Tracing of palaeochannels of Bakulahi river system in Uttar Pradesh, India

Abstract

Palaeochannels can be good possible reservoirs of groundwater and are good rechargeable aquifers. Bakulahi is a plain-fed tributary of the Sai River flowing from north-west to south-east direction with about 177-km length and about 841-km2 catchment area. It emanates from interconnected series of tals (large- to medium-sized shallow depressions) situated in the Raebareli district, Uttar Pradesh, India. Course of the Bakulahi River is shifted laterally and left many fluvial landforms—palaeochannels, oxbow lakes, meander cutoff, etc. The present study is based on the on-screen digitization of the Bakulahi River basin boundary, drainage network, palaeocourses, and other surface water bodies from high-resolution remote-sensing data (1 m × 1 m) available at Google Earth. The digitized details from remote sensing data are validated with some field observations. Different thematic maps are prepared by converting Google Earth feature files (.kmz/.kml) into GIS feature files (.shp) and importing layers into the GIS environment. There are about 115 palaeochannels covering about 137-km2 area (16.29%); about 6000 surface water bodies in forms of ponds/tanks having 23.36-km2 area (2.74%) and 40 oxbow lakes are mapped within the basin. This is the first scientific attempt to trace palaeocourses of the Bakulahi River. The present paper also answers the question about the origin of the Bakulahi River. Demarcation of precise basin boundary through manual method by using high-resolution remotesensing data is another contribution of this exercise which is otherwise a difficult task without the availability of high resolution DEM.