Home > Geospatial Application Papers > Environment > Water Pollution


Mapping of Water Quality Index (WQI) using Geographical Information System (GIS) as Decision Supporting System Tool

K. Veerabhadram
Assistant Professor, Department of Environmental Studies, College of Engineering
GITAM, Visakhapatnam-530 045, India

Contamination of drinking water has become a major challenge to the Environmentalist in the rapid developing countries. As more and more people are exposed to contamination of drinking water, many issues arise that not only involve premeditating the contaminated water, but also preventing similar situations from occurring future. Te drinking water is contaminate through the pipe distribution system or directly through ground water. By mapping using the Decision Support system like GIS can be useful for taking quick decision as graphical representation would be easy to take decision by the policy makers.

A water quality index provides a single number (like a grade) that expresses overall water quality at a certain location and time based on several water quality parameters. The objective of an index is to turn complex water quality data into information that is understandable and useable by the public. A single number cannot tell the whole story of water quality; there are many other water quality parameters that are not included in the index. The WQI presented is not specifically aimed at human health or aquatic life regulations.

Assistant Professor, Department of Environmental Studies, College of Engineering, GITAM, Visakhapatnam-530 045, India

Decision makers in environmental fields face the difficult challenges of anticipating the potential biophysical and socioeconomic impacts of managements and policy interventions over regions that may vary dramatically in terms of climates, soils, topography, land use and other factors. Leung(1997) addressed a host of conceptual, theoretical, systems.

However, a water index based on some very important parameters can provide a simple indicator of water quality. It gives the public a general idea the possible problems with the water in the region.

Objective of Water Quality Index
The main objective of Water Quality Index is to turn complex water quality data into information that is understandable and useable by the public. Water Quality Index based on some very important parameters can provide a simple indicator of water quality. it gives the public a general idea of the possible problems with water in a particular region. The indices are among the most effective ways to communicate the information on water quality trends to the public or to the policy makers and water quality management. It is also defined as a rating reflecting the composite influence of different water quality parameters on the overall quality of water .the concept of indices to represent gradation in water quality

WQI Calculation
For calculation of WQI, section of parameters has great importance. Since selection of too many parameters might widen the quality index and importance of various parameters depends on the intended use of water, twelve physico-chemical parameters namely pH, Conductivity, Turbidity, Total hardness, Mg hardness, Ca hardness, TDS, Chlorides, Alkalinity, Sulphate, Nitrates, Iron, were used to calculate WQI.

Importance of GIS as Decision Support System
A spatial Decision Support System ( SDSS) is a computer –based system designed to assist decision system. Typically, such a system will include spatial data relevant to the decision, analytic tools to process the data in ways meaningful for decision makers, and output or display functions. Thus, an SDSS has considerable overlap with the functionality of a Geographical Information System (GIS). According to the National Center of Geographic Information and Analysis (NCGIA) an SDSS is an “ interactive, computer-based system designed to support a user or group of users is achieving a higher effectiveness of decision making while solving a semi-structured spatial decision problem”.

Since there are many examples of SDSS, for specific decisions in the environmental domain, particularly in the areas of water pollution, crop, livestocks, flood, and forest management. National reliance of Ground Water has increased exponentially over the past three decades. Although contamination of Ground Water has been occurring for many centuries, the current concern for control of water pollution and for maintenance of high quality waster supplies has stimulated an interest in the protection of Ground Water resources from contamination. The level of Ground Water contamination depends on the physical characteristics of the area, the chemical nature of the pollutant and the method of application. This paper gives a case study of an area appraises of a domain of the study area, which incorporates the influence of the physical characteristics of any area of evaluate an index that reflects the vulnerability of an area towards of Ground Water pollution.

Objectives of the proposed project
The main objectives of the project work are as follows.
  1. Analysis of the water samples for various parameters as per WHO standards and determination of Water Quality Index (WQI) that reflects the extent of the ground water pollution. By using Geographical Information System Software (GIS) the thematic maps can be drawn based on the data available for the entire study area, thus making Geographic Information system (GIS) as decision support system.
  2. To identify the extent of errors arises in the calculation of Water Quality Index (WQI) using Artificial Intelligence (AI) know the ground water contamination which depends on many physical characteristics such as Topography, depth of water, soil of media and hydraulic conductivity applying
  3. To prepare one final composite map based on all thematic maps prepared on individual parameters.
To develop an expert system for decision makers and prepared a software by which large number of data can be handled in a user friendly manner