cases where waterways are connected that were previous separated, species have access to new lakes that were previously unreachable.

On the opposite side of the spectrum, structures such as dams and culverts can act as barriers to species between waterbodies. Species are then limited in their distribution either by possibly being unable to move upstream (culvert) or very unlikely to bypass a structure (dam).

In the Winnebago System, efforts to prevent the spread of AIS through this pathway while allowing for safe recreational use have been ongoing for decades. Balancing human use/needs and limiting human impacts to our waterways is a central theme to this AIS pathway.

Case Study: Fox River and the Winnebago System

There is a difference in elevation of 168 feet between Lake Winnebago and Lake Michigan. Dams and locks on the Fox River were designed and constructed in the 1800s to move commerce along the river. Prior to dam and lock construction, vessels needed to portage around the rapids along the Fox River. As newer technologies, such as the railroad, were constructed across the Western United States, traffic using the lock system decreased and some of the locks fell into disrepair. By the 1980s, the U.S. Army Corps of Engineers was in charge of the Fox Locks and recommended the locks system be dismantled in the early 1980s due to decreased traffic. In 2001, the Fox River Navigational System Authority (FRNSA) was created by the Wisconsin state legislature. The authority overseeing the locks system was transferred to FRNSA in 2004. FRNSA worked to restore the Fox Locks system with all but one lock restored starting in 2005 and finishing in 2015.

Overtime, several locks have been closed to help stop the spread of AIS. In 1988, the Rapid Croche lock was closed to stop the spread of sea lamprey and other AIS from Lake Michigan into Lake Winnebago. A sea lamprey barrier was also installed and FRNSA is required to maintain the barrier under Wisconsin Statute Chapter 237.10(1). FRNSA is currently exploring effective ways of opening navigation while preventing the spread of aquatic invasive species. If plans include the Rapide Croche lock, then according to Wisconsin Statute Chapter 237.10(2), ). “If the authority decides to construct a means to transport watercraft around the Rapide Croche lock, the authority shall develop a plan for the construction that includes steps to be taken to control sea lampreys and other aquatic nuisance species. The authority shall submit the plan to the department of natural resources and may not implement the plan unless it has been approved by the department.” No sea lampreys have ever been found in the Winnebago System. In 2015, round gobies were found in Little Lake Butte des Morts. An extensive sampling effort by the WDNR found that a round goby population had become established in Little Lake Butte des Morts. In order to protect the Winnebago System, FRNSA worked with the WDNR to close the Menasha Lock. No round gobies have been found in Lake Winnebago, Poygan, Winneconne, or Butte des Morts. Sampling efforts in 2015 in the lower Fox River north of Little Lake Butte des Morts did not found round gobies. The WDNR believes that the round goby population found in Little Lake Butte des Morts was likely introduced through an angler(s) who was using round gobies as bait. In 2018, the WDNR started to receive goby reports from anglers in the Lower Fox (i.e. Appleton down to Kaukauna). This downstream dispersal pattern supports the hypothesis that gobies were introduced into Little Lake Butte des Morts and then have begun to move back downstream.

All text from this article is from the Winnebago Waterways AIS Strategic Plan. Sources can be found in the AIS Strategic Plan document. For more information on what the state of Wisconsin is doing to prevent the spread of AIS, check out the Wisconsin AIS Management Plan.