An integrated assessment of the impact of precipitation and groundwater on vegetation growth in arid and semiarid areas

TL;DR

This study presents an integrated framework combining remote sensing, water flow modeling, and field data to assess how precipitation and groundwater influence vegetation growth in arid regions, highlighting groundwater's critical role during droughts.

Contribution

It introduces a novel combined approach using remote sensing and water modeling to analyze water-vegetation interactions in arid environments.

Findings

Strong correlation between groundwater depth and NDVI during droughts

Groundwater significantly supports vegetation growth in arid areas

Decreasing groundwater levels threaten vegetation survival during droughts

Abstract

Increased demand for water resources together with the influence of climate change has degraded water conditions which support vegetation in many parts of the world, especially in arid and semiarid areas. This study develops an integrated framework to assess the impact of precipitation and groundwater on vegetation growth in the Xiliao River Plain of northern China. The integrated framework systematically combines remote sensing technology with water flow modeling in the vadose zone and field data analysis. The vegetation growth is quantitatively evaluated with the remote sensing data by the Normalized Difference Vegetation Index (NDVI) and the simulated plant water uptake rates. The correlations among precipitation, groundwater depth and NDVI are investigated by using Pearson correlation equations. The results provide insights for understanding interactions between precipitation and groundwater and their contributions to vegetation growth. Strong correlations between groundwater depth, plant water uptake and NDVI are found in parts of the study area during a ten-year drought period. The numerical modeling results indicate that there is an increased correlation between the groundwater depth and vegetation growth and that groundwater significantly contributes to sustaining effective soil moisture for vegetation growth during the long drought period. Therefore, a decreasing groundwater table might pose a great threat to the survival of vegetation during a long drought period.