SOIL EROSION ASSESSMENT BY USING REVISED MORGAN-MORGAN FINNEY (RMMF)
MODEL IN A GIS FRAMEWORK IN A MOUNTAIN WATERSHED OF NEPAL
Abstract
Soil erosion poses a significant environmental concern and threatens
natural resources, resulting in decreased productivity and quality of
soil. In Nepal, soil erosion arises from both natural factors such as
excessive rainfall, weak geology, earthquakes, and human activities
including deforestation, overgrazing, intensive agriculture, and
unplanned infrastructure construction. A research study titled ”Soil
Erosion Assessment using the Revised Morgan, Morgan Finney (RMMF) Model
in a GIS Framework” was conducted in the Manahari Khola Sub-watershed of
the Makwanpur district. The primary objective of the study was to
evaluate the extent of soil erosion under the current Land Use and Land
Cover (LULC) conditions. To perform the model, essential databases such
as LULC parameters, soil parameters, rainfall parameters, and Digital
Elevation Model (DEM) were generated using Landsat Images, landform maps
based on FAO guidelines, data from the Hydrology Department, and Google
Earth. The software tools ArcGIS 10.8 and ILWIS 3.3 Academic were
utilized. The results of the RMMF soil erosion modeling indicated
varying levels of soil erosion risk, ranging from Very Low to Very High.
It was observed that forest and bush areas experienced lower rates of
soil erosion, while barren land showed higher erosion rates.
Additionally, the erosion susceptibility map illustrated that forested
regions had a very low risk of soil erosion, followed by low to moderate
risk in agricultural areas. Barren areas exhibited moderate to very high
susceptibility to soil erosion. The study emphasized the need for proper
conservation of cutting and cliff areas as well as barren land within
the watershed due to their high to very high potential for soil erosion
risk. Recommendations for the future included afforestation in barren
areas, implementation of conservation farming practices in agricultural
regions, and adoption of appropriate road stabilization measures.