**3. Results and discussion**

Based on the existing formula related to calculation analysis for population pressure, the results are as shown in **Tables 1** and **2** and **Figures 4**–**6**. These results are a combination of spatial calculations with Arc GIS and calculations using Microsof Excel.

The conditions shown in **Table 1**. indicate that there are 3 sub-districts that have level of population pressure on high land, namely Dampit Sub-district, Turen


#### **Table 2.**

*Calculation result related to erosion rate (generated by GIS) of Lesti subwatershed, Malang District – East Java Province, Republic of Indonesia.*

**Figure 5.**

*Indonesia.*

**Figure 4.**

*Province, Republic of Indonesia.*

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

*Map of population pressure conditions in 12 sub-districts of Lesti sub-watershed, Malang District – East Java* 

*Map of current run-off Erosivity of Lesti subwatershed, Malang District – East Java Province, Republic of* 

*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*

#### **Figure 4.**

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

Based on the existing formula related to calculation analysis for population pressure, the results are as shown in **Tables 1** and **2** and **Figures 4**–**6**. These results are a combina-

The conditions shown in **Table 1**. indicate that there are 3 sub-districts that have level of population pressure on high land, namely Dampit Sub-district, Turen

**Number. Sub-sub watershed Area (ha) Result of erosion rate (A) (ton/ha/year)**

tion of spatial calculations with Arc GIS and calculations using Microsof Excel.

 1 2244,760 60,897,267 2 1272,640 223,693,161 3 2585,000 66,900,000 4 4662,400 1,487,060,443 5 171,960 7416,818 6 3090,400 659,022,308 7 317,520 34,850,582 8 2945,280 833,252,748 9 140,480 3113,887 10 2574,120 11,963,945 11 4081,720 17,377,677 12 2224,800 1,056,466,594 13 1464,680 586,835,010 14 1653,560 85,246,379 15 2388,720 108,713,978 16 280,080 6605,734 17 1828,480 71,480,000 18 4787,960 35,165,209 19 1360 521,939 20 4800 933,119 21 2781,720 648,610,551 22 192,040 19,518,057 23 1613,120 429,947,887 24 1898,440 254,515,524 25 1412,760 81,638,228 26 2285,200 182,243,500 27 2224,520 14,097,787 28 1674,480 998,110,000 29 4468,480 283,810,000 30 2922,560 776,230,000 31 4546,800 915,280,000 **Total** 64,740,84 9,961,518,329

*Calculation result related to erosion rate (generated by GIS) of Lesti subwatershed, Malang District – East* 

**3. Results and discussion**

**Table 2.**

*Java Province, Republic of Indonesia.*

*Map of population pressure conditions in 12 sub-districts of Lesti sub-watershed, Malang District – East Java Province, Republic of Indonesia.*

#### **Figure 5.**

*Map of current run-off Erosivity of Lesti subwatershed, Malang District – East Java Province, Republic of Indonesia.*

#### **Figure 6.**

*Map of current erosion rate of Lesti subwatershed, Malang District – East Java Province, Republic of Indonesia.*

**Figure 7.** *Average erosion rate of Lesti sub-watershed from 2006 – Present.*

Sub-district and Gondanglegi Sub-district. If looked at the current land use, several sub-districts identified as having a Population Pressure (TP) > 1 are on open land.

Based on the results of the above calculations, it is known that the total recent erosion rate in the Lesti sub-watershed is 9,961,518,329 tons/ha/year. Considering that the value of the sediment delivery ratio in the Lesti sub-watershed is 8.247%, the amount of sediment in the sub-watershed is 821,556.3 tons/ha/year.

