Application of GIS [geographic information systems] in determining soil erosion potentials of the lower Magat Watershed in Nueva Vizcaya, PHilippines
2000
Cambalicer, E.A.
The current soil erosion rates at different levels of soil erosion ranged from 0.204 to 144.25 tons/ha/yr. The average soil loss for the entire watershed was estimated to about 17.24 t/ha/yr with the total soil loss of 109,049.72 t/yr. The highest current erosion rate was observed on steeper slopes, arable land, clay loam and 84 R-value. The lowest current erosion rate was found on the gentle slopes, secondary forest, sandy loam and 167 R-value. The potential soil erosion rates ranged from 0 to 200.98 t/ha/yr. The average soil loss for the entire watershed was estimated to be 42.077 t/ha/yr which translates to 1,753,848.98 t/ha/yr. In terms of slope distribution, the lowest potential erosion rate was observed on gentle slopes of the previously river bed area (block 3), clay loam and 84 R-value, while the highest was found on the steeper slopes previously grassland area (block 4), sandy loam and 167 R-value. The average soil erosion index of the watershed was 1.683. In terms of slope distribution, the highest index was estimated in block 4 while the lowest was found in block 2. The erosion index less than or equal to one was classified as production areas. On the other hand, the erosion index greater than one was categorized as protection areas. The results show that about 41.04% was suitable for agricultural purposes while the remaining 58.96% was strictly for protection activities. The study showed that GIS is a powerful tool for determining soil erosion potentials of the study area. GIS makes data analysis easier, faster and systematic among other things
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