Automated image analysis for experimental investigations of salt water intrusion in coastal aquifers

Abstract

A novel methodology has been developed to quantify important saltwater intrusion parameters in a 11 sandbox experiment using image analysis. Existing methods found in the literature are based mainly 12 on visual observations, which are subjective, labour intensive and limit the temporal and spatial 13 resolutions that can be analysed. A robust error analysis was undertaken to determine the optimum 14 methodology to convert image light intensity to concentration. Results showed that defining a 15 relationship on a pixel-wise basis provided the most accurate image to concentration conversion and 16 allowed quantification of the width of the mixing zone between saltwater and freshwater. A high 17 image sample rate was used to investigate the transient dynamics of saltwater intrusion, which 18 rendered analysis by visual observation unsuitable. This paper presents the methodologies developed 19 to minimise human input and promote autonomy, provide high resolution image to concentration 20 conversion, and allow the quantification of intrusion parameters under transient conditions.