Applying grey systems to analyze water quality on the river Chira watershed

Due to people's opposition to any mining company exploiting some ore deposit close to their community, these projects, in some cases, are never carried out properly, resulting in informal miners illegally exploiting these areas and polluting important river watersheds. Hence, a water quality assessment is necessary. In this work, to assess the water quality of the Chira river watershed was used the Grey Clustering method, which is based on grey systems, in which informal miners affected the activity in the Tambogrande area in Piura, Peru. In this case study, 17 monitoring points were determined (1-17), all of them were analyzed using 6 criteria of evaluation (C1-C6). The results of this study showed that there was some level of pollution due to the activity of informal miners, but this does not involve a great negative impact. These results could help to demonstrate that the expulsion of formal mining companies from ore deposits can cause pollution to a higher level than expected. Some monitoring points on the Ecuador -Peru boarder showed high pollution, which could mean illegal mining activity in that area and would be subject for future study.