Quantitative assessment of the drainage morphometric characteristics of Chaohu Lake Basin from SRTM DEM Data: a GIS-based approach

Abstract

ABSTRACT This study is focused on the morphometric evaluation of some hydrological parameters of the streams/rivers in Chaohu Lake Basin and its influence on land-use changes in the basin. The hydrological parameters considered here include drainage network, linear morphometric, areal, and relief parameters as well as the focal statistics of the stream variables in the Chaohu Lake catchment. Morphometric analyses and assessments of the basin were carried out (in ESRI©ArcGIS 10.6.3) utilizing the remotely sensed georeferenced Digital Elevation Model (DEM) data obtained from Shuttle Radar Topographic Mission (SRTM) while the land-use change analyses (executed in ESRI© ArcGIS) was based on Maximum Likelihood supervised Classification (MLC) of subsets of Landsat MSS and OLI/TIRS images acquired in 1979 and 2015. Linear morphometric results from the analyses include river and stream length (18.22 km), stream order (1–4), mean stream length (0.01 km), bifurcation ratio (2.11–4.34) and mean bifurcation ration (2.15) respectively. The areal morphometric attributes extracted include drainage density (670.85 km2), basin perimeter (789.3 km), basin area (13,350 km2), Circularity ratio (Rc, 0.0059) and relief aspects with the highest value at 1.282 m and the lowest elevation at −7 m. The drainage system here is designated as the fourth-order stream of a majorly dendritic pattern which may be a result of the structural and geomorphological influence on the stream system. In this study, the analyses and understanding of the dynamics of the different streams in the basin are shown to indicate the easy accessibility to the abundant freshwater systems in the basin which has contributed to the changes in land-use patterns over the last five decades in the basin. The notable changes include the increase of agricultural lands from 29.8% in 1979 to 45.2% in 2015; and the built-up (urban) areas from 3.5% in 1979 to 25.1% in 2015, respectively.