DEVELOPMENT OF SOIL EROSION INDEX MODEL IN TAIWAN WATERSHEDS

1 INTRODUCTIONSoil erosion of land surface caused by over development has become more and more serious.Environmental damage resulted from accelerated soil erosion has attracted much attention especi ally overthe past 20 years. Soil erosion stUdies have focused primarily on soil characteristics and climaticvariations. Great achievements have been made in understanding the mechanism of soil erosion, whichallows the develoPment of evaluation models for all types of soil erosion problems. Th…

DEVELOPMENT OF SOIL EROSION INDEX MODEL IN TAIWAN WATERSHEDS

With steep terrain and excessive rainfall, Taiwan is affected by severe soil erosion caused by summer typhoons and storms that bring intensive rainfall and rapid fl . However, the actual erosion is much less than the value predicted by the USLE because the soil erosion types in Taiwan are different from those in America which has mild slope and dry weather. Developing a soil erosion index model applicable to Taiwan is the important goal of this research. Five factors, namely, soil texture, rainfall type,slope steepness, ground cover and land use, are included in this model. Soil index factor is measured by Km from the USLE model, and other index factors are calculated from local field data. The soil erosion index model (SEIM) is as follows:SE = 6 × 10-7 AI for AI≤ 50 SE = 0.233AI1.8 for AI ＞ 50 where Al is the total index value, and SE is the soil erosion quantity (ton/ha/yr). After being properly calibrated and verified, SEIM proves to be useful in planning soil and water conservation, and assessing soil erosion impacts in Taiwan.