Google Earth Engine-Based Hypsometric Evaluation and Statistical Moments Analysis of Large River Basins

Hypsometric analysis of a river basin involves the evaluation of its relative area versus relative elevation relationship, and it enables an understanding of the area-wise spatial distribution of elevation. However, conducting hypsometric analysis for a large river basin presents limitations in terms of analysis as well as computational time and effort. Thus, this study presents an improved methodology for conducting hypsometric analysis and statistical moments evaluation of large river basins like the Ganga using an ensemble of Google Earth Engine (GEE) and the CalHypso tool. The Ganga River Basin (GRB) extends from the Himalayas to the Bay of Bengal and is characterized by significant geological and geomorphological diversity. Being a relatively young mountain range makes this region especially prone to active erosional processes like landslides and seismic activities. Thus, in this study, hypsometric analysis was conducted on 15 sub-basins of the GRB, revealing variations in geomorphic stages ranging from young (actively undergoing erosion) to old (relatively stable). The study further categorized the sub-basins into different geological stages based on hypsometric integral (HI) values. The majority of GRB sub-basins were classified as old. Sub-basin-wise statistical moments of hypsometric skewness (HSK), hypsometric kurtosis (HKU), density skewness (DSK), and density kurtosis (DKU) were also evaluated to understand the erosion dynamics at different courses of the basin. The results highlighted significant spatial variations, with northern sub-basins exhibiting higher erosion rates and more peaked hypsometric curves (HCs), which are indicative of advanced geomorphic development. Thus, the study’s findings underscore the utility of integrating GEE for large-scale river basin analysis and offer valuable insights for resource management in regions vulnerable to erosion. This methodology provides a robust framework for understanding the complex erosional and developmental processes in large river basins and can be readily used by researchers and policymakers to gain further insights.