Wednesday, April 2, 2008 : 8:40 a.m.

Fuzzy Pattern Recognition Model for Ground Water Vulnerability Assessment using GIS-based DRASTIC System

Dhundi Raj Pathak, Akira Hiratsuka, Ph.D., Isao Awata, Ph.D. and Luonan Chen, Ph.D., Osaka Sangyo University

The ground water scenario, which is one of the major natural resources in developing countries like Nepal for drinking purpose, is not very encouraging primarily due to the imbalance between recharge and exploitation. The drawdown of ground water levels due to the over exploitation and thus extracted water from shallow aquifer has been contaminated by the infiltration of pollutants from polluted river and land surface is continuous and serious problems in haphazard urbanized cities in developing countries. Management of ground water source and protecting its quality is therefore essential to increase efficient use of existing water supplies. Recognition of ground water vulnerability to pollution will help in protection ground water sources and managing ground water quality conflicts. In fact, ground water monitoring and mathematical modeling are very costly in regional scale vulnerability assessment, hence subjective modeling is needed to assess the potential of ground water contamination by nonpoint sources over large geographical areas involving a variety of hydrogeological settings. In this paper, a fuzzy pattern recognition model for assessing the ground water vulnerability to pollution is presented in which the standard value matrix of factors is constructed on the basis of the data in the DRASTIC system and then converted into membership degree levels of samples, which are expressed by linguistic variables. Finally, it is compared with the GIS based DRASTIC model in a case study of Kathmandu Valley, Nepal. It is shown that by taking the fuzzyness into consideration, the fuzzy pattern recognition model reflects more efficiently the fuzzy nature of the ground water vulnerability to pollution and is more applicable for ground water management and monitoring in regional scale.

Keywords: Ground water vulnerability, fuzzy pattern recognition, DRASTIC, Linguistic variables, GIS, Developing countries

Dhundi Raj Pathak, Osaka Sangyo University He received his M.Sc. (Eng.) in Geotechnical Engineering in 2005 from Department of Civil Engineering, Institute of Engineering, Pulchowk Campus, Tribhuwan University, Nepal. He is currently a graduate student (Ph.D. Degree) in Graduate School of Engineering at Osaka Sangyo University, Japan. His research interests are GIS based modeling, ground water management and vulnerability assessment, study of hydrogelogical parameters and contatminant sources pertinent to ground water pollution, and contaminant transport phenomena into ground water systems.


2008 Ground Water Summit