A Journal of Radix International Educational and Research Consortium RIJSS RADIX INTERNATIONAL JOURNAL OF RESEARCH IN SOCIAL SCIENCE SUITABLE SITE DETERMINATION FOR URBAN SOLID WASTE DISPOSAL, USING GIS AND REMOTE SENSING TECHNIQUES IN GONDAR CITY, ETHIOPIA. ABEL MARKOS Lecturer, Department of Geography & Environmental Studies College of Social Sciences and Humanities University of Gondar, Ethiopia. EBRAHIM ESA Lecturer, Department of Geography & Environmental Studies College of Social Sciences and Humanities, University of Gondar, Ethiopia. ABSTRACT Solid waste management is a global environmental problem in today s world. There is an increase in commercial, residential and infrastructure development due to the population growth and this has negative impact on the environment. Urban solid waste management is considered as one of the most serious environmental problems confronting municipal authorities in developing countries. Land filling is a common method of waste disposal in Ethiopia. Recently, due to an increase in the awareness of environmental risks from landfills, there has been a movement towards the selection of new solid waste disposal sites for the city, however the methodology they applied didn t incorporate remote sensing and GIS techniques These days in order to solve environmental problem, a multi criteria analysis approach using remote sensing and GIS are applying and become successful. GIS can be used to convert geo-referenced data into computerized maps and map analysis tools can be used to manipulate maps in an efficient way. One of these impacts is due to location of dumping site in unsuitable areas. This paper deals with determination of suitable site for the disposal of urban solid waste generated from Gondar city and surrounding areas using GIS techniques. Multi criteria techniques were used to determine the suitable site for new disposal. The basic factors that used for the determination of the suitable area are land use, slope, distance from river and distance from road. GPS field sampling and remote sensing technique was used to generate the data. Hence, the potential most suitable areas for solid waste dumping sites fall on southern part of the town where there are least environmental and health risks. The GIS and remote sensing 1 P a g e www.rierc.org
techniques are important tools for solid waste site selection. Hence, the capacity to use GIS and remote sensing technology for the effective identification of suitable solid waste dumping site will minimize the environmental risk and human health problems. Keywords: GIS, Remote Sensing, Solid waste management 1. INTRODUCTION Waste is a material discharged and discarded from each stage of daily human life activities, which leads to adverse impacts on human health and the environment (Bringi, 2007); whereas, solid waste refers to the leaves/ twinges, food remnants, paper/cartons, textile materials, bones, ash/dust/stones, dead animals, human and ani-mal excreta, construction and demolishing debris, biome-dical debris, household hardware (electrical appliances, furniture, etc) (Sha Ato et al., 2007; Babatunde et al., 2013). Increasing population, the rapid economic growth and the rise in community living standards accelerate municipal solid waste (MSW) generation in developing cities. Municipal solid waste management (MSWM) is one of the critical environmental challenges of rapid urban development facing the developing countries including Ethiopia. Solid waste arising from human domestic, social and industrial activities are increasing in quantity and variety as a result of growing population, rising standards of living and development of technology (Suess, 1985; UNEP, 1991; Dickerson, 1999). A decade ago, Beede and Bloom (1994) estimated the global MSW generation rate at 1.3 billion tons per day; translated to an average of two-thirds of a kilogram per capita per day or ten times per capita body weight per year. According to a United Nations Development Programme survey of 151 mayors of cities from around the world, the second most serious problem that city dwellers face (after unemployment) is insufficient solid waste disposal (UNDP, 1997). One of the major problems in waste management is concerned with the selection of appropriate site for the waste disposal. The efficacy of solid waste disposal depends upon selection of proper site and there are several issues that have impact for site selection. Broadly they are divided into three categories i.e. Economic, Social and Environmental. Previous studies have reported several techniques for suitable site selection, which can be found in the literature (Halvadakis, 1993; Bonham-Carter, 1994; Ehler et al., 1995; Balis et al., 1998; Dorhofer and Siebert, 1998; Yagoub and Buyong, 1998; Herzog, 1999; Lukasheh et al., 2001). Surveys such as that conducted by Charnpratheep et al. (1997), Kao et al. (1997) and Sener et al. (2006) have shown that Geographic information system (GIS) is a digital database management system designed to manage large volumes of spatially distributed data from a variety of sources. They are ideal for advanced site-selection studies because they efficiently store, retrieve, analyze, and display information according to user-defined specifications. GIS has been extensively used to facilitate and lower the cost of the landfill site selection process. Several studies have revealed that other sitting techniques combine multiple criteria analysis with GIS (Minor and Jacobs, 1994; Kao and Lin, 1996; Lin and Kao, 1998; Allen et al., 2002; Kontos and Halvadakis, 2002). They also stated that these techniques are used to evaluate the sitting suitability for the entire study region based on a suitability index. Erkut and Moran(1991) have developed analytical hierarchy process (AHP) is a decision-making technique which can be used to analyze and support decisions which have multiple and even competing objectives. To do this, a complex problem is divided into a number of simpler problems in the form of a decision hierarchy. Accordingly once the hierarchy had been established, a pair wise comparison matrix of each element within each level is 2 P a g e www.rierc.org
