*Soil Erosion - Current Challenges and Future Perspectives in a Changing World*

#### **Figure 3.**

*Flow analysis of erosion rates and erosion Hazard levels in Lesti sub-watershed.*

$$
\mathbf{A} = \mathbf{R\_W} \times \mathbf{K} \times \mathbf{L} \mathbf{S} \times \mathbf{CP} \tag{5}
$$

$$
\text{where } \mathbf{R\_W} = \mathbf{9}, \mathbf{05} \left( \mathbf{V\_o} \times \mathbf{Q\_p} \right)^{0.56}
$$

Note:


Runoff discharge (Qp) is calculated in relation to the surface runoff erosivity (Rw) as part of the MUSLE method erosion estimation formula. In order to get runoff discharge data, several steps are needed, namely: 1) Determining the Flow Coefficient (C); 2) Determine the Concentration Time (Tc), Reservoir Coefficient (Cs) and Rainfall Intensity (I); 3) Calculate runoff discharge and describe it in the form of Run-off Discharge Distribution Maps (surface runoff) in various times with ArcGIS 10.3.

The next step is the calculation of runoff discharge. Determination of the amount of runoff discharge is done through overlays with ArcGIS software. This analysis is done through geoprocessing analysis on ArcGIS 10.3 software. The data used are in Lesti Sub-watersheds (Coefficients Cs and I), land use maps (for C Coefficient). The formula used is the modified rational runoff equation, namely:

$$\mathbf{Q} = \mathbf{0}, \mathbf{0}0278. \text{ C.s. C. I. A} \tag{6}$$

**63**

**Sub-districts in Lesti sub-watershed**

Poncokusumo

Wajak **Dampit** Tirtoyudo Sumbermanjing Wetan

**Turen** Bululawang **Gondanglegi** Ampelgading

Gedangan

Bantur

Pagak *Source: Analysis Result, 2019.*

**Table 1.**

24.739 107.607

12.282 82.052 14.823 12.032 20.384

7.683

7.123 *Level of population pressure on land (bold values showed Area with high populationpressure in Lesti-Sub-Watershed).*

0,93

1,49

13.051

0,64

0,66

0,26 0,26

5.043

0,42

0,19

9.084

0,69

1,24

0,16 0,26

57.984

0,70

1,50

4.927

0,40

0,72

0,16 0,16

61.445

0,57

1,68

15.099

0,61

1,47

0,19 0,16

26.221 74.121 108.914

44.121

28.991

0,66

1,44

0,17

89.087

0,82

1,50

0,19

66.292

0,89

1,20

0,19

24.460

0,93

1,53

0,17

4.226,381 4.621,481 8.361,963 3.029,741 1.548,180 3.713,927

209,196 5.444,617

307,824 1.329,656 1.757,160 1.082,391

0,97,542 0,87,528 **361,627** 0,86,021 0,55,234 **368,583** 0,00427 **195,847** 0,13,464 0,00001 0,01192 0,38,289

< 1

< 1

< 1

< 1

**> 1**

< 1

**> 1**

< 1

< 1

**> 1**

< 1

< 1

**Total population**

**Number of farmers**

**Proportion of farmers**

**Growth rate population**

**Minimum land area decent life**

**Agricultural land area (Ha)**

**Value of population pressure**

**Criteria**

*Determination of the Most Priority Conservation Areas Based on Population Pressure…*

*DOI: http://dx.doi.org/10.5772/intechopen.95386*


*Determination of the Most Priority Conservation Areas Based on Population Pressure… DOI: http://dx.doi.org/10.5772/intechopen.95386*

> **Table 1.**

*Level of population pressure on land (bold values showed Area with high populationpressure in Lesti-Sub-Watershed).*

*Soil Erosion - Current Challenges and Future Perspectives in a Changing World*

**A R K LS CP** = ×× × **<sup>W</sup>** (5)

0,56

Q = 0,00278. Cs. C. I. A (6)

where ( )

R 9,05 V Q W Op = ×

**62**

Note:

**Figure 3.**

• A = Erotion Rate (ton/ha/tahun)

• VO = Surface runoff volume (m3

• K = Soil erodibility factor

• LS = Slope factor

with ArcGIS 10.3.

tion, namely:

• RW = Surface runoff erosivity index *(run-off)*

*Flow analysis of erosion rates and erosion Hazard levels in Lesti sub-watershed.*

• CP = Factors of land use and land management

)

Runoff discharge (Qp) is calculated in relation to the surface runoff erosivity (Rw) as part of the MUSLE method erosion estimation formula. In order to get runoff discharge data, several steps are needed, namely: 1) Determining the Flow Coefficient (C); 2) Determine the Concentration Time (Tc), Reservoir Coefficient (Cs) and Rainfall Intensity (I); 3) Calculate runoff discharge and describe it in the form of Run-off Discharge Distribution Maps (surface runoff) in various times

The next step is the calculation of runoff discharge. Determination of the amount of runoff discharge is done through overlays with ArcGIS software. This analysis is done through geoprocessing analysis on ArcGIS 10.3 software. The data used are in Lesti Sub-watersheds (Coefficients Cs and I), land use maps (for C Coefficient). The formula used is the modified rational runoff equa-
