Yes, GIS are useful tools for assessing the water quality analysis provided that you have the required datasets/information for these analyses. The following article may be useful for you:
Conference Paper Water quality management using GIS and RS tools
You should be carful on how to use gis in water quality assessement , firstly you must choos the best model to use it , then you have to choise which type of study you want to make, if yoy want to make sub-area delimitahion for irrigation or drinking you have to interpolate the indices adequate to that , if you want to make an investigation about water/rocks interactions you have to work with the chemical parameters of water .
Having data related to this quality, you can perform spatial analysis in a GIS environment and visualize areas of poor and good water quality. Some tools of GIS software may perform several interpolation methods to modeling the quality in all study area.
Water quality involved physical, chemical and bacteriological pollution. Determination of Each parameters require very specific method and different type of instruments.
Virendra Kumar Saxena Suresh Nathan Nadaraja Elisabete Monteiro Antero Vasquez Mehran Akrami Thanks a lot for your comment and contribution, really thanks.
GIS is just a tool, your purpose depended on the type of data and the accuracy of it. SO, if you have little points, you can use GIS to make several maps for one factor by different interpolations methods to find the best to your study area. As well, you can use another software beside GIS like R, SPSS, and rockwork.
There is nothing like spatial display of water quality of a river, lake and rivers using GIS. It can be derived by measurements or modeling. GIS is an ideal tool for presenting the current and future status of water quality, in the horizontal or vertical scale (like depth wise). Various options in GIS help display the results which could be understandable for most of the people. The recent use of the computing method, "python", has made GIS as a versatile tool for the water quality analysis. In stead of using GIS as a front end and back end of an analysis to display the results, with the recent advancement of computing system, now analyses can be performed within GIS. Recent advancements (computer and computing systems) have made GIS a valuable tool for water quality analyses all over the world.
Yes, it provides the spatial dimension of the phenomenon studied, and through it, the mechanisms of pollutant spread and the impact of water quality can be understood