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 หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Internet GIS, Based on USLE Modeling, for Assessment of Soil Erosion in Songkhram Watershed, Northeastern of Thailand) ผู้เขียน: ดร.ศุภกิจ นนทนานันท์, รองศาสตราจารย์ ,  บุรินทร์ ช้างน้อย สื่อสิ่งพิมพ์:pdf AbstractA web-based geographic information system (GIS) was designed and implemented, which included a database designed to accommodate, organize and manipulate basic spatial data as well as interrelate data from various sources. The system was used to produce erosion susceptibility maps for regions of Upper Northeastern Thailand—an area that has suffered from inappropriate land use practice. GIS-based methods were proposed and applied to data from the Songkhram sub basin in the Songkhram watershed. ArcGIS software was used to derive land use, land cover and topographical data for the watershed. An open source GIS (QGIS) and the Geographic Resources Analysis Support System (GRASS) package were used to carry out geographical data analysis and database management system (DBMS) implementation, both of which were implemented by Postgres Plus software. The watershed was mapped into topographically and geographically homogeneous grid cells to capture watershed heterogeneity. The soil erosion in each cell was calculated using the universal soil loss equation by carefully determining its various parameters and classifying the watershed into different levels of soil erosion severity. The results showed that during the study period, the area had soil loss over a tolerance value (12.5 t.ha-1.yr-1) which ranged from the moderate class up to the very severe class of susceptibility. Moreover, it was also found that the amount of soil erosion increased from 762 km2 in 2006 and to 1,123 km2 in 2010. The outcome of the study was published on the Internet using UMN map server software as well as by using Google map. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Prediction of Soil Loss in the Northern Part of Somali Region of Ethiopia Using Empirical Soil Erosion Models) ผู้เขียน:Sultan Welle, ดร.ก่อโชค จันทวรางกูร, รองศาสตราจารย์ , Supakij Nontanandh, นายสมเจตน์ จันทวัฒน์, ศาสตราจารย์ สื่อสิ่งพิมพ์:pdf AbstractTwo empirical soil loss models, namely Universal Soil Loss Equation (USLE) and Soil Loss Estimation Model for Southern Africa (SLEMSA) were applied to assess extent of erosion hazard at 12 selected sites in the northern part of Somali region of Ethiopia. The amount of estimated soil loss for 10 out of 12 sites by using the USLE is by two to three and half times greater than that estimated by SLEMSA. The difference between the values of soil loss estimated by the two models can be attributed to the difference in the sensitivity of the models to their input factors. In general, since SLEMSA under estimate the amount of soil loss from a given site, it is recommended to use USLE to estimate soil loss in the northern part of the Somali region of Ethiopia. The sensitivity of both models to their 20% increase or decrease in one of their input variable at a time while keeping other variables constant was analysed. The analysis indicated that USLE was highly sensitive to slope gradient factor (S), soil conservation practice factor (P) and rainfall erosivity factor (R) but less sensitive to slope length (L) and vegetal cover factor (C). Whereas, SLEMSA was ighly sensitive to change in rainfall kinetic energy (E) and soil erodibility (F) and was less sensitive to slope gradient (S), slope length (L) and percent cover factor (C). |