Application of geographic information system and remote sensing in assessment of stream order and drainage pattern of selected watersheds in Akwa Ibom, Southern Nigeria

Abstract

A watershed, otherwise known as drainage basin, or river basin, or catchment area, is a territory from which many rivers and streams drain into a common reservoir such as a lake, a river or the ocean. Watershed morphometric parameters can be defined and computed using Geographic Information system (GIS) and Remote Sensing (RS). In this study, remote RS and GIS analysis techniques were used to delineate the boundary of the drainage basins under study.Three watersheds in Akwa Ibom state in Nigeria is being investigated here.At the moment, there is dearth of information or data on the morphometric parameters, their value ranges, and the significance of their application in watershed and management in the study area. For detailed study, Shuttle Radar Topographic Mission (SRTM) was used for delineating watershed boundary using SAGA GIS software. SRTM is a global research shuttle owned by the United States Geological Survey (USGS) that provides a geological, topographic and meteorological database for the Earth in a medium resolution digital format represented by digital elevation models (DEM). GIS Techniques has been used for assessing various morphometric characteristics of the drainage basin, as they provide a flexible environment and a powerful tool for the manipulation and analysis of spatial information. Mapping out the watershed for the study area and other morphometric parameters which are the three geopolitical zones of Akwa Ibom state, were estimated from Advance Space Technology Application Laboratory (ASTAL). The Digital Elevation Model (DEM) from the Shuttle Radar Topography Mission (SRTM) was also used. The findings reveal that the elongated shape of the basin is primarily influenced by thrusting and faulting. Also, lower-order streams dominated the basins, and the development of stream segments is influenced by rainfall.