IIIT Hyderabad Publications
A Geospatial analysis towards achieving water security - case study of Hyderabad
Author: Rahul Kumar Rai
Report no: IIIT/TH/2017/5
Advisor:K S Rajan
Water security, simplistically defined as the capability of a society to ensure that its demands for water are met, is an important aspect which governs not only the well being of individuals in the present, but also acts as a deciding factor for the future prospects and expansion plans of any urban sprawl. The city of Hyderabad is rapidly expanding, resulting in a drastic increase in the population of the metropolis. It is estimated that with this rate of urban growth, the current municipal water distribution system would not be able to fulfil the demands efficiently of the city. Water problem has became the key obstacle for the sustainable development of any city and same goes with Hyderabad. Though the city has a large amount of water bodies within its perimeter , most of them are not being utilized for water distribution. Instead, water is being pumped in the city from rivers far-off. However, the initial and operational cost of such long-distance water projects in terms of resources and energy consumption is several times higher than that of local distribution system. Thus, though this model is fulfilling the current demands of the city, it is not sustainable and cannot be scaled up while maintaining profitability. The solution to this problem needs to rely upon local water bodies in the city. Because of its undulating geography and rocky soil, Hyderabad has a large number of lakes within its vicinity. Several of these are natural, and an equally significant number of reservoirs are man-made. These reservoirs were built with the primary intent of harnessing surface run-off water for local use. However, with rapid urbanization, they succumbed to pollution and encroachment, because of which they are not being utilized currently for supplying water to the city. If these water bodies are included in the citys main water supply, it may prove to be an efficient solution for the cities water issues. The approach described above is more of a proposal, verification of which needs comparative analysis of the citys overall water consumption and the volume of water that can be drawn from the lakes. This poses a major obstacle in verification of the approach described. Calculation of water volume for any irregular shaped water body is a complicated and laborious task. As the circle of study expands from a small locality to a city, state or a country, existing methods to calculate the water volume tend to become highly expensive and thus non scalable. Therefore, a need arises to devise a simpler, yet highly efficient method which can be generically applied to any geographical area for analysing water volume of lakes. The objective of this thesis is to devise a system that relies on local water bodies for supplying water to the city, and in the process propose efficient ways to calculate water volume of any irregularly-shaped water body. In this study, a novel system has been proposed which would utilize local water bodiesfor water distribution in the city. It also presents an efficient approach using open source geospatial technologies (GDAL/OGR library) to determine the volume of water in irregularly shaped lakes with embankment. The approach uses spatial vector data for boundaries, vector data for embankments, and depth data to calculate the amount of water present in any given lake. Algorithms for water volume calculation were written as python modules, leveraging the capabilities offered by the programming language and open source GIS library - the OGR/GDAL library. Calculations for water volume of lakes gave results with considerable accuracy. The error percentage in water volume was found to be mainly dependent on the size of the lake under consideration. It was noticed that for medium-sized lakes with capacity between 50 Mcft. and 70 Mcft, the error percentage was 6.5% and for larger lakes with capacity between 2800 Mcft. to 3500 Mcft, the error percentage was 7.51%. The error percentage was also found to be dependent on the granularity of the grid which was used to model the surface of lake. When applied to all the lakes in Hyderabad, the algorithms gave a gross 9 TMC of water which could be used for supplying to the city. Population data for the city was also gathered from official sources and using the per-capita water consumption of the city, total water demands of the city were estimated. When the water consumption was compared against the volume available for supply, it was found that 67% of the population can be supplied water from local water bodies. This number, though fairly decent, can be improved if the lakes are deepened. By manipulating the embankment depths of lakes used for calculation, this scenario was simulated and it was observed that with increased embankment depths, the water storage capacity of lakes increased to an extent that they could easily meet the demands of 80% of the citys population. This study targets only quantitative analysis of water for distribution to the city. Qualitative analysis of water has been out of the scope of the problem definition and the related research work. This observation leads to the conclusion of this thesis on a note that local water bodies can be reliable sources of water, providing an efficient means to solve the water issues being faced by the city, and ensuring that water security is not compromised.
Full thesis: pdf
Centre for Spatial Informatics
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