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Spotting noise risk zones in Karachi Pakistan : A GIS Perspective Mohammed Raza Mehdi Institute of Environmental Studies, University of Karachi & Department of Civil Engineering, NED University of Engineering & Technology, Karachi Dr. S. Jamil Hasan Kazmi Assistant Professor Department of Geography, University of Karachi and Mudassar Hassan Arsalan Department of Geography, University of Karachi. ABSTRACT In developing countries such as Pakistan the growth of their megacities such as Karachi had been unplanned and haphazard resulted in many environmental hazards. One of the growing threats is noise pollution (Hardoy, et al, 1992), which is damaging human health like a silent killer. This paper is an attempt to study noise pollution in Karachi. In the previous studies on Karachi, noise measurements had generally been restricted to point based locations. There is a need to see more prominently, the impacts on the surrounding of the source. Therefore, authors sought to achieve the following objectives:
Today GIS excels at editing, data handling, interpolation, and visualization capabilities that are lacking in most models. The basic conception of GIS i.e. location, spatial distribution and relationships between the basic elements and spatial objects, facilitates the decision makers at various levels of governance. GIS is being used to monitor and forecast noise pollution patterns in many countries around the globe. http://www.railway-technology.com/contractors/computer/sound/"). It has been widely used in environmental modeling and analysis including noise pollution monitoring (http://www.co.honolulu.hi.us/ems/esd/reportb.htm) in the western hemisphere of the world. GIS could be an indispensable tool for noise analysis and management even in developing countries as Pakistan. In addition to its powerful capabilities in spatial database development, spatial data processing, managing and modeling, it provides visualization and map-making tools that can be used to effectively present the spatial variability of noise intensity. 2. PROBLEM AND THE STUDY AREA Pakistan stands within top ten among the countries of the world as far as population is concerned (PRB, 2001). Karachi is the only Metropolis in Pakistan and one of the worst effected cities of the world due to environmental pollution including noise. Few attempts were made in the 1990’s decade to collect noise (Ahmad, 1994) and air pollution data (Ghauri, 1998) at problem locations but spatial variations with in metropolis have been largely ignored. It was mainly due to less comprehension and under estimation of spatial techniques as well as the difficulty in collecting, processing and analyzing the data at micro-geographic scale. Nevertheless, with increasing availability of digital data and the special capabilities of Geographic Information System (GIS) to manage spatially referenced data, the spatial variations of noise pollution within a Metropolis can now be analyzed more easily and effectively. Therefore, the study area for this paper comprises of the known old city of Karachi i.e. from Guru Mandir to the Karachi Port as illustrated in figure 1. 3. PREVIOUS FINDINGS Although important non-industrial sources of noise pollution identified by contemporary studies in Karachi are Vehicular traffic, Loudspeakers, Construction work, Trains and Aircraft (SEPA, 1994) but the single most contributor in this regard remains the road traffic. Noise level in the urban center (core city or CBD) was unbearable. The internationally accepted tolerable range of 60 to 70 dB (A) had been far exceeded. The impact, of noise varies from zone to zone depending on the source of emission. The traffic congestion points in the central districts are highly noisy Table 1 illustrates the Noise Intensity levels at various locations in Karachi.
4. METHDOLOGICAL FRAMEWORK The techniques described below have been applied to acquire the appropriate results. Folgert, (1995) and Jian (1997) had applied varied GIS models and techniques for air pollution dispersion. Attempt has been made by the authors to illuminate noise risk zones in old city / core area of Karachi. Flow diagram demonstrating the GIS conceptual framework is illustrated as figure2. 4.1 Cartographic Techniques To develop any GIS model it is essential to make a suitable base map in vector format so that there can be attached attribute data to the geographical entities. Taking available Karachi metropolis guide map (on appropriate scale) and SPOT 10m-resolution image the enclosed figure 1 for Karachi has been produced. This map is consisting of the major infrastructure of the city urban area such as main roads, localities, railway-line, rivers, administrative divisional boundaries and Sample points. 4.2 Database Development and Integration One of the most important components of a GIS is the development of database. The initial stages of GIS development entailed a need assessment. Data sets from specific purpose are taken. The most significant available data includes geographical entities (map objects) and attribute data (intensity of noise). To understand the noise risk zones in a better way data pertaining to peak, average and low trends was analyzed. The database was later integrated with spatial objects on the map. 4.3 Spatial Modeling There are a number of spatial modeling methods available with respect to application, by virtue of efficacious GIS tools. Here the purpose of building spatial models is to demarcate the areal distribution of the noise pollution. 4.3.1 Surface Interpolation via IDW Surface Interpolation uses a defined or selected set of all the samples to estimate each of the output grid’s cell values. Inverse distance weighted (IDW) interpolation determines cell values using a linearly weighted combination of a set of sample points (Keith, 1997). The weight is a function of inverse distance. The surface being calculated should be a locationally dependent variable. IDW allows controlling the significance of known points, upon the interpolated values, based upon their distance from the output point. This method provided accurate weighted interpolated surface grid as well as isonoises. 4.4 Risk evaluation Criteria For the purpose of spotting Noise Risk Zones (NRZ) in old city of Karachi metropolis, the following evaluation criteria was adopted which resulted in Six Zones based on noise intensity levels.
