1st Conference On Engineering, Technology And Education 2016 (CETEd2016), Politeknik Merlimau Melaka 4-5th October 2016 APPLICATION OF GEOGRAPHICAL INFORMATION SYSTEM (GIS) FOR LANDSLIDES RISK MAPPING IN BATU PAHAT Suhaiza1* S., Masiri2 K., Ismail3 S.N.S., Kamsir4 S.J.M. 1, 3Department of Civil Engineering Politeknik Merlimau Melaka, Karung Berkunci 1031, Pejabat Pos Merlimau, 77300 Merlimau Melaka, Malaysia. 2,4 Pusat Pengajian Diploma, Universiti Tun Hussein Onn Malaysia, Batu Pahat, Johor, Malaysia. *[email protected] ABSTRACT Landslide or slope failure occur when the particle of soils or rocks are not stable and also because of several factors; water, wind, weather or temperature changes and human activity. Geographical Information System (GIS) is used for capturing, storing, analyzing, managing and presenting data which is spatially referenced (linked to location). There are eight factors can be taken into account to predict landslide condition such as rainfall, drainage, types of soil, slope, groundwater, land use, soil erosion and mineral. This study used several types of maps such as contour, slope, rainfall distribution, type of soil, land use and height map in order to produce a risk map for landslides at Batu Pahat area. By using ArcView Ver 3.2 software, landslide’s risk map was produced to identify the critical area. Keywords: Geographical Information System (GIS), landslides 1.0 INTRODUCTION Landslide is one of the major hazards that cause losses of lives and properties which require com plex analyses involving multitude of factors. Landslide will occurred when the movement of soil from highland to flat area interact with the gravity force. Landslides phenomena involve two major factors which are human activities and natural process (Fatimah Shafinaz, 2005). Nowadays, the landslide rarely occurs, but it can be menace to the community especially to the residents who live down the hill. The characteristics and structure of soil are very important in development proposed area in order to avoid landslides occurrences. The objective of this study is to apply the GIS technique in producing a risk map of landslides area. The efficiency of GIS usage was confirmed by the yield of risk map. GIS has been used in this study to determine the potential of locations landslide in Batu Pahat. The advantages of GIS can be determined by presenting the location effectively, faster and inexpensive (George, N 1996). ArcView software was selected to produce GIS data into the excellent outcome. 2.0 METHODOLOGY 2.1 Data Collection Batu Pahat in Johor (shown in Figure 1) was selected as the location of study because it consists of a combination of various landforms, hydrological and soil characteristics. The total area of study is about 196,041 hectares; the land is mainly generally flat and except at the western and northern part has an undulating terrain such as prominent hills. The spatial data on land use, contour, soil, and type of soil maps were provided by Faculty of Civil and Environmental Engineering (FKAAS) of Universiti Tun Hussien Onn Malaysia (UTHM), rainfall data gathered from Department of Irrigation and Drainage, and the data related to groundwater and soil erosion were gathered from previous researchers. 245 245 245 1st Conference On Engineering, Technology And Education 2016 (CETEd2016), Politeknik Merlimau Melaka 4-5th October 2016 Figure 1: Study area 2.2 Analytical Methods This study was referred to Fatimah Shafinaz Ahmad (2005) research in producing risk mapping in Penang. The methodology of research used the combination of USLE method, GIS application and landslide cases in Malaysia. As the result, landslide risk map for Penang show ed the high to low risk area. Bukit Saujana at Paya Terubung has been located as the high risk area and has been proven by the landslide case in 28 November 1998. The study also used eight factors in predicting landslide condition such as rainfall, drainage, types of soil, slope, groundwater, land use, soil erosion and mineral. USLE Method ULSE method was introduced by Wischmeier (1978). Research has been done to the Rocky Mountains began in the late 1950s. However, this method has been updated from time to time. USLE method is used to determine the soil erosion that inserted into GIS software to evaluate the potential area of landslide. There are six parameters involved in this equation; A = R × K × L × S × C × P (1) Where; A = total of soil erosion of soil (tonne / ha / year) R = rainfall factor K = erosion factor namely texture, organic matter percentage, structure and impact for crop L = length slope S = gradient slope C = plant factor and management P = soil