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CHAPTER V

CONCLUSSION

5.1. RESULT

From this research the author obtained much good additional knowledge.

Many new things that can be observed, studied and became a valuable experience,

be it in science, as well as moral messages. There are several result of this research

below:

a. Based on the estimation of amount of debris flow in Gendol river about

1547899.16 m3.

b. Based on the estimation of the capacity volume of sediment control

structure (sabo) in Gendol river about 1165838.60 m3.

c. There are 382060.56 m3 sediment cannot accommodated by the sediment

control structure (sabo) in Gendol river.

d. In conclusion the sediment control structure in Gendol river is ineffective

to mitigate the losses during the debris flow.

e. There is six suggested sediment control structure that should be built to

anticipate the losses during debris flow.

f. After adding six sediment control stricture (sabo) capacity of sediment

control structure become 1553110.18 m3.

g. Furthermore, the sediment control structure along Gendol river is only

accommodate 75% from the total debris flow 1547899.16 m3 or

68

1165838.60 m3 only that mean there 25% or about 382060.56 m3 losses

sediment flow and harmful for the downstream area.

h. Sand mining is recommended in order to keep the structure in good

condition so the structure can work properly

i. Beside that construct another sediment control structure in Gendol river

become the best solution to minimize the losses sediment.

In order to balancing the sediment and the structure, six Sediment control

structure should be added on the Gendol river. The detail information about those

six sediment control structure (sabo) see Table 4.6 Balanced Sediment.

a. The first recommendation structure is located on Glagasari which

dimension is 13.00 m height and 80.00 m width that can accommodate

around 108488.20 m3 of sediment from debris flow. The second

recommendation structure is located on Sindumartani dimension is 8.00 m

height and 70.00 m width that can accommodate around 58416.72 m3 of

sediment from debris flow.

b. The next recommendation structure is located on Agromulyo with

dimension 6.50 m height and 65.00 m width this structure can

accommodate around 44073.33 m3 of sediment from debris flow.

c. The next recommendation structure is located on Kepuharjo with

dimension 13.00 m height and 70.00 m width this structure can

accommodate around 94927.17 m3 of sediment from debris flow.

d. The next a couple’s structure is located on the downstream of GE-C0

(Tulung) separate on different elevation with the dimension about 6.0 m

69

height and 65.00 m width each structure can accommodate around

40683.07 m3 of sediment from debris flow.

For more information about location of proposed six sediment control

structure shows on the figure below. See Figure 5.1 Suggestion of New Sediment

Control Structure Location.

5.2. RECOMMENDATION

Based on this research the author would like to give some recommendation

for related parties.

a. There are many sediment control structure distributed into several rivers

from Merapi. And every instance has their own data about the sabo. This

make the information is scattered and incomplete. This make the

monitoring harder, because the specification data and the other record are

hold by other organization. Therefore, making a centralized data base,

which every instance can access, will make the data easier to analyze and

complete. This will also make research in sediment control structure

become easier.

b. Rehabilitate and repair the damaged building.

c. Conducted investigation to assess the damages in the building based

on existing procedure.

d. Forming a community to give knowledge to the society about the

sediment controlling structure and its benefits.

70

e. With a good awareness of the society about the benefits of the

sediment controlling structure, therefore the society will also protect the

structure so it can always be operated in a good condition.

71

72

Figure 5.1 Suggestion of New Sediment Control Structure Location.

73

REFERENCES

Chairil, S. Setyono, E, Hidayat, R.F., 2012 Analisis Peningkatan Kapasitas

Kantong Lahar Kali Regoyo Desa Regoyo Kabupaten Lumajang.,

Jurusan Teknik Sipil Universitas Muhammadiyah Malang

Dedi, S., Heru, A.S., and Surendro A.W., Fikri, A.K., Maria. U., 2015 Pengendalian

Aliran Sedimen Pada DAS Kali Mujur Gunung Semeru, on Annual Report

of Depatemen Pekerjaan Umum PPK Penanganan Bencana Sedimen.

Kementrian Pekerjaan Umum Direktorat Jenderal Sumber Daya Air Direktorat

Sungai dan Pantai Satuan Kerja Direktorat Sungai, Danau dan Waduk

Kegiatan Penanganan Sedimen, 2006, Desain Sabo, ISBN 978-602-96989-

4-7

Joesron, L., 1986, Banjir Rencana untuk Bangunan Air, Departemen Pekerjaan

Umum.

Mukhlisin, 1998, Pengaruh Curah Hujan Terhadap Pembentukan Aliran Debris,

Tesis Magister, Progran Studi Teknik Sipil, Sekolah Pascasarjana Fakultas

Teknik, Universitas Gajah Mada, Yogyakarta

Nobutomo, O, Mizuno, H, and Mizuyama, T., 2010 Design Standard of Control

Structures Against Debris Flow in Japan, on Erosion and Sediment

Control Division, Research Center for Disaster Risk Management, National

Institute for Land and Infrastructure Management, Ministry of Land,

Infrastructure, Transport and Tourism, Japan

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Priyantoro, D, 1987, Teknik Pengangkutan Sed imen , Fakultas Teknik Jurusan

Pengairan Universitas Brawijaya Malang.

Departemen Permukiman dan Pengembangan Wilayah Direktorat Jenderal

Pengembangan Perdesaan, 2000(a), Draft Manual Perencanaan Sabo,

Proyek Pengembangan dan Rekayasa SABO.

Departemen Permukiman dan Pengembangan Wilayah Direktorat Jenderal

Pengembangan Perdesaan, 2000(b), Contoh Aplikasi Perencanaan SABO,

Proyek Pengembangan dan Rekayasa SABO.

Rahmat, A., Djoko, L., and Haryono K., 2010 Pengelolaan Sedimen Kali Gendol

pasca erupsi 2006 An Journal of Sabo Technical Center 2010.

Takahashi T., Nakagawa H. and Kuang S. (1987): Estimation of debris

flow hydrograph on varied slope bed. Erosion and Sedimentation in

the Pacific Rim, IAHS Publ. 165, pp. 167–177

Voight, 2000, Historical of Merapi Volcano, Central Java Imdonesia. 1768-1998.

Journal of Volcanology and Geothermal Research.

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ATTACHMENT

77

23836.21397

84102.91639

24689.38086

92086.1413

11584.07278

28008.743730103.59922

9693.313953

19252.20836

18526.29621

17250.36923

11488.88296

17516.25

1558.055491

9176.37306611524.6868

49820.87905

9411.057692

10334.25

12177.06489

2507.7871364996.570236

0

10000

20000

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50000

60000

70000

80000

90000

100000V

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Static Volume

78

31781.619

112137.222

32919.174

122781.522

15445.430

37344.99240138.132

12924.419

25669.611

24701.728

23000.492

15318.511

23355.000

2077.407

12235.16415366.249

66427.839

12548.077

13779.000

16236.087

3343.7166662.094

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Dynamic Volume

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55,617.83

196,240.14

57,608.56

214,867.66

27,029.50

65,353.74 70,241.73

22,617.73

44,921.82

43,228.02

40,250.86

26,807.39

40,871.25

3,635.46

21,411.54 26,890.94

116,248.72

21,959.13

24,113.25

28,413.15

5,851.50 11,658.66

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Storage Volume of Sediment Control Structure at Gendol River

Static Volume Dynamic Volume Total