|
|
|
Poster Session 1
|
Watershed Prioritization For Soil Conservation Planning With
Mos-1 Messr Data, Gis Applications And Socio- Economic
Information
A Case Study Of Tinau Watershed, Nepal
Low, medium and high erosion areas were defined for each parameter affecting soil erosion as shown in Table 1 and then final soil erosion overlaying such thematic maps for each parameter developed status map.
Table 1 SES weightage score for different parameters.
| Parameter |
Categories |
Relative erosion |
Score for SES |
| Aspect |
North, North-east, North-west |
Low |
1 |
| East and West |
Medium |
2 |
| South, South-east and South-west |
High |
3 |
| Slope gradient |
<15% |
Low |
1 |
| 15-30% |
Medium |
2 |
| >30% |
High |
3 |
| Drainage density |
No drainage in 500*500 m grid |
Low |
1 |
| Drainage yes, but no 1st and 2nd order stream |
Medium |
2 |
| 1st and 2nd order steams in grid |
High |
3 |
| Soil types |
Clayey |
Low |
1 |
| Loamy |
Medium |
2 |
| Sandy |
High |
3 |
| Land use/cover |
Forests>40% crown cover, tars, valley cultivation, rocky areas |
Low |
1 |
| Forests 10-40% crown cover, level terraces cultivation, shrub lands |
Medium |
2 |
| Forests <10% crown cover, sloping terraces cultivation, gully and land slide area, system side 100 meters |
High |
3 |
After making such thematic maps classifying the study area into LEA (low erision area),MEA (medium erosion area)and HEA (high erison area) for each parameter, a final map of soil erosion status was developed for showing the erosion status of defferent subwatershed within the study area. The flow chart of those steps in generating soil erosion status map is given in Figure1.
SES=[{(LEA*10)+(MEA*20)+(HEA*30)}/Total Area]
Figure 1: Flow chart showing the methods for evaluation soil erosion status (SES)
|
|
|
|
|
|
|