characteristic namely terrace, contour, etc 2.3 Determination of Weightage A weight represents the relative importance of a parameter. Weightage index overlay method takes into consideration the relative importance of the parameters and the classes belonging to each parameter. There is no standard scale for a simple weightage overlay method, thus criteria for the analysis of each parameter should be defined and should be given priority. This weight is given by spatial data category by its stability which are stable, moderate and not stable as 0, 1 and 2 respectively. The finalized weights for respective thematic layers (shown in Table 1 to Table 8) were inserted into the GIS database accordingly at this stage before proceeding to the task of integration of layers. 246 246 246 1st Conference On Engineering, Technology And Education 2016 (CETEd2016), Politeknik Merlimau Melaka 4-5th October 2016 Table 1: Weights for Rainfall (Tew, 1999) Table 4: Weights for Land Use (Erny, 2008) Land Use Stability Weight Annual Rainfall Stability Weight 1500-1867 mm Stable 0 Forest Area Not Stable 0 Agriculture Area Moderate 1 1868-2235 mm Moderate 1 Shrub Area Moderate 1 2236-2600 mm Not Stable 2 Swamp Area Not Stable 2 Table 2: Weights for Type of Soil (Tew, 1999) Town Area Moderate 1 Commodious Area Not Stable 2 Types of Soil Stability Weight Catchments Area Not Stable 2 Air Stable 0 Table 5 : Weights for Mineral (Fatimah, 2005) Batu Anam-Durian Stable 0 Mineral Stability Weight Batu Anam-Malacca-Tavy Moderate 1 Briah-Organic Clay and Muck Stable 0 Granite Stable 0 Bungor-Munchong Stable 0 Alluvium (clay) Moderate 1 Durian-Malacca-Tavy Moderate 1 Sedimentary Moderate 1 Gajah Mati-Munchong Volcanic Stable 0 Stable 2 Malacca Conglomerate Moderate 1 Holyrood-Lunas Moderate 1 Alluvium (sand) Not Stable 2 Keranji Stable 0 Kulai-Yong Peng Stable 0 Table 6: Weights for Drainage (Fatimah, 2005) Organic Clay and Muck Stable 0 Value A Stability Weight (tone/ha/year) Peat Stable 0 0-0.05 Stable 0 Prang Stable 0 0.2-3.664 Moderate 1 Renggam-Jerangau Moderate 1 4-16 Not Stable 2 Sedu-Pt. Botak-Linau Moderate 1 Segamat-Katong Stable 0 Table 7: Weights for Soil Erosion (Erny, 2008) Serdang-Bungor-Munchong Moderate 1 Buffering zone Stability Weight Steepland Not Stable 2 Telemong-Akob-Local No buffering Stable 0 Moderate 1 Alluvium Buffering zone at 100m Moderate 1 Urban Land Moderate 1 Buffering zone at 50m Not Stable 2 Table 3: Weights for Slope (Morgan, 1986) Table 8: Weights for Groundwater Content (Wong, 2006) Slope Steepness Stability Weight < 12° Stable 0 Groundwater Content Stability Weight (gallon/hr) 13° - 35° Moderate 1 191-241 Stable 0 > 35° Not Stable 2 242-292 Moderate 1 293-342 Not Stable 2 247 247 247 1st Conference On Engineering, Technology And Education 2016 (CETEd2016), Politeknik Merlimau Melaka 4-5th October 2016 3.0 RESULT AND DISCUSSION All thematic layers with properly assigned weights were combined with ArcView GIS 3.2 software. According Table 9, all base maps were combined in first and second processes to produce the landslide risk map. Data in Table 1 to Table 8 were contributed in the landslide attribute data. The total weightage were classified into four groups i.e. high risk (14-16), moderate high risk (8-13), moderate (4-7) and low risk (0-3) (Table 10). Table 9: Flow of Integration Process First Secon d Name of Map Base map Final Process Process Rainfall Slope Land Use Type Of oil Soil Erosi o n Ground water Content Mineral Drainag e Table 10: Total Weightage Moderate Moderate Category High risk Low Risk High Risk Risk Max Min Max Min Max Min Max Min Rainfall 2 2 2 1 1 1 1 0 Drainage 2 2 2 1 1 1 1 Types of 2 2 2 1 1 1 1 0 Soil Slope 2 2 2 1 1 1 0 0 Groundwater 2 2 2 1 1 1 0 0 Land Use 2 2 1 1 1 0 0 0 Erosion 2 1 1 1 1 0 0 0 Mineral 2 1 1 1 0 0 0 0 Total 16 14 13 8 7 4 3 0 From the result, the landslide risk condition was presented by red colour. The dark red colour shows the high risk area, while the lower risk area with a lighter red color. There is no high risks area in Batu Pahat but 33% and 57% of area are located at moderate high risk and moderate risk respectively. Almost of the moderate high risk area was located at the Nothern part of Batu Pahat. It is because topography of Batu Pahat is mainly plane or flat except at the western and northern parts which have an undulating terrain such as prominent hills. 248 248 248 1st Conference On Engineering, Technology And Education 2016 (CETEd2016), Politeknik Merlimau Melaka 4-5th October 2016 The risk area can be changing into another condition from time to time, i.e low to moderate risk area by another factors such as climate changes, land use of area etc.