constructed and participants can also weigh each element against each other within each level, which is related to the levels above and below it and mathematically tie the entire scheme together and also numerous studies have attempted to explain that the suitable site sitting problems using GIS and multicriteria analysis or intelligent system approaches in Greece, Turkey, and Jordan (Vatalis and Manoliadis, 2002; Kontos et al., 2005; Al-Jarrah and Abu-Qdais, 2005; Sener et al., 2006). Like other rapidly developing cities, Gondar also has bigger Solid waste disposal problem. As stated above, one of the major problems in waste management is concerned with the selection of appropriate site for the waste disposal. The efficacy of solid waste disposal depends upon selection of proper site and there are several issues that have impact for site selection. Broadly they are divided into three categories i.e. Economic, Social and Environmental. The ultimate aim is to select a site where the greatest protection of the environment is provided. Site selection is a part of environmental planning, where the principal part is of problem to select Landscape that is functional safe. 2. DESCRIPTION OF THE STUDY AREA Gonder is located in North Gondar Zone, Amhara National regional State (ANRS). It is one of the 24 weredas in the zone out of which four are city administrations (Gonder, Gendawuha, Ayekel and Debark towns) and the rest 20 are rural werdas. It is also one of the three metropolitan cities in the region along with Bahirdar and Dessie. The astronomical location of the town is 12º45 North latitude and 37º45 East longitude. The town is found at a distance of 737km from Addis Ababa and 175 km from Bahirdar the regional capital, and 250 km from Gedarif the Sudanese border town. It is situated at strategic location linking highly productive cash crop commercial areas, historical and tourist sites. Figure1. Location map of the study area 3 P a g e www.rierc.org
2.1.2 TOPOGRAPHY Gonder is located in the northern highlands of Ethiopia. The topography of the town is undulating and consists of hills, sloppy areas, gentle slope areas, rivers and streams. The elevation of the town ranges between 1850-2752.5m above sea level. Elevation of the town decreases from north to the south and then rises again in the eastern part of Teda town. 2.2 POPULATION As indicated in the table, the population of Gondar was 36309, 41788, 67790 and 80675 in 1967, 1970, 1978 and 1984 respectively. The population of the town was 119530, 206987 and 306246 in the year 1994, 2007 and 2014 respectively. However; according to CSA, the town s population was 265,000 in 2013. Population of the rural kebele was 46464 in 2012 and 48694 in 2013. Therefore, considering the previous data of rural population and the growth rate by taking the population of the town for the period of 2012-13 was 4.8%, assuming that the rural pollution will increase with the same rate the rural population is therefore 51032 in 2014. Based on these, the total population of Gondar town including that of the rural kebeles and Teda town in 2014 is 306246 plus 51032 which is equal to 357,278. Table: 1. Population size and sex ratio of Gondar city Year Male Female Total Sex ratio 1967 15280 21029 36309 72.7 1970 16760 25028 41788 67.0 1978 27789 40002 67790 69.5 1984 34513 46162 80675 74.6 1994 52143 67387 119530 77.0 2007 98085 108902 206987 90.1 2014 149970 156276 306246 96.0 3. MATERIALS AND METHODS Source: CSA reports. Both primary and secondary data were used in the study. The primary data were collected from field surveys and observation. Whereas, the secondary data for the study was acquired from internet, reports, books, journals, governmental institutions and other documents. The main data used for this study is landsat satellite image of the town with spatial resolution of 30 m and DEM(Digital Elevation model). 4 P a g e www.rierc.org
Pre processing operations such as radiometric, image restoration and rectification were applied in order to enhance the analysis of the image. The study used spatial multi-criteria analysis technique to identify the most suitable solid waste site. Spatial multi-criteria approaches (SMCA) have the potential to reduce the costs and time involved in siting facilities by narrowing down the potential choices based on predefined criteria and weights and permitting sensitivity analysis of the results from these procedures (Higgs, 2006). The solid waste disposal site selection mapping was done using multi criteria evaluation and creating layers to yield a single output map or index of evaluation (Wiley and Sons, 2009). The weights were developed by providing a series of pair wise comparisons of the relative important factors to the suitability of pixels for the activity being evaluated. The procedure by which the weights were produced follows the logic developed by Saaty (1977) under the analytical hierarchy process (AHP) which is utilized to determine the relative importance of the criteria in a specified decision-making problem. Linear distances were derived for each factor at maximum size for the purpose of classification. 3.1 METHODOLOGY. Figure2. Schematic representations of Methodology. 5 P a g e www.rierc.org
