Row | Erosion factor | Score | Description |
1 | Surface geology (0 - 10) | 4.4 | 25% of the basin with very high erosion 10%of the basin with high erosion 23% of the basin with very low erosion (0.25 × 10 + 0.10× 8 + 0.42 × 1) = 4.4 |
2 | Soil (0 - 10) | 5 | Moderate texture with boulders X = 0.2p2 |
3 | Weather (0 - 10) | 8.4 | The amount of rainfall within 6hrs with a two-year-return-cycle P2 = 42 (mm) X = 0.2 × 42 = 8.4 X = 0.006R + 10Q |
4 | Runoff (0 - 10) | 3.2 | The height of the annual runoff R = 247 (mm) The special discharge of flood with a-two-year-return-cycle Qp = 0.167 (m3/sec/km2) X = 0.006 × 247 + 10 × 0.167 = 3.2 X = 0.338 |
5 | Unpaved areas (0 - 20) | 13.5 | S = 41 the moderate slope of the basin(mm) X = 0.33 × 41 + 13.5 X = 0.2pb |
6 | Plant coverage (−10 to +10) | 7 | pb = 35 the percentage of stiff lands without coverage X = 0.2 × 35 = 7 X = 20 − 0.2B |
7 | Lands usage (−10 to +10) | 5 | B = 75 the percentage of the plant coverage X = 20 − 0.2 × 75 = 5 |
8 | High land erosion (0 to 25) | 10 | The presence of different types of erosion about 25% of the lands-moderate erosion |
9 | River erosion and sediment transportation (0 - 10) | 8 | Flow with moderate continuity and depth with moderate river side or bed erosion |