Meanwhile, with the Lesti sub-watershed area of 64,740.84 ha, it can be calculated that the current average erosion rate in each ha of land in the Lesti sub-watershed is 153,868 tonnes/ha/year (exceeding the tolerable erosion rate of 30 tonnes/ ha/year). Previous research results from Yupi [19] stated that the average erosion rate in the Lesti sub-watershed was 30.57 ton/ha/year, and Setyono and Prasetyo's

**67**

**Table 4.**

**Table 3.**

*Source: Analysis Result, 2019.*

*Source: Analysis Result, 2019.*

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

research (2012) was 105.763 tonnes/ha/year. Meanwhile Ma'wa et al. In 2015, the average erosion rate was 131.098 ton/ha/year. **Figure 7**. Based on the results of calculations carried out by the author which states that the current erosion rate is 153.868 tonnes/ha/year, it can be said that there has always been an increase in the erosion rate of the Lesti Sub-watershed since the last 14 years so that better conser-

The erosion rate calculation in the Lesti Sub-watershed is used as a basis for obtaining the extent and information on the Erosion Hazard Level Category (TBE) **Tables 3** and **4**. The values estimate the maximum soil loss that will occur on a land. Spatially, the TBE map makes it easy to see the condition of certain areas as conservation priority areas. TBE map is obtained by overlaying the current erosion rate map, behavior map and population pressure map with the soil solum map in the

Some of the sub-districts identified as having the highest area of Erosion Hazard Levels marked in red on the map are in Wajak Sub-district, Tirtoyudo Sub-district, Dampit Sub-district, Sumbermanjing Wetan Sub-district, Gedangan Sub-district and Bantur Sub-district. As is known Dampit Sub-district, Turen Sub-district and Gondanglegi Sub-district have TP values >1, which means that there has been a population pressure on the land in an area so that it has not been able to meet the

From the standpoint of environmental science, it can be said that erosion which is usually seen from the aspect of carrying capacity of the environment, also has a strong connection with social and economic aspects in the form of pressure. Based on TBE and TP analysis, it was found that 1 sub-district had slices, namely Dampit Sub-district. It is recommended that environmental conservation directives focus

1 A > 90 cm Deep 561,419,204,2 56,141,92,042 86,72 2 B 60–90 cm Medium 68,067,150,77 6806,715,077 10,51 3 C 30–60 cm Shallow 9,930,132,548 993,0132548 1,53

Total 647,408,400,00 64,740,84 100,00

**Area (m2**

**Solum soil**

shallow

 Very light 115,142,109 11,514,21 17,79 Light 113,345,070 11,334,51 17,51 Medium 97,183,967 9718,40 15,01 Heavy 69,542,700 6954,27 10,74 Very heavy 252,194,553 25,219,46 38,95 **Total 647,408,400 64,740,84 100,00**

**) Area (Ha) Percentage (%)**

7,991,912,474 799,1,912,474 1,23

**) Area (Ha) Percentage** 

**(%)**

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

vation management is needed.

Lesti Sub-watershed **Figure 8**.

needs of its population properly **Figure 9**.

**No ID Solum Depth Class of** 

4 D < 30 cm Very

*Data of solum soil depth in Lesti sub-watershed.*

**No Erosion hazard level Area (m2**

*Percentage of erosion hazard level of current Lesti sub-watershed.*

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

research (2012) was 105.763 tonnes/ha/year. Meanwhile Ma'wa et al. In 2015, the average erosion rate was 131.098 ton/ha/year. **Figure 7**. Based on the results of calculations carried out by the author which states that the current erosion rate is 153.868 tonnes/ha/year, it can be said that there has always been an increase in the erosion rate of the Lesti Sub-watershed since the last 14 years so that better conservation management is needed.

The erosion rate calculation in the Lesti Sub-watershed is used as a basis for obtaining the extent and information on the Erosion Hazard Level Category (TBE) **Tables 3** and **4**. The values estimate the maximum soil loss that will occur on a land. Spatially, the TBE map makes it easy to see the condition of certain areas as conservation priority areas. TBE map is obtained by overlaying the current erosion rate map, behavior map and population pressure map with the soil solum map in the Lesti Sub-watershed **Figure 8**.

Some of the sub-districts identified as having the highest area of Erosion Hazard Levels marked in red on the map are in Wajak Sub-district, Tirtoyudo Sub-district, Dampit Sub-district, Sumbermanjing Wetan Sub-district, Gedangan Sub-district and Bantur Sub-district. As is known Dampit Sub-district, Turen Sub-district and Gondanglegi Sub-district have TP values >1, which means that there has been a population pressure on the land in an area so that it has not been able to meet the needs of its population properly **Figure 9**.