5. RESULT AND DISCUSSION Figure 3, 4 and 5 clearly show the risk zones for peak, low and average readings respectively. A simple methodology to study noise pollution patterns and monitor its trends in Karachi metropolis with the help of cartographic techniques have been obtained. Figure 3 shows three distinct Noise Risk Zones (NRZ) for peak hours in Karachi. Wazir Mansion, Merewether Tower, Shaheen Complex, Lea Market, Agha Khan Jamatkhana, Plaza, Denso Hall, Garden and Burns Road are depicted as Very High Risk (VHR) locations. Guru Mandir, Goethe Institute, Eid Gah, Sindh Madrsa, Mauripur Truck Stand, Jinnah Bridge, Lucky Star, Numaish, Regal, Empress Market, Shara-e-Iraq, MetroPole, West Wharf and Zaibunisa Street are recognized as High Risk (HR) locations. Whereas Zainab Market lies in the Moderate Risk (MR) zone. Similarly Figure 4 also illustrates three distinct noise risk zones (NRZ), for Low Peak hours for the old city of Karachi. Guru Mandir, Plaza and Shaheen Complex are revealed as Low Risk (LR) locations. Agha Khan Jamatkhana, Garden, Denso Hall, Merewether Tower, Burns Road, Numaish, Jinnah Bridge, Goethe Institute, Empress Market, Eid Gah, Lea Market, Wazir Mansion, Regal, Lucky Star, Sindh Madrsa and Mauripur are uncovered as Tolerable Noise Zone (TNZ). While Truck Stand, Zainab Market, Shara-e-Iraq, Metro Pole, West Wharf and Zaibunisa Street are found to be in Safe Noise Zone (SNZ). Figure 5 portrays the average recorded values at 5-m from the sources. Wazir Mansion, Plaza, Guru Mandir, Denso Hall, Shaheen Complex, Merewether Tower, Goethe Institute, Agha Khan Jamatkhana, Garden, Burns Road and Eid Gah are found to be in Moderate Risk Zone (MRZ). Further Jinnah Bridge, Lea Market, Numaish, Empress Market, Regal, Sindh Madrsa, Lucky Star, Mauripur Truck Stand, Shara-e-Iraq, MetroPole and Zainab Market are found as Low Risk Zone (LRZ). Finally Zaibunisa Street and West Wharf are within the Tolerable Noise Zone (TNZ). It is evident from figures 3,4 & 5 that Wazir Mansion, Denso Hall, Shaheen Complex, Plaza, Guru Mandir and Merewether Tower are the problem locations at all times. This is because of the presence of a large number of Buses, Wagons1, Coaches2 and Rickshaws3 are plied here. These are the spots where two-way traffic is running 24 hours a day (especially at hours between 8:00 am to 8:00 pm), which ultimately generate high levels of noise. All of these locations are the convergence points and nodes or junctions of various roads. Conversely Zaibunisa Street, Zainab Market, Metropole and West Wharf are relatively safe islands as far as noise pollution is concerned. This could be because at these locations we do not have abundance of Buses, Wagons, Coaches and Rickshaws. The former three locations are one-way 1 A four wheel commercial vehicle used for plying goods 2 A minibus having a capacity of 22 seats 3 A three wheel, two stroke engine Para-transit mode streets and the West Wharf is almost at the seashore. The remaining locations fall in the middle, depending upon the time of the day. Looking at the city core as a whole, it can be concluded that
In this paper, GIS with powerful geocoding and spatial modeling capabilities, provided an ideal tool for spotting noise risk zones. It was established that conceptualization of spatial patterns of Noise Risk Zones (NRZ) within the metropolis of Karachi (Old City) was made possible for demarcation and extension of such Risk zones.. It was a model research that has provided a basis for a comprehensive study on noise pollution in Karachi using GIS techniques. The authors feel that point locations could have been spotted accurately by integrating a GPS (Global Positioning System) for the convenient comprehension of overseas audience. However, the use of GIS has improved not only the analytical capabilities for noise pollution management but also the ability to disseminate research findings to the decision makers and the public. The theme of the Seminar had precisely outlined, “Spatial information connotations are relevant in several dimensions of governance, and the use of Geographic Information System (GIS) can be expected to have an impact on governance”. It is intended that the methodology adopted here could be applied in similar urban settings elsewhere in the developing countries. 7. REFERENCES
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