home    land degradation    project outcome    Gallery Flooding Flood Hazard Assessment Pilot Area • The Pilot Areas • Climate • Cover factor (C) estimation • Digital terrain analysis • Relationship between soil properties • Relationship of soil properties with different land use/cover types Methodology • Methodologies • LISEM Results • Result Soil Properties and Land Use • Runoff rate for different land cover types • Model calibration and validation • Sensitivity analysis • Land use scenarios • Rainfall size scenarios • Flooding Scenario - 2 years return period • Flooding Scenario - 10 years return period • Flooding Scenario - 20 years return period • Flooding Scenario - 50 years return period • Summary tables for each flood characteristic • Flood hazard mapping • Conclusions and Recommendation Erosion Erosion Assessment Pilot Area • The Pilot Areas • Climate • Cover factor (C) estimation • Digital terrain analysis • Relationship between soil properties • Relationship of soil properties with different land use/cover types Methodology • Methodologies • Erosion Models Result • Results • C-Factor Mapping for erosion assessment • Soil erosion assessment • Assessment of land use/cover change effect on soil erosion • Assessing critical zones for ephemeral gully formation • Erosion Assessment by Different Models • The recommended erosion models • RMMF Landslide Case I • Landslide hazard assessment • The area (Pilot 3) • Landslide Mapping in Wang Chin using digital image analysis Techniques. • Results • Discussions Case II • Doi Ang Khang (Ang Khang) (Pilot area 4) • Landslide mapping in Ang Khang using aerial photos • Landslide Inventory Mapping • Landslide modelling and Susceptibility mapping • Landslide Susceptibility Maps from the three Scenarios (models) • Comparison between Ang Khang and Wang Chin (with respect to weights of evidence modelling using morphometric parameters) Salinization Case I • Pilot area II • Soil salinity • Salinization • Geomorphology • Soils • Geopedologic map • Results Case II • CASE II - The study of Yadav, R.D. (2005), • Methodology • Crop Simulation Model • PS 123 • Results • Mathematical (Regression) Model for Crop Yield Estimation • Conclusion Case III • Case III • Modeling Salinization • Geostatistics and Interpolation (GIS and Kriging) • Model Simulation and Prediction of Salinity • Simulated Depth to water table • Tenth Years Prediction • Twenty Years Prediction • Conclusion Runoff • Surface Runoff • Methodology • Modelling Runoff • Modelling Runoff Using Empirical Approach • Modelling runoff using the Semi-physical approach • Estimation with the Curve Number Method • Results and Discussion • Generation of Scenarios • Comparison of runoff rates with soil loss map • Conclusions • Presentation of papers based on project work at international • Workshop in Lomsak • Hua Hin seminar • Training of LDD staff • GIS and RS based predictive soil mapping • Soil erosion assessment • Landslide hazard assessment • Flood hazard assessment • Soil salinity study • List of completed MSc. theses on project RELATIONSHIP OF SOIL PROPERTIES WiTH DIFFERENT LAND USE/COVER TYPES Infiltration has a reducing effect on the volume of runoff that is generated in a catchment (Schwab et al., 1981). Certain soil properties play an important role in determining the amount of water that can infiltrate into the soil for a given rainfall event. These properties can serve as indicators on the effects of different land use/ cover types on the soils capability to take in water in the long run influencing the amount of water that will be available for runoff. Selected soil properties were therefore assessed in relation to major land use/cover types in the watershed and in relation to one another. The soil properties considered for the land use/ cover-soil relationship study include; soil organic matter content, porosity, bulk density and saturated hydraulic conductivity. In addition to these, on site infiltration tests were also conducted to asses if any relationship with the different soil properties could be observed.   Figure 1 : Variation of soil properties in different land use/ cover types.     Variability of soil properties on different land use/ cover types.       The box plots in figure 6-3 show the variation of soil properties on different land use/cover types. Hydraulic conductivity and infiltration rate appear to be high in forested areas and much lower in cornfields. Soil porosity appears to exhibit the same trend as well. On the other hand, bulk density showed highest values in cornfields and lowest in forest areas. The cultivation of maize in the area is done mainly by means of mechanised ploughing (Shrestha, 2003). This brings about compaction which increases soil bulk density (Hillel, 1980). Thus the high bulk density in areas of corn cultivation could be attributed to land use/ cover practices. Moreover, high variation of bulk density was observed on grassland areas. This could be attributed to the fact that some grassland areas in the watershed were in the past used for maize cultivation. Organic matter content seems to show the most variation on cornfields and this could be due to the influence of management practices.   Development of Methodologies for Land Degradation Assessment Applied to Land Use Planning in Thailand ^go to top