Development of ranking criteria for assessment of existing and proposed solid waste dumping sites in Faisalabad, Pakistan with the help of remote sensing and GIS techniques.

Abstract

Priority wise channelization of resources is the key to successful environmental management, especially when remedial resources are limited. The study in hand has successfully explored potential of Remote Sensing (RS) and Geographic Information System (GIS) techniques for assessing environmental impacts of Municipal Solid Waste (MSW) open dumps. An additional emphasis in this regard was to compare different MSW open dumps for their environmental hazards. The study was mainly done for MSW open dumps of Faisalabad, but for comparison MSW dumps of Lahore have also been incorporated. This study can be divided into the development of an algorithmic criterion that compares MSW dumping sites as a whole, establishing use of the remotely sensed satellite data for detailed bio-thermal hazards assessment of MSW dumps, to study impact of varying geography on these affects, and to study spectral behavior of MSW open dumps for their possible identification. It is first study of its kind that have modeled economical methods within the framework of remote sensing and spatial analysis that can be easily adopted in developing world. The developed ranking algorithm is a Multi Criteria Analysis (MCA) that has made use of the scaling function, to normalize the data values, Analytical Hierarchy Process (AHP) for assigning weights to input parameters showing their relevant importance and Weighted Linear Combination (WLC) for aggregating the normalized scores. Input parameters for this algorithm have been divided into three classes namely resident's concerns, groundwater vulnerability and surface facilities. Remote Sensing data and GIS analyses were used to prepare most of the input data. Working of the algorithm has been elaborated by comparing four of the dump sites namely main Municipal Solid Waste Open Dump (MSWOD) of Faisalabad (MF-MSWOD), new MSWOD of Faisalabad (NF-MSWOD), Saggian and Mahmood Booti (MB-MSWOD) dumps of Lahore. The comparison has been made first at class levels and then class scores have been aggregated into environmental normalized index for environmental impact ranking. The hierarchy of goodness for the selected sites is found to be NF-MSWOD > MF-MSWOD > MB-MSWOD > Saggian with comparative scores of goodness to environment as 36.67, 28.43, 21.26 and 13.63 respectively. Flexibility of developed criteria to adjust any number of classes and parameters in one class will be very helpful for developing world where availability of data is the biggest hurdle in research based environmental sustainability planning. The proposed model can be run even without 2 purchasing expensive satellite data and GIS software, with little inaccuracy, using imagery and measurement tools provided by Google Earth. To establish the use of the remotely sensed satellite data for detailed bio-thermal hazards assessment of MSW dumps thirty images of Landsat-8 have been selected after validation for the accuracy of their observational details from April, 2013 to October, 2015. Land Surface Temperature (LST), Normalized Difference Vegetation Index (NDVI), Soil Adjusted Vegetation Index (SAVI) and Modified Soil Adjusted Vegetation Index (MSAVI) derived from these images through Digital Image Processing (DIP) and have been used for spatio-temporal analysis in GIS environment. MF-MSWOD has been found with average temperature elevation of 4.3 K and 2.78 K from nearby agriculture land and urban settlement respectively. Vegetation health has been used as the bio-indicator of MSW effects and is implemented through NDVI, SAVI, MSAVI. Spatial analyses have been used to mark boundary of bio-thermally affected zone around dumped MSW and measures 700 m. Seasonal fluctuations of elevated temperatures and boundary of the biothermally affected zones have also been discussed. Based on the direct relation found between vegetation vigor and the level of deterioration within the bio-thermally affected region, use of crops with heavy vigor is recommended to study MSW hazard influence using bio-indicators of vegetation health. The results obtained and the research methodology of spatial analysis for MF-MSWOD, surrounded by a uniform vegetation cover all around, have been compared with that of the MBMSWOD surrounded by a complex neighboring land cover. Contrary to MF-MSWOD, the MBMSWOD has been found to affect surrounding vegetation to an average distance of about 650 m that varies from 400 m in winter to 800 m in dry summer. The thermal influence zone was observed to have about the same radial extent of 650 m with minimum of 350 m found in dry summer and maximum of 1000 m in winter. The comparison has resulted into two main conclusions. In the first place the severity of bio-thermal effects of an open MSW dump, in addition to waste age, characterization, pile etc., also depends on surrounding geography. Secondly, the use of GIS analysis for studying the bio-thermal effects requires modification that varies from case to case, depending upon neighboring land cover. The use of remotely sensed data for monitoring dumped MSW is a good alternative but selection of proper GIS methodology, representing natural setting of phenomena is as important as accuracy of the remotely sensed data.