Identification and Mapping of Prone to Landslide in the Sub District of Kintamani, Bali Province, Indonesia
Abstract
This research was conducted in several locations of prone to landslides in the Sub District of Kintamani, Bangli Regency, Bali Province, Indonesia. Determining the research location is purposively, meaning intentionally determined by observing in the field to landslides during the rainy season 2016/2017. The purpose of research, namely: (1) identifying areas prone to landslides at several locations in the Sub District of Kintamani, Bangli Regency; (2) to mapping areas prone to landslides using geographical information systems (GIS), (3) to formulate the strategies to overcome landslides. The analytical method used is descriptive -qualitative, meaning that the results of field observations and interviews integrated and interpreted in a narrative -qualitative. R esults of the analysis showed that the location is prone to landslides in the sub district of Kintamani are Villages of Selulung, Satra, Tanah Gambir, Tegallinggah, Pinggan, Songan, Kayu Selem, Blancan, Batur, Bubung Kelambu, Pura Tanah Mas, Mampeh, Yeh Mampeh, dan Penelokan, with total area of 144,36 ha.
The cause of landslides are high rainfall, soil type regosol, geology, slope average above 15% and the use of land that is no t paying more attention on land conservation. Further mapping of landslide -prone locations using Q -GIS and Google Earth.
Strategies to overcome landslides is to avoid the cultivation of agriculture in areas prone to landslides, implement agroforestry systems, planting cover crops, making sewers or ditches, enforcing the rules of the spatial region and violators are given strict and severe sanctions.
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Introduction
Indonesia, including Bali as a one of Province in Indonesia is an area prone to natural disasters, caused by over -exploitation of natural resources, land conversion, improper land use, and global climate change such as the prolonged rainy season in 2016/2017. Natural disasters can occur suddenly or slowly, earthquakes, tsunamis and volcanoes are almost impossible to estimate accur ately, when will happen and how much strength. While floods, landslides, droughts are predictable. In the rainy season there are two disaster threats namely floods and landslides. Floods and landslides occasionally occur respectively. Continuous floods wil l erode the land slopes of hills or mountains, so if the construction of the soil is unstable it will happen ed landslide.
Bali's concerns were struck by the disaster as Lanina's impact during the rainy season of December 2016 to February 2017, becoming a r eality; this is all due to Bali's nature already damaged from upstream to downstream. For example in sub district of Kintamani this year experienced the worst natural disaster during 20 years. The team from the Geological Agency has checked into the field, the Banjar of Bantas area in the middle of the hill of Kintamani is now in a vulnerable condition, due to the landslide that is easily landslide (Bali Post, 2017).
Suripin (2002) and Anwar, et al. (2003) stated that landslides are a form of erosion where the transport or movement of the soil mass occurs at one day in a relatively large volume. Mass that moves in the landslide is a large mass, so often the occurrence of landslides will bring the victim in the form of environmental damage, degradation of agr icultural land, settlements damage and damage of infra structure and property and even the loss of human life. Landslides constitute the movement of slope -forming materials in the form of rocks, rickwheels, soils, or mixtures of such material moving down o r out of the slopes. The process of occurrence of landslides starting from water that seep into the soil will increase the weig ht of the soil. If the water penetrates to the impermeable soil that acts as a slip plane, it will become slippery and the weath ering soils on it will move along the slope and out of the slope. In principle, landslides occur if the driving force on the slope is greater than the retaining force. Retaining force is generally influenced by rock strength and soil density, whereas the dr iving force is usually influenced by the amount of inclination angle of the slope, water, load and soil type of rock. The causing factors the movement of the slope also depend on the conditions of rock and slope soil, geological structure, rainfall, cover of vegetation and land use on the slop .
Page | 60 The potential for landslide disaster in Bali Province is 85,121,55 ha, and one of the regency prone to landslide is Bangli Regency. Some of the villages in sub district of Kintamani, Bangli regency are landslide -prone areas, because they are on steep slopes, especially in the upper reaches where the soil is dominated by sandy texture, has a high rainfall of about 2000 mm per day, so when it rains with high intensity and long, prone to landslide disaster (Bappeda Bali and PPLH Unud, 2006).
The cause of landslide and its prevention is very important to know, so that it can minimize the occurrence of landslide and the resulting consequences (Law Number 24 Year 2007 on Disaster Management). So the disaster management plan is a manifestation of government efforts related to the formulation of activity programs and the focus of the priority of disaster management, then the characteristics of the disaster must be studied carefully.
Based on the previous description, the object ives of the research are: (1) to identify the affected areas and prone to landslide disaster in the sub district of Kintamani, Bangli regency, Bali Province, (2) to mapping the landslide prone area by using geographic information system (GIS); (3) formulat e the strategies used to overcome the risk of landslide disaster.
Conclusion
4.1 Conclusions 1. Based on observation and field identification, landslide disaster in sub district of Kintamani occurred in some vullages i.e. Selulung, Satra, Tanah Gambir, Tegallinggah, Pinggan, Songan, Kayu Selem, Blancan, Batur Bubung Kelambu, Pura Tanah Mas, Mampeh, Y eh Mampeh and Penelokan with Extent 144,36 ha. The factors that cause landslide disaster are: rainfall, geological structure, soil type, slope inclination, land use that does not pay attention to the rules of land conservation. 2. Mapping is based on fiel d observations using GPS equipment combined with interviews with communities around the disaster site resulting in a Q -GIS-based digital map as presented in Figure 2. 3. Strategy to overcome landslides is to prohibit development in areas prone to landslide di saster, cover the land with agroforestry systems, create drainage ditches or ditches, and rules should be enforced and those who violate severe sanctions. 4.2 Recommendation Avoiding or reducing the landslide disaster in the research area, stakeholders such as communities around in Sub District of Kintamani and Regional Governments should implement the strategies which formulated in this study .
