Evaluating an 80 Hz tonal noise from a hydropower plant

A pumped storage power plant produces significant noise such that adjacent areas were deemed uninhabitable for the local population. In recent years, the population in the area has increased, and the noise levels are now causing significant distress to the local population. The company operating the power plant and a citizens' initiative have both commissioned noise measurements. The measurements showed that the continuous pump noise was audible over many kilometers. The A-weighted sound-pressure level of 50 dBA at the next residential area underestimates the perceived noise, given the clear tonal nature in the low frequency range. Interviews of the exposed population, together with detailed "annoyance diaries" by a sample of the residents, proved their high level of annoyance. Their reported observations on distress and sleep disturbances coincide with the time course of the pumping operation. The pumping noise leads to annoyance in a large area, and to considerable nuisance in a smaller one. For the most exposed homes, long-term exposure might be considered a health hazard due to stress and disturbances in sleep quality. Therefore, the operator committed to developing a technical noise control plan. This case shows that a scientific approach within a complex environmental noise problem can foster an agreement about noise protection measures. However, this can only be successful if all involved parties participate in the process. Pilot studies are underway to test the impact of damping material layers on the pipes, the housing of the pipes, and the kind of air vessel solutions between the pumps and the pipes. Int J Occup Med Environ Health. 2019;32(3):401-11.