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<p><strong>Abstract.</strong> Channel migration becomes the main characteristic of major rivers of Mohana-Macheli watershed of western Nepal. Study of river channel migration of major rivers of watershed using freely available remote sensing show that the channel has shifted to as high as 1000 meters from the original river path over the span of 9 years (2009–2017). The channel migration directly affects the land use and it has direct effect on the flood plain settlements of the study area. Cultivation of sugarcane in sand area is one of the mitigating measures of flood effects and prevent river bank erosion. The study shows that the area of sand is changing disproportionately in the region. This paper presents an enhanced change detection method of river channel migration using remotely sensed images and identification of sand area using classification and interpretation technique.</p>

Abstract. Digital Elevation Models are one of the important datasets of any Geographic Information System (GIS) and so are the parameters derived from them. One such parameter is slope, whose accuracy can have a significant effect on many engineering and construction works. This paper addresses the eight-slope calculation methods that are currently available to calculate slope value from a DEM and compares how these methods works on different slope range and values. These methods were applied to calculate slope from DEM of 30 m. To determine the method that calculates the most accurate slope value for a particular slope range by comparing them with actual slope value is the main objective of this paper. The methods 2FD, 3FD, 3FDWRD, Average Neighborhood, Constrained Quadratic Surface and FFD has given similar results across all slope range while the algorithms that appears to yield the most varying results are Maximum Max and Simple D. In addition, it is observed that the choice of algorithms is more important when grade slope is less than 10 percent. However, for terrains with above 10 percent slope, the choice of algorithms seems less important with only a difference of approximately 0.5 gradient.