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Maja Turajlija

Maja Turajlija. Definition. Erosion is the process by which soil and rock are removed from the Earth's surface by processes such as wind or water flow, and then transported and deposited in other locations. Forms of erosion. Surface Erosion

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Maja Turajlija

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  1. MajaTurajlija

  2. Definition Erosion is the process by which soil and rock are removed from the Earth's surface by processes such as wind or water flow, and then transported and deposited in other locations.

  3. Forms of erosion • Surface Erosion • The effect on a soil surface after being worn away • from abrasion or weathering. (e.g. construction sites) • Fluvial Erosion • Erosion by moving water • Mass- movement Erosion • Soil gets saturated by rain and top layer might get • detached and slip downhill exposing underlying matter. • Stream Channel Erosion • Stream bed erosion connected with bank erosion

  4. Soil Erosion Risk Assessment • Determination of quantitative and qualitative values of soil erosion risk. • Necessity to distinguish erosion vulnerable areas and implement all possible mitigating measures.

  5. Reasons for risk assessment: • Objective evaluation of soil condition • Estimation of average rate of erosion, loss of • soil and economic outcomes • Probability and distribution of erosion events, • loss of production, offsite deposition • Mitigation and remediation connected with • allocation of resources • Assessment of impact of changing climate • conditions on soils (EEA, 2002)

  6. Risk Assessment approaches: • Expert based approach • Model based approach • assessing soil erosion risk by the use of • different erosion models scoring criteria of various factors established by experts for small scale areas.

  7. Expert based approach CORINE (coordination of information on environment) European program, aimed at gathering information relating to the environment on certain priority topics for the European Union. Purpose: land cover observation Advantages: simplicity and objectiveness

  8. Model based approach • estimate future yearly soil degradation • forecast particular rainfall losses • lumped models • spatially distributed models • empirical models • physically-based models • It is difficult to validate output data obtained on larger scale since data for such big areas are poor or do not exist at all.

  9. Universal Soil Loss Equation (USLE) A = R x K x L x S x C A…mean annual soil loss R… rainfall erosivity factor K… soil erodibility factor L… slope factor (topographical unit) S… slope length factor (topographical unit) C… cover management factor Average annual values are calculated for every factor!

  10. Revised Universal Soil Loss Equation A = R x K x L x S x C USLE RUSLE | | | | | | | | | | | A…mean annual soil loss R… rainfall erosivity factor K… soil erodibility factor L… slope factor S… slope length factor C… cover management factor A…mean soil loss R… rainfall erosivity factor K… time-varying soil erodibility factor L… slope factor S… slope length factor C… cover management factor has a set of subfactors for evaluation

  11. Study Area A small mountainous sub-watershed in Pamba river basin, Kerala, India 167.83 km2

  12. Methodology Models used: • Universal Soil Loss Equation and Revised Universal Soil Loss Equation (USLE/RUSLE) • Water Erosion Prediction Project (WEPP) • Soil Erosion Model for Mediterranean Regions (SEMMED) • Areal Non-point Source Watershed Environment Response Simulation (ANSWERS) • Limburg Soil Erosion Model (LISEM) • European Soil Erosion Model (EUROSEM) • Soil and Water Assessment Tool (SWAT) • Simulator for Water Resources in Rural Basins (SWRRB) • Agricultural Non-point Source pollution model (AGNPS) • Data collection sources: • Indian Meteorological Department (IMD) • Satellite image • Soil texture map of soil survey organization • Kerala and Survey of India (SOI) toposheets.

  13. Results The average soil erosion rate estimated for the upland sub-watershed ranges from 0 to 17.73 t h-1 y-1 with a standard deviation of 0.975 t h-1 y-1 Figure 1

  14. Results 92% of the study area is classified as low potential erosion risk (<1.5 t h-1 y-1), while rest of the area is under moderate to high erosion risk.

  15. Results To assess the role of human intervention in the soil erosion risk in the sub-watershed, land use/land cover map (figure 2) of the area was overlaid with classified soil erosion risk zone map. Figure 2

  16. Conclusion In the sub-watershed the land use pattern in areas prone to soil erosion indicates that areas with natural forest cover in the head water regions have minimum rate of soil erosion while areas with human intervention have high rate of soil erosion (>5 t h-1 y-1). Terrain alterations along with rainfall prompt these areas to be more susceptible to soil erosion. This predicted amount of soil loss and its spatial distribution can provide a basis for comprehensive management and sustainable land use for the watershed. The areas with high and severe soil erosion warrant special priority for the implementation of control measures.

  17. Thank You for your attention!

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