Mitigation of Environmental Degradation in Merapi Volcano Disaster-Prone Area: A Case Study of Klaten District

Journal of Environmental Treatment Techniques

2020, Volume 8, Issue 3, Pages: 988-998

J. Environ. Treat. Tech.

ISSN: 2309-1185

Journal web link: http://www.jett.dormaj.com

Mitigation of Environmental Degradation in

Merapi Volcano Disaster-Prone Area: A Case

Study of Klaten District

Widodo Brontowiyono* , Lupiyanto R. , J. Hamidin , Julianto E. A , Widyastuti A ,

Harmawan F. and Supriyo

Department of Environmental Engineering, Universitas Islam Indonesia (UII), Yogyakarta, Indonesia

Center for Environmental Study, Universitas Islam Indonesia, Yogyakarta

Karunia Sejahtera, Yogyakarta, INDONESIA

Dept. of Agrotechnology, University of Pembangunan Nasional “Veteran” Yogyakarta Doctor Candidate, Faculty of Economy, UII

Received: 06/01/2020 Accepted: 13/04/2020 Published: 20/09/2020

Abstract

Eruptions of Mount Merapi have provided economic benefits, including increased soil fertility and abundant sand and stone. As time

goes by, mining has been spreading to yards, getting uncontrolled and disregarding rules as well as good management. As a result,

environmental degradation, particularly land criticality, is highly likely to occur. This study was conducted to identify the levels of land

criticality in the slope of Merapi. The output was recommendations for land rehabilitation to achieve sustainable development. The

results showed that the study area with highly critical land reached an extent of 696.43 Ha or 4.48%. Critical, medium, and potentially

critical lands covered an area of 133.02 Ha or 0.85%, 80.35 Ha or 0.52 %, and 527.17 Ha, respectively. Meanwhile, uncritical land had

the largest extent, reaching 14.123 Ha. Recommendations for critical lands include vegetation and civil engineering methods.

Keywords: Mitigation, Environmental degradation, Critical land, Merapi Volcano

Introduction¹

distribution and extent of critical lands and to provide mitigation

and recommendation for land rehabilitation in the scope of

regional development according to the criticality map

Indonesia is an archipelago with 129 active volcanoes and

approximately 500 non-active volcanoes [1]. One of the most

active volcanoes in Indonesia is Merapi Volcano. Its latest

eruption in 2010 released around 100 million cubic meters of

volcanic materials [2]. Eruptions of Merapi pose disaster risks and

impacts while at the same time providing considerable economic

benefits. The positive impacts of Merapi post-eruption include

increasing soil fertility and an abundance of sand and stone

materials. The area around Merapi Volcano is a fertile region for

agriculture. A study by [3] showed that the carrying capacity of

agricultural land in disaster-prone area III of Merapi Volcano is

extremely high. Another business activity developing in the

region is sand and stone mining.

2 Material and methods

2.1 Data collection methods

Data was gathered using two methods, including: (1)

Secondary Data Collection: Secondary data was obtained from a

range of previous research, studies, and reports as well as from

the reports of related agencies and existing regional regulations.

Such method involved a literature study and institutional research;

(2) Primary Data Collection: Primary data was collected through

field observation and interview. The results consisted of

documents, interview transcripts, and location plotting from GPS.

With the course of time, sand and stone in the river become

less available, making miners expand their activity to house yards.

Mining activities become uncontrollable without regulations or

good management. Consequently, the area is prone to

environmental degradation in the form of critical land that makes

a negative impact on fertile agricultural land.

Based on the abovementioned empirical conditions, this study

is relevant to identify the criticality levels of Merapi slope regions.

As the research output, land rehabilitation is recommended to

achieve sustainable development. Identified critical level and

rehabilitation recommendation of land used Digital Soil Mapping

2.2 Data Analysis Methods

The analysis methods to determine the criticality levels,

distribution, and land area referred to the regulation from the

Directorate General of Watershed Management and Social

Forestry of the Ministry of Forestry No. P.4/V-SET/2013

concerning Technical Guidelines for Preparing Critical Land

Spatial Data. Classification of critical lands is based on the total

score of critical land parameters shown in Table 1. The following

criteria show criticality levels in agricultural land based on the

research area (Table 2). Analysis of recommendations for land

rehabilitation referred to the Government Regulation No. 76 Year

2008 concerning Forest Reclamation and Rehabilitation as well

as Regulation of Forestry Minister of the Republic of Indonesia

No. P.32/MENHUT-II/2009 concerning Guidelines for Preparing

(DSP) defined as “the creation and population of spatial soil

information systems by the use of field and laboratory

observational methods coupled with spatial and non-spatial soil

inference systems” [4]. This study aims to map and identify the

Corresponding author: Widodo Brontowiyono, Depa rtment of Environmental Engineering, Universitas Islam Indonesia (UII),

Yogyakarta, Indonesia. E-mail: widodo.bronto@uii.ac.id, lupy.algiri@gmail.com, pt.karuniakons@gmail.com.

