Name: Mark Bevelhimer
Address: Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6351, USA
Underwater noise associated with the installation and operation of hydrokinetic turbines in rivers and tidal zones presents a potential environmental concern for fish and marine mammals. Comparing the spectral quality of sounds emitted by hydrokinetic turbines to natural and other anthropogenic sound sources is an initial step at understanding potential environmental impacts. Underwater recordings were obtained from passing vessels and natural underwater sound sources in static and flowing waters. Static water measurements were taken in a lake with minimal background noise. Flowing water measurements were taken at a previously proposed deployment site for hydrokinetic turbines on the Mississippi River, where sounds created by flowing water are part of all measurements, both natural ambient and anthropogenic sources. Vessel sizes ranged from a small fishing boat with 60 hp outboard motor to an 18-unit barge train being pushed upstream by tugboat. As expected, large vessels with large engines created the highest sound levels, which were, on average, 40 dB greater than the sound created by an operating hydrokinetic turbine. A comparison of sound levels from the same sources at different distances using both spherical and cylindrical sound attenuation functions suggests that spherical model results more closely approximate observed sound attenuation.
This research was supported by the United States Department of Energy’s (DOE) Office of Energy Efficiency and Renewable Energy, Water Power Program.
Ft Loudoun Lake, TN; Mississippi River, near Memphis, TN; Cobscook Bay, ME
- To compare noise produced by hydrokinetic turbines to other natural and anthropogenic sources of noise
- To evaluate a cylindrical spreading model and a spherical spreading model for sound extrapolation in the context of tidal and large river deployment sites
The results of this study suggest that the sounds produced by a single bottom-mounted HK turbine is significantly less than most of the other anthropogenic noise sources in rivers and bays. The predicted sound right at the TidGen turbine is either about the same as or only slightly louder (depending on which attenuation model is used) than the natural background noise in high velocity water. At a distance of 20 m the TidGen turbine is probably not even within the hearing range of most fish. It is unlikely that a single turbine will have any meaningful effect on the normal behavior of fish in the general area. The cumulative effect of tens or hundreds of turbines in an array on the other hand would produce sound over a larger area and with a greater cumulative sound.
Bevelhimer, M.; Deng, D.; Scherelis, C. (2016). Characterizing Large River Sounds: Providing Context for Understanding the Environmental Effects of Noise Produced by Hydrokinetic Turbines. Journal of the Acoustical Society of America, 139(1), 85-92. https://tethys.pnnl.gov/publications/characterizing-large-river-sounds-providing-context-understanding-environmental-effects