The Detection of Flow Directions of Surface Waters using ArcMap

Water management in agricultural areas requires knowledge of flow directions as well as lost water recuperation areas. The Inner Delta of Niger threatened by desertification, despite its great agricultural potential, loses an enormous quantity of runoff water every year. In this paper, the study focuses on the detection of flow directions and areas susceptible to be flooded. For this purpose, two new approaches have been applied, namely “geometrical interval and profile interpolation” to identify flow directions and flood zones. The flow directions and flood zones of the inner Delta of Niger were obtained from SRTM image (Shuttle Radar Topography Mission) using ArcMap software. The obtained results from the surfaces classification technique “geometrical Interval” have permitted to identify the lowest areas between 258 and 264 m altitude occupying 58% of the total area. Thereafter, the areas favorable for profile tracing are identified through the stretched colour tone. The flow paths leading to these flood zones are detected by the “longitudinal profiles” technique showing downward slope profiles. The whole area dominated by rocky outcrops and by small scattered hills, is endowed of lowlands including a large slit of southwest to northeast direction.