Developing a natural acoustic barrier for urban areas

Abstract

Increasing noise pollution has severally effected the urban areas where noise generated by traffic is considered as the major noise polluter. As a solution to the noise problem using noise barriers is an approach proven to be effective but due to land scarcity and social needs in urban areas applying noise barrier solution is challenging. Using a natural barrier as a noise barrier is a promising approach. Natural barriers are large or small closely grown tree belts, vegetation walls, natural stone structures, tree fences etc. Natural barriers, have emerged as the new trend to address problems in urban areas and has developed into vertical gardening, green roofs and hybrid natural barriers presently. The use of natural barriers as a solution is highly dependent on the human perception. The research was carried out to identify the human perception and human acceptance of natural barriers in Sri Lankan context and find out the level of acoustic disturbance people are facing. Focusing urban and suburb areas a quantitative approach was adopted via a questionnaire survey and actual sound measurements were taken in the western province of Sri Lanka. Secondly field testing was carried out to evaluate the performance of existing natural barriers to identify their acoustic performance. Closely grown tree belts which assumes a cuboid shape were used as test barriers. Multiple Linear Regression (MLR) models Artificial Neural Network (ANN) models were used to evaluate the performance of natural barriers. Cuboid shape natural barrier with 85% of green cover or more and overall height closer to 2 meters or more has proven to be an effective acoustic barrier for urban areas.