A new quadrant constellation graph-based water quality index and map

Abstract

Water quality (WQ) evaluation is very important issue in human health and environment management. Many WQ evaluation (WQE) methods based on statistical methods and multi-criteria decision making (MCDM) methods have been developed and used. The common drawback is that they lack in visualization/intuitiveness of the WQE results. They evaluate the WQ level only quantitatively. To intuitively represent the WQ level, the previous WQE methods have applied some additional graphical methods such as concentration/distribution/contour maps combined with complicated interpolation techniques based on geographic information system. The objective of this research is to develop a new effective approach to evaluate the WQ level not only quantitatively but also intuitively without requiring additional complicated graphical technique. To do this, we proposed a new quadrant constellation graph-based water quality index (QCG-WQI) and map (QCG-WQM). The QCG-WQI evaluates the WQ level quantitatively, and QCG-WQM evaluates the WQ level intuitively. To demonstrate the effectiveness, three illustration cases were considered and compared with the results from some well-known MCDM methods. The results demonstrate that the new approach is very effective intuitive and quantitative WQE tool. It could be widely applied to not only WQE and environmental evaluation but also MCDM problems in many physical research works.