Blocking bighead, silver, and other invasive carp by optimizing lock and dams

Project manager: Peter Sorensen

Funded by: Environment and Natural Resources Trust Fund as recommended by the Legislative-Citizen Commission on Minnesota Resources

Project description: Untold numbers of invasive Silver and Bighead carp presently inhabit the Mississippi River below the Iowa border from where they threaten to invade Minnesota. This project proposes to solve this problem by developing a scheme to modify lock and dam structures in Minnesota by enhancing their deterrent properties through four key, linked steps.

Activity 1: Install a safe carp deterrent in front of the lock at Lock and Dam #8 located at the Iowa border while guiding efforts to enhance and optimize velocity fields to stop carp movement through its gates while having minimal effects on native fishes. The goal of this activity is to immediately and safely maximize water velocity through the gates of lock and dam #8 near the Iowa border while deploying a simple and safe acoustical deterrent system in its lock chamber as a stop-gap measure.

Activity 2: Quantify the swimming capabilities of both species of adult Bighead carps, thereby producing the data needed to optimize dam function. Swimming performance data for adult carps are essential to accurately forecast passage and optimize gate function so that velocities are not higher than needed.

Activity 3: Test and develop new acoustical deterrent systems that best deter carp from entering lock chambers which have minimal effects on native fishes. Lock chambers present a potential way for Bigheaded carps to pass upstream, irrespective of gate function. Sound deterrents have special promise because carps are hearing specialists.

Activity 4: Develop numeric solutions to eventually optimize dam operation at all Minnesota lock and dams (#2 through #8) to prevent Bighead carp invasion statewide while having minimal effects on native fishes. The purpose of this activity is to identify potential weaknesses (scenarios by which carp might swim thorough the lock and dams) in Lock and Dam #2 in Hastings and then optimize gate operation to block Bighead carp throughout the entire lock and dam system in Minnesota. Lock and Dam #2 is of special interest because it maintains higher velocities than other dams, is ideally situated far from the invasion front, and is located downstream of the Minnesota River.

Activity 5: In order to test and validate the models previously developed, researchers have radio-tagged invasive common carp (as a surrogate to Asian carp) as well as 250 native fish specimens. They will monitor the tendency and ability of these fish to challenge the increased flow from the dams as well as how they move through or around the dam. This work will occur at Lock and Dam #2.

Activity 6: Researchers will also use high-resolution imaging sonar to capture the location of all fish in the lock area when the acoustical deterrent system is turned on and off, which will show whether and how their behavior is affected by the sound. This work will occur at Lock and Dam #8 and will improve and facilitate implementation of deterrent apparatuses at lock and dam structures on the Mississippi River.

Activity 7: In order to test upstream-migrating silver and bighead carp (instead of common carp), researchers will design and help install an underwater speaker system on the lock gates at Lock and Dam #19 in Iowa.

Activity 8: Develop solutions to address weaknesses in Lock and Dam #4 and optimize its gate operation to prevent passage of invasive carp. This lock and dam system maintains a high velocity than other dams, is situated far from the invasion front, and is located just upstream of Lock & Dam #5, so the two systems can be used in conjunction. The project will include developing a 3D statistical model to calculate water velocities in and around the dam under a variety of conditions; measuring velocities near the dam to validate the model; developing and implementing a computation tool to search through the 3D velocity fields to identify specific swimming pathways that carp could take; and pairing this information with already-known swimming performance data to determine how best to block carp passage while having minimal effect on native fishes.

The final objective of this work is to make explicit recommendations with (and to) the USACE for optimization of all Minnesota lock and dams (#2 through #8) to block the invasion of Bigheaded carps while still serving USACE needs and having minimal effects in native fishes.

Project start date: 2014

Project end date: 2018


We successfully collaborated with the United States Army Corps of Engineers (USACE) and developed new ways and technologies to impede the upstream movement of invasive (bigheaded) carp through their locks and dams in the Mississippi River. Further, these approaches have now been implemented at Lock and Dam #8, which is the southernmost Lock and Dam in Minnesota and has thus been our focus. At this structure, dam spillway gate operating protocols were adjusted by the USACE to optimize their ability to stop carp and speakers added to the lock gates to deter carp with few effects on native fish. This is the first structure in the world to be so modified and our calculations suggest it now stops twice as many carp as it once did (well over 90%). Tentative plans for similar modifications to Lock and Dams #2 and #5 (the other most promising structures in Minnesota) have also been presented to the USACE for future deployment at their discretion. This progress was possible because we met all four objectives of this project: 1) we added speakers to Lock and Dam #1; 2) we quantified and published how well bigheaded carp swim (and thus what flows might stop them); 3) we developed and tested several new acoustic systems in the laboratory and field that stop carp but do not affect native fish; and 4) we developed new solutions for the gates at Lock and Dam #2-8 and provided specific data (specific solutions) for  Locks and Dams #5 and #2, the most promising structures of these.

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