Semi-automatic delineation of badlands using contrast in vegetation activity: a case study in the lower Chambal valley, India

Abstract

Population growth worldwide leads to an increasing pressure on the land. Recent studies reported that many areas covered by badlands are decreasing because parts of badlands are being levelled and converted into arable land. It is important to monitor these changes for environmental planning. This paper proposes a remote-sensing based detection method which allows mapping of badland dynamics based on seasonal vegetation changes in the lower Chambal valley, India. Supervised classification was applied on three Landsat (Thematic Mapper) images, from 3 different seasons; January (winter), April (summer) and October (post-monsoon). Different band selection methods were applied to get the best classification. Validation was done by ground referencing and a GeoEye-1 satellite image. The image from January performed best with overall accuracy of 87% and 0.69 of kappa. This method opens the possibilities of using semi-automatic classification for the Chambal badlands which is so far mapped with manual interpretations only.

Geomorphological evolution of badlands based on the dynamics of palaeo-channels and their implications

“…In the process of headward erosion, there can be number of processes involved including widening, branching of gullies, undercutting and plunge pools, etc. As shown by Ranga et al (2015), vegetation activity varies over the year which may also influence erosion processes. During major part of the year, erosion activities are not so destructive but on the onset of monsoon huge soil losses could be seen.…”

“…Steep scarps form the boundary between badlands and the adjacent inactive flood plains. At many places, levelling activities on such scarps were recorded, therefore, on such areas boundary becomes vague and land use becomes transitory (Ranga et al 2015). The active flood plain is restricted to the narrow incised valley, marked by point bars on the concave curves of meanders (figure 2d), which are formed by meander cut-off and lateral migration of the river.…”

“…The average annual rainfall is ca. 800 mm (Ranga et al 2015), more than 85% of which is received in the monsoon season (Tandon et al 2006). The UCV and MCV are covered mainly with the rocky terrain; only the lower reaches flows on the alluvium, deposited by the Chambal River itself.…”

“…On-desk interpretation was carried out on a number of satellite images from different sensors including Landsat mosaics (spatial resolution = 30 m) (http://earthexplorer.usgs.gov/) from Thematic Mapper sensor, images from LISS-III sensor (spatial resolution = 23.5 m) from Indian remote sensing satellites, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) (spatial resolution = 15 m), GeoEye image (spatial resolution = 0.5 m), images from CORONA missions (Galiatsatos 2004) (spatial resolution = 1.8 m (Sohn et al 2004)) from the cold-war period (for more details on GeoEye & CORONA image, see Ranga et al 2015) and Shuttle Radar Topographic Mission (SRTM) digital elevation model (spatial resolution = 90 m).…”

Dynamics and patterns of land levelling for agricultural reclamation of erosional badlands in Chambal Valley (Madhya Pradesh, India)

“…Newly levelled land is either still bare or sown with sparse crops of mustard, millet or lentils that do not exhibit high percentage cover; its spectral reflectance is much higher due to the light colours of the sandy-loamy alluvial sediments. They also found, however, that a clear spectral separability of badland and levelled land is hampered by the various degrees and phenological stages of vegetation cover in both, and that levelled land as a transitory class between badland and cropland is difficult to grasp with automated classification procedures (Ranga et al, 2015b). Ranga et al (2015b), who investigated normalized difference vegetation index (NDVI) time series for the Chambal Valley badlands, found a maximum difference of badlands and levelled land during January-February (peak of rabi cropping season) and September-October (harvesting in kharif cropping season and monsoonal vegetation peak in badland shrubland).…”