4. RESULTS AND DISCUSSION 4.1 SUITABILITY OF LAND USE/LAND COVER Landsat satellite image of the year 2014 were used to develop the land use land cover map of the city. The image was classified in to different class using both supervised and unsupervised approache. The major landuse classes were settlement, water body, bare land, grass land and agricultural land. By reviewing different literature it was advisable to select land, which was occupied by bare and grass lands for solid waste disposal. Figure3 Land use land cover map of the Study Area. Table 2: Suitability score given for landuse Type of landuse Suitability score Level of suitability Settlement 3 Less suitable 6 P a g e www.rierc.org
Grass land 2 Moderate suitable Bare land 1 Most suitable Water body 4 Unsuitable 4.2 SUITABILITY DISTANCE FROM RIVERS The farther lands from river banks got more preferences for solid waste dumping site suitability. Euclidean distance tool of the spatial analysis was used in order to identify which area is suitable for the waste disposal area. The Euclidean distance functionality of the ArcGIS calculates Euclidean distance from each cell. Figure 4 Reclassified distance from river Table 3: Suitability score given for Distance from rivers Distance from rivers Suitability score Level of suitability 0-500 4 Unsuitable 500-1000 3 Less suitable 1000-1500 2 Moderate suitable >1500 1 Most suitable 7 P a g e www.rierc.org
4.3 SUITABLE DISTANCE FROM MAIN ROADS TO SOLID WASTE DUMPING SITE As the general concept, the landfills shall not be located within 100 m of any major highways, city streets or other transportation routes. Solid waste dumping site must be located at suitable distance from roads network in order to facilitate transportation and consequently to reduce relative costs. The study preferred a buffer of 2000 m distance from main roads by referring to different sources. It was reclassified as unsuitable road within 500 m, low suitable between distances from 500 to 1000 m. The distance starting from 1000 up to 1500 was consi-dered as moderate suitable and highly suitable is dis-tance between 1500-2000 m. Figure 5. Reclassified distance from major roads Table 4: Suitability score given for Distance from major roads Distance from major roads Suitability score Level of suitability 500-1000 4 Unsuitable 1000-1500 3 Less suitable 1500-2000 2 Moderate suitable 2000-2500 1 Most suitable 8 P a g e www.rierc.org
4.4 SUITABILITY OF SLOPE This study considered the lower slope more highly suitable than the land with higher slope. Different research shows that areas with high slopes will have high risk of pollution and potentially not a good site for dumping. Figure 6 Reclassified slope map Table 5: Suitability score given for slope Slope in degree Suitability score Level of suitability 75-78 4 Unsuitable 62-75 3 Less suitable 42-62 2 Moderate suitable 0-42 1 Most suitable After projection and topology creation all feature classes like land use, slope, drainage, stream, and road were converted to raster files and separate datasets were created using weightage and rank. For the analysis all the raster datasets for different layers having different score were over layed and the scores of 9 P a g e www.rierc.org
each composite class were added using raster calculator tool of spatial analyst extension of Arc Map. The final scores were reclassified to generate the output map showing various classes of suitable site for waste dumping. The decision rules for finding suitable land area are given in the table. Criteria Table 6: Decision rules for finding suitable Land area. Suitability class Highly Suitable Moderately suitable Less Suitable Land use Bare land Grass land Settlement and water body Distance from rivers in meter >1500 1000-1500 0-500 Distance from Major road in meter >2000 1500-2000 500-1000 Slope 0-42 42-62 >62 5. SUMMERY AND CONCLUSIONS Remote sensing and GIS has been used in this project for the selection of suitable site for waste disposal. And this is best technique than other technique even if minimize cost and time that utilize for the project. The findings have shown the ability of GIS and remote sensing as a veritable tool for analyzing the criteria for decision support. The analysis has taken land use, slope, distance from main rivers, and distance from major roads for solid waste dumping site. The results have shown that one site was selected as the most suitable. The site is easy to access; manage for disposal of solid wastes. Therefore this research has outlined a method on the selection of suitable site for solid waste disposal related criteria adopted from different researches. The potential most suitable areas for solid waste dumping sites fall on southern part of the town where there are least environmental and health risks. The GIS and remote sensing techniques are important tools for solid waste site selection. Hence, the capacity to use GIS and remote sensing technology for the effective identification of suitable solid waste dumping site will minimize the environmental risk and human health problems. 10 P a g e www.rierc.org
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