Monitoring and integrating the expansion of vegetated areas with the rate of groundwater use in arid regions

Abstract

<p>Frequent water table measurements are crucial for sustainable groundwater management in arid regions. These locations have developed a problem with excessive withdrawal throughout time. However, continuous readings are not available for the majority of these locations. Therefore, an approximate estimate of the rate of increase/decrease in water consumption over time may serve as a temporary substitute for the missing database. The goal is achieved by tracking the increase/decrease in vegetated areas that will generally correlate with changes in the rate of water use. The technique is based on two remote sensing data sets: Landsat7&8 from 2001 to 2021 and Sentinel2A from 2015 to 2021, as well as five vegetation indices: Normalized Difference Vegetation Index (NDVI), Renormalized Difference Vegetation Index (RDVI), Soil Adjusted Vegetation Index (SAVI), Enhanced Vegetation Index (EVI), and Transformed Vegetation Index (TVI). The datasets chosen provided the best performance for small-scale land farms at the research location. (Landsat7) data with a resolution of 30m revealed a substantial increase in land farms from 2.9km<sup>2</sup> in 2001 to 23.3km<sup>2</sup> in 2021. The use of the five indices with (Sentinel2A) allowed the classification of vegetated regions as heavy, moderate, or light, as well as the tracking of each class's increase from 2015 through 2021. Additionally, preliminary scenarios were built to measure the pace of growth in water use at the research site by evaluating the rise in vegetated areas and obtaining general information about crop types from farmers. Finally, the NDVI index was modified to better suit the arid areas. The new index is named Arid Vegetation Index or (AVI).</p>