White-Nose Syndrome and increased disturbance of habitats used by bats for roosting and foraging has led to a growing concern about the U.S. bat population over the last decade. Bridge repair and replacement projects are required to follow additional regulatory requirements to avoid and minimize impacts to bats; when protected bat species are present on bridges. Some of these requirements (e.g.; timing restrictions) are challenging to implement given Minnesota's short construction season. The objective of this project was to evaluate the feasibility and efficacy of deploying non-lethal ultrasonic acoustic devices in the field to temporarily deter bats from roosting on bridges ahead of construction or maintenance activities; while minimizing harm to bats and non-target species. The technology was evaluated at two test sites in Minnesota; one short-term and one long-term; during the summer of 2019. Considering the findings from both the acoustic monitoring data and the field inspections; acoustic deterrents appeared to effectively work to temporarily deter bats from select abutments. This report presents the field study design; findings from the field implementation; research benefits; and implementation steps for the Minnesota Department of Transportation (MnDOT).
The objectives of this research were twofold. The first objective was to identify the needs for the inspection methodology, manuals, training, and the timetable needed for all bridge owners to start collecting elementlevel bridge inspection data. The second objective was to identify how to incorporate this new inspection methodology into the rich reporting tools and performance measures that the Minnesota Department of Transportation (MnDOT) uses for determining the bridge projects in the annual program. Working with the MnDOT Bridge Office, the research team identified the necessary changes to the bridge inspection elements that would both ensure MnDOT conforms to the new American Association of State Highway and Transportation Officials (AASHTO) Guide Manual for Bridge Element Inspection and provide the necessary data for the agencys bridge management process. The changes needed for MnDOTs Bridge Replacement and Improvement Management (BRIM) were also identified working with the MnDOT Bridge Office.