Journal of Environmental Treatment Techniques

2020, Volume 8, Issue 3, Pages: xxx-xxx

Technical Plan of Land and Forest Rehabilitation in Watershed

Area (RTk RHL-DAS).

perspective of agriculture, critical land is associated with

production whereas the perspective of forestry correlates critical

land to its function as a medium for water management, forest

production, and protection from flood and/or downstream

sedimentation [9].

Table 1: Classification of Critical Lands Based on the Total

Score

Total Score in

Land degradation is defined as the process of temporary as

well as permanent decrease in land productivity characterized by

decreasing physical, chemical, and biological properties. Critical

land is one of the forms of land degradation [10]. In general,

critical land is among the indicators of environmental degradation

as an impact of different types of imprudent land use [11]. The

main characteristics of critical land include barrenness, aridity,

rocks emanating on the ground, and areas generally located in hilly

or steep sloping topography [12, 13]. Low productivity is

characterized by high acidity, low nutrient content (P, K, Ca, and

Mg), low cation exchange capacity, base saturation, and organic

content as well as high levels of Al and Mn that can poison plants

and are sensitive to erosion. In addition, critical land is also

generally characterized by reed vegetation with a relatively low

soil pH of 4.8 to 5.2 due to high intensity of soil washing and large

quantity of rhizomes that become mechanical barriers in plant

cultivation [14].

According to United Nations University Institute of Advanced

Studies [15], degradation of natural resources reduces the

productivity. [16] emphasized the development of high yielding

crop varieties with little attention given to the ecology on which

the plant survival. He suggested that crop yields in Africa could be

tripled through proper management of the soil environment. [17]

also reported that long-term fertilization effects on crop yield and

soil fertility changes. Studies showed that rice productivity was

strongly influenced by soil texture, nutrient concentration and

organic matter [18]. Paddy soils are naturally heterogeneous.

Complex interrelationships existing between physical, chemical

and biological soil properties have long been recognized.

Protected

Criticality

Area outside Level

Reserved

Forest Area

Cultivation

Area

the Forest

Highly

110-200

20-180

81-270

71-360

115-200

201-275

276-350

critical

201-275

276-350

Critical

Rather

Critical

Potentially

Critical

61-450

51-500

351-425

426-500

351-425

426-500

Uncritical

Literature Review

Critical land is defined as land with changes in its use and

ability that eventually endanger the hydrological function, hydro-

orological function, agricultural production, settlements, socio-

economic life, and environment [5]. Critical land is currently

unproductive land or soil due to land use and management that

does not consider the requirements of soil and water conservation,

leading to damage, loss or reduced function to predetermined or

expected limits [6].

Critical land has to be controlled due to increasing food

demand. According to Food and Agriculture Organization (FAO),

the global rice requirements in 2025 will be 800 million tons (MT)

while the present production is 600 MT and an additional 200 MT

still needs to be produced by increasing productivity per hectare to

meet the future requirements [7]. Suitable rice based cropping has

to be evaluated to assess the stability in production [8].

The definition of critical land varies between one institution

and another due to different perspectives of each user. From the

Table 2: Criteria of Criticality in Agricultural Land

Criteria (%

weight)

No.

Class

Percentage/Description

Score

Note

. Extremely High

. High

>80%

Assessed based on the

ratio to optimum

general commodity

production in a

60-80%

41-60%

21-40%

<20%

Productivity *)

3. Medium

(30)

. Low

. Extremely Low

traditional management

. Leveled

. Sloping

<8%

8-15%

16-25%

26-40%

>40%

Slope (20)

3. Medium Steep

. Steep

. Extremely Steep

. Light

0-I

III

. Medium

. Intense

. Severe

Calculated using USLE

formula

Erosion (20)

Management

-Application of soil conservation technology

. Good

Complete and in accordance with technical guidelines

- Incomplete or unmaintained

2. Average

. Poor

(30)

Not available

Journal of Environmental Treatment Techniques

2020, Volume 8, Issue 3, Pages: 988-998

Figure 1: Map of Land Use in the Research Area

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2020, Volume 8, Issue 3, Pages: xxx-xxx

Their responses along with management-induced soil changes,

like tillage, liming and fertilizer amendments result in soil

variation within cropped fields [19,20,21], and thus, as a surrogate

measure of more costly soil chemical and physical measurements

that directly affect plant growth and yield [22].

including leveled bench terrace, reverse back bench terrace,

sloping bench terrace, orchard terrace, and intermittent terrace).

