Automated detection and quantification of land reclamation in the Lower Chambal Valley (Madhya Pradesh, India): Using PlanetScope Imagery in Google Earth Engine

Abstract

The Chambal badlands in the Lower Chambal Valley in Madhya Pradesh, Central India, range among the largest badland zones in the world. In order to combat land loss and decline in agricultural productivity through badland formation, land levelling by local farmers as well as in governmental reclamation projects has become widespread. While this can help to increase agricultural area and productivity, there is evidence that it degrades soil quality and increases erosive processes. This study aims to identify and quantify land levelling in the Chambal badlands using the cloud-computing platform Google Earth Engine (GEE). The method is based on the GEE implementation of the time series analysis algorithm LandTrendr (Landsat-based Detection of Trends in Disturbance and Recovery). While originally developed to identify disturbances in forested regions, LandTrendr can be applied to various landscapes and land cover changes. Since land levelling patterns in the Chambal badlands occur at various spatial scales, the algorithm was adapted to process high-resolution PlanetScope data instead of the originally implemented medium-resolution Landsat data. Land levelling is accompanied by a removal of the badland vegetation cover of shrubs, trees, and occasional patches of moderately dense forest. Thus, annual time series of vegetation indices are used to detect newly levelled areas at pixel-level. The high temporal resolution of PlanetScope allows to calculate vegetation index values from cloud-free scenes from approximately the same date every year. The algorithm is tested in a small study area within the Chambal badlands; upon successful implementation it may be extended to the entire Chambal Valley. Thus, our LandTrendr implementation of PlanetScope Imagery in Google Earth Engine will allow to monitor future land levelling and agricultural reclamation activities in the unique geomorphological and ecological environment of the Chambal Badlands.