DNR outlines Lock and Dam 5 plan to deter invasive carp with underwater acoustic system and trap-and-sort option

Minnesota Department of Natural Resources project coordinator Carly Wagner told the Outdoor Heritage Council that the Lock and Dam 5 invasive‑carp project will combine a selective underwater acoustic deterrent, targeted removal and expanded monitoring to slow upstream spread of bighead and silver carp. "This project incorporates deterrence, removal and monitoring to develop an integrated system for invasive carp at Lock and Dam 5," Wagner said.

The council heard that DNR selected an underwater acoustic deterrent system (UADS) for design after a comparative assessment. USACE Saint Paul District is leading engineering design, with technical support from USGS and other federal partners. Wagner said the design team has completed 35% design and is working toward 65%; permitting work is expected to begin later this summer and 95% design will inform construction estimates and final schedule.

Why it matters: Lock and Dam 5 sits upstream of Winona on the Mississippi River and is a key point where slowing passage could reduce the chance of invasive carp establishing reproducing populations in Minnesota waters. DNR emphasized the deterrent is one component of an integrated approach that also includes removal and adaptive monitoring.

Project scope and schedule: DNR presented the UADS (sound‑based) approach as the preferred option because it demonstrated comparable effectiveness to bioacoustic fish fence experiments while presenting lower extrapolated costs. The team expects to complete deterrent design by February 2027 under the council‑supported extension of the design deadline to 6/30/2027. DNR anticipates construction during the winter navigation closure (winter 2027–28) and said appropriation authority for the project extends to 2029.

Costs and operations: Project speakers offered extrapolated cost benchmarks rather than final estimates. Based on installations at Lock 19, DNR presented a rough capital estimate of about $3.5 million for a Lock 5 UADS (extrapolated) and annual operations and maintenance near $86,000, with a larger five‑year maintenance event estimated at roughly $581,000. A trap‑and‑sort removal system (whoosh/automated sorting) was discussed as an add‑on with a benchmark capital price near $4 million and potential annual O&M in the range of $61,000 per available studies; DNR said the trap‑and‑sort would be pursued after the deterrent cost and remaining appropriation are better understood.

Efficacy and limitations: DNR and partner researchers said field tests at other locks show deterrents reduced invasive carp lock‑passage by roughly 50% with limited impacts on many native species in monitored trials. They cautioned that technologies currently deter lock‑channel passage but do not yet prevent dam‑gate passage under open‑river or high‑water conditions; USGS monitoring shows that during some flood years fish moved upstream through dam gates.

Questions from council members focused on long‑term funding for operations and maintenance, how the deterrent performs in flood years, disposal or use of removed carp, navigation and acoustic impacts on boats, and contingencies if permitting or construction takes longer than expected. DNR and federal partners said they are coordinating with USACE on real‑estate and safety/permitting questions, continuing acoustic air‑sampling and boat‑based trials at Lock 19, and tracking telemetry data to identify where fish cross the structure.

What’s next: DNR will continue 65% and 95% design, begin permitting later this summer, and provide cost and permitting updates to the council as 95% plans become available. Council members asked staff to track operations‑funding options and to consider removal‑disposition plans for harvested carp.

Source: Presentation and multi‑agency Q&A with Minnesota DNR, USACE, USGS and US Fish and Wildlife Service (DNR project coordinator Carly Wagner and partner researchers).