Area with >40% slope gradient accompanied by signs of

landslides, including an extremely deep sand mining area, is

recommended to use the vegetative method of organic fertilizer or

permanent vegetation (Figure 6).

For critical lands in a river cliff area, rehabilitation can be

done through civil engineering with flood control and/or

riverbank protection as well as through vegetation by planting

grass. Rehabilitation of an area with slopes and signs of ravine

through civil engineering can be done by clogging ravines and

through vegetation by grass planting.

Analysis and results

According to the spatial planning of Klaten District, the

research area is intended for farming. Therefore, the identification

of critical land refers to the guidelines for agricultural land in the

Regulation of the Minister of Forestry No. P.32/Menhut-II/2009.

Factors that determine the criticality include land cover, gradient

of slope, erosion, and productivity.

Meanwhile, critical lands in a settlement area with sand

mining are recommended to use the vegetative method of grass

stripes and civil engineering method of controlling erosion and

runoff, adding soak pits/biopore holes and absorption wells, as

well as repairing drop structure drains. Kemalang Sub-district is

given the most technical recommendations, indicating the critical

condition compared to other sub-districts, including

Manisrenggo, Karangnongko, and Jatinom Sub-districts. The

Villages of Tegalmulyo, Balerante, Sidorejo and Tlogowatu are

located very near to the peak of Merapi, and these villages have

the largest number of critical lands. The path of critical lands

moves from the north to the south following the river flow, and

most of them are located along the left and right sides of the river

although some of them exist near settlements or road access.

In the Sub-district of Karangnongko, several spots of critical land

are also found, particularly in Gemampir and other villages

around. Tibayan, Temuireng, and other villages around Jatinom

Sub-district also have spots of critical land. A detailed observation

proves that the location of critical lands is either near the river or

close to road access, which is probably related to easier access to

transportation (transporting sand from the mining). Civil

engineering recommendation for the lower area is not as

challenging as for the upper area of a sub-district that must

combine several recommendations (Figure 7). Therefore,

recommendation is determined based on the critical levels.

According to the identification results, highly critical and critical

lands include fields, cemeteries, stream buffers, and moors. The

recommendations for critical land rehabilitation based on regional

spatial planning are as follows.

.1 Land Cover

Land cover was obtained from land use analysis based on the

Landsat Imagery dated 8 August 2018. Figure 1 shows the spatial

display of land use in the study area.

.2. Gradient of Slope

Spatial data of slope gradient was prepared by processing the

map of area elevations (DEM) obtained from the National

Geospatial Information Agency. The following Figure 2 shows

the elevation map of the research area.

.4 Productivity

Productivity was assessed based on the ratio to optimum

general commodity production in a traditional management. The

dominant commodities consisted of rice, corn, chili, and durian.

Data was obtained through in-depth interviews with PPL

(Agriculture Extension Agent), and the analysis result is

presented in the following map (Figure 4).

.5 Land Criticality Level

Using the four factor maps, overlay was performed to

determine land criticality. As previously described, criticality

criteria referred to agricultural production area, and the results are

as follows. The research area with highly critical lands reached an

extent of 696.43 Ha or 4.48% of the total research area. The

distribution included 24 villages in 3 sub-districts (Kemalang,

Karangnongko, and Jatinom). Critical lands had 133.02 Ha area

or 0.85% of the total research area with the distribution in 7

villages of Kemalang Sub-district. Meanwhile, 80.35 Ha or 0.52%

of the total research area had rather critical lands distributed in 23

villages of all sub-districts (Kemalang, Karangnongko,

Manisrenggo, and Jatinom). Land with potential criticality

reached 527.17 Ha or 3.39% of the total research area that covered

5 Conclusion

The research results showed that all categories of land

criticality are located in the research area with the following

detail:

1. Highly critical land has 696.43 Ha area or 4.48% of total

research area distributed in 24 villages of 3 sub-districts.

2. Critical land is 133.02 Ha in extent or 0.85% of total research

area located in 7 villages of Kemalang Sub-district.

3. Rather critical land has 80.35 Ha area or 0.52% of the total

research area spread in 23 villages of all sub-districts.

villages in 2 sub-districts (Kemalang and Karangnongko).

Finally, the uncritical lands had the largest extent, reaching

4.123 Ha or 90.77% of the total research area covering 61

villages in all sub-districts. The spatial map is presented in Figure

Potentially critical land reaches an extent of 527.17 Ha or

3.39% of total research area covering 6 villages in 2 sub-

districts.

