Prototype development of underwater noise impact alert region prediction system

Abstract

Offshore wind farms are the main project in western Taiwan. Since the underwater noise generated by piling poses a threat to the marine mammals, the issue of detrimental impact of noise on Sousa Chinensis is proposed. To avoid causing behavioral disturbance and injury from pile driving noise, Underwater Noise Impact Alert Region Prediction System (UNIARPS) was established to estimate the acoustic field at any depth and distance from piling source. The system can be illustrated as four components, environment databases, acoustic propagation model, source modeling, and noise level prediction. The ocean numerical model (TCONFS) generates time spatial dependent temperature profiles for water column variability, and geo-acoustic and bathymetry databases are imported as environmental inputs. Adiabatic mode theory is used to simulate the piling noise propagating in shallow water and the impulsive noise emanating from source is evaluated via finite element method. While the auditory threshold of cetacean set as criterion level, the system can demonstrate the modeling outputs and predict noise impact region, and these results are useful to prior planning on how to station the guarding boats in preventing dolphins entering the noise impact region. [The financial support provided by Bureau of Energy (Grant No.102-D0105) is gratefully acknowledged.]