Evaluation of Salinity Intrusion in Arable Lands of Al-Batinah Coastal Belt Using Unmanned Aerial Vehicle (UAV) Color Imagery

Abstract

Salinity by seawater intrusion due to excess groundwater pumping for irrigation is a major environmental challenge in the coastal areas of Oman. Increasing salinity levels moving inward the arable lands is happening in a rapid manner. Thus, salinity needs to be evaluated and quantified using a fast and accurate method. The objective of this study is to estimate salinity intrusion in Al-Batinah coastal belt using color aerial imaging. The study was conducted in five randomly selected sites with increasingly different distances from the seashore of Al-Suwaiq area in Al-Batinah region. Color aerial images were acquired for each site by an Unmanned Aerial Vehicle (UAV). Images were enhanced by orthorectification in ENVI software. Green Leaf Index (GLI) was obtained from each site image using Matlab software. Image analysis results were compared with the results of analyzed soil and water samples taken for ground-truth verification. There was a strong negative correlation between the distance from the seashore and the soil EC of each site (R = -0.95). Similarly, the mean value of GLI increased as the salinity levels decreased, R= -0.96 and -0.92 for soil EC and water EC, respectively. The findings of this research work demonstrated the possibility of accurately use of color images taken by a UAV to quantify the salinity effect on vegetation along the costal belt.