.3 Erosion Hazard Level

Erosion Hazard Level is normally calculated by comparing

the erosion level of a land unit with its effective soil depth. In this

case, erosion level was calculated by assessing average annual

soil loss due to sheet erosion and rill erosion using Universal Soil

Loss Equation (USLE) formula (Figure 3).

5. Uncritical land has the largest area with 14.123 Ha or 90.77%

of total research area distributed in 61 villages of all sub-

districts.

Critical land rehabilitation through civil engineering and

vegetation methods can be recommended. In general, the selected

vegetation should optimize the available in-situ vegetation while

the recommended civil engineering method is the terracing

system (bench terrace, including leveled bench terrace, reverse

back bench terrace, sloping bench terrace, orchard terrace, and

intermittent terrace).

.6 Recommendation for Land Rehabilitation

It is recommended that the aforementioned critical lands be

given rehabilitation through vegetation and civil engineering. In

general, the choice of vegetation is expected to originate from the

existing in-situ vegetation while civil engineering general

recommendations can use the terracing system (bench terrace,

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2020, Volume 8, Issue 3, Pages: 988-998

Figure 2: Map of Slope Gradient of the Research Area

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Figure 3: Map of Soil Erosion in the Research Area

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2020, Volume 8, Issue 3, Pages: 988-998

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Figure 4: Map of Productivity in the Research Area

Figure 5: Map of Land Criticality in the Research Area

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2020, Volume 8, Issue 3, Pages: 988-998

Figure 6: Map of Recommendations for Land Rehabilitation Using Vegetative Methods

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2020, Volume 8, Issue 3, Pages: xxx-xxx

Figure 7: Map of Recommendations for Land Rehabilitation Using Civil Engineering Methods

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2020, Volume 8, Issue 3, Pages: 988-998

Table 3: Recommendation for Critical Land Rehabilitation

Spatial Plan

Field

Recommendation

Migrate to or search for uncritical lands

Cemetery

Migrate to (by considering local socio-cultural condition) or search for uncritical lands

Return stream buffers to their function as river protection. In a river without embankments, the distance of 3-20

meters can only be used for bridges, gas pipes, and power cables. Other constructions, including residential buildings

or business sites (such as sand mining) are forbidden. In the area of former extremely deep sand mining (>40m)

terraces can be built for easier access downwards as well as for soil and water conservation. Vetiver grass can be

planted at the initial stage, and when the environmental condition has improved, other vegetation with high economic

benefits can be introduced, such as corn and chili intercropped with perennials, for example durian, jackfruit, or

avocado.

Stream buffer

In general, suitable seasonal plants with a dense crown and economic value can be selected, terracing can be built,

and planting surrounding the slope can be done. From highly critical lands, several characteristics will appear, for

example, the presence of river cliffs and ravines for which vegetative recommendation can be executed by planting

grass, and in potential landslide area, the vegetative recommendation is the use of organic fertilizers, permanent

vegetation including industrial plants, plantation, protected forest park, community forests, reserved forests, and

tourism forests. Meanwhile, the civil engineering recommendations can be done by constructing river embankments,

clogging ravines, (or if possible, ravines can be turned into reservoirs for irrigation water reserves during the dry

season). The area of former extremely deep sand mining (>40m) can be given terraces for easier downward access

and also for conservation of soil and water. At the initial stage, Vetiver grass can be planted, and for improved

environmental condition, other vegetation of high economic value can also be planted, such as corn and chili

intercropped with perennials, such as durian, jackfruit, or avocado.

Moor

Vegetative recommendation for an area with >40% slope

gradient and signs of landslides, such as extremely deep sand

mining area, is the use of organic fertilizer and permanent

vegetation.

Penerapan Teknologi (Mineral Resources Technology Center- Board

for Technology Research and Implementation). Jakarta. 2008

Prawira, A.Y., Wikantika, K. and Hadi, F. Analisis Lahan Kritis di

Kota Bandung Utara Menggunakan Open Source GRASS (Bandung

Critical Land Analysis by Using GRASS), Proceeding PIT MAPIN

XIV. Bogor. 2005

Herdiana, D. Identifikasi Lahan Kritis dalam Kaitannya dengan

Penataan Ruang dan Kegiatan Rehabilitasi Lahan di Kabupaten

Sumedang (Critical Land Analysis related to Spatial Planning in

Sumedang). Unpublished Thesis. Sekolah Pasca Sarjana Institut

Pertanian Bogor (Bogor Agriculture University). Bogor. 2008

Aknowledgment

It is appreciated to the Environmental and Forestry Agency of

Klaten District for supporting the research.

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