From the standpoint of environmental science, it can be said that erosion which is usually seen from the aspect of carrying capacity of the environment, also has a strong connection with social and economic aspects in the form of pressure. Based on TBE and TP analysis, it was found that 1 sub-district had slices, namely Dampit Sub-district. It is recommended that environmental conservation directives focus


#### **Table 3.**

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

Sub-district and Gondanglegi Sub-district. If looked at the current land use, several sub-districts identified as having a Population Pressure (TP) > 1 are on

*Average erosion rate of Lesti sub-watershed from 2006 – Present.*

*Map of current erosion rate of Lesti subwatershed, Malang District – East Java Province, Republic of* 

the amount of sediment in the sub-watershed is 821,556.3 tons/ha/year.

Based on the results of the above calculations, it is known that the total recent erosion rate in the Lesti sub-watershed is 9,961,518,329 tons/ha/year. Considering that the value of the sediment delivery ratio in the Lesti sub-watershed is 8.247%,

Meanwhile, with the Lesti sub-watershed area of 64,740.84 ha, it can be calculated that the current average erosion rate in each ha of land in the Lesti sub-watershed is 153,868 tonnes/ha/year (exceeding the tolerable erosion rate of 30 tonnes/ ha/year). Previous research results from Yupi [19] stated that the average erosion rate in the Lesti sub-watershed was 30.57 ton/ha/year, and Setyono and Prasetyo's

**66**

open land.

**Figure 7.**

**Figure 6.**

*Indonesia.*

*Data of solum soil depth in Lesti sub-watershed.*


#### **Table 4.**

*Percentage of erosion hazard level of current Lesti sub-watershed.*

#### **Figure 8.**

*Map of soil solum of Lesti subwatershed.*

## **Figure 9.**

*Map of current erosion hazard levels of Lesti sub-watershed.*

on the sub-district through the application of technical, vegetative, agronomic, land and water civil conservation as well as a combination involving the community and in accordance with local conditions.

**69**

**Author details**

Andi Setyo Pambudi

**Acknowledgements**

Kota Jakarta Pusat, Indonesia

andi.pambudi@bappenas.go.id

provided the original work is properly cited.

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

Sub-district because it is an area with high TP slices and heavy TBE.

ment programs undertaken to prevent erosion in the upstream watershed.

parties who assist in writing, both technical and non-technical.

Based on the results of data analysis and discussion, it can be concluded that the Lesti Sub-watershed, there is a correlation between population pressure and the current choice of land use, which results in erosion vulnerability. At high population pressure (> 1) in general is directly proportional to the erosion-prone land use conditions such as settlements, dry land fields and open land. Based on environmental science, the government needs to balance economic, social and environmental needs in several regions. Priority for conservation is prioritized in Dampit

The recommendation that can be given to this sub-district is the provision of subsidies or incentives by the government for people who want to carry out agricultural efforts with conservation principles. This is to reduce the income gap because in some cases of agricultural output will decrease when applying the principle of environmental conservation. In the social aspect, efforts are needed to involve the community with their local wisdom to carry out conservation efforts, both technical civil, agronomic and vegetative so that there is a sense of ownership of govern-

The authors gratefully thanks to Director Agustin Arry Yanna, SS, MA; Prof. Drs. Raldi Hendrotoro Seputro Koestoer, M.Sc., Ph.D.; Prof. Dr. Ing. Ir. Dwita Sutjiningsih, Dipl. HE; Dr. Muchamad Saparis Soedarjanto, M.T., S.Si; Rahmad Junaidi, ST, MT; Sri Hidayati. S.Si, M.Han; Dr. Hayati Sari Hasibuan, ST, MT and all

Postgraduate School of Environmental Sciences, University of Indonesia, Salemba

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

Campus, Jl. Salemba Raya No. 4, Kampus UI Salemba, Kenari, Kec. Senen,

\*Address all correspondence to: andisetyopambudi@gmail.com;

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

**4. Conclusion**

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