Impact of topography on attenuation of noise from a cement plant in a hilly terrain

The influence of hill topography on noise from industrial plants is scantly documented, despite the fact that the noise profiles can vary in plains and in hilly terrain. Significant noise data from a cement plant flanked by hills were collected and analyzed for its attenuation over space in the direction of the valley and across the hills. It was observed that the noise attenuation is not similar to that experienced in plains owing to interactions with the mountains. The overall effect has been modelled over different distances between the four sources of the noise and several monitoring stations. The analyzed noise data showed that the influence of the major source of noise is obvious, yet difficult to differentiate. An iterated weighted distance from the noise sources, proved to be a better estimate for distance while modelling the attenuation of the noise. A relationship between the equivalent noise levels during the day and night could also be established. The effect of relative altitude and slope could be modelled using nonlinear multivariate analysis and the response surfaces were obtained for minimum, maximum and average values of the variables. Noise shadow zones could be identified with noise contouring which reflects reduction in the noise levels on hind side of the hills. The impact of topography and possible interference could thus be defined in such hilly terrain. The information can be used to define the noise mitigation strategies for adjacent habitats and mitigation of human response. The findings of the paper can also be used by prospective plants in hilly areas. [Display omitted] •The impact of topography on noise from industrial plants is scantly documented.•Noise data for 5 days was acquired from a cement plant located in a small valley in a hilly terrain.•Summarized Leq data was analysed for noise attenuation with iterated distance from noise sources and yielded the best possible R2.•Attenuation characteristics of noise in such terrain could be characterized by a response surface model, delineating the interaction of noise through a distance and topography.•The study can be used to understand the behaviour of industrial noise in hilly terrain and utilized by such planned plants to devise their noise mitigation strategies.