Water pollution utilizing the relative weight water quality index with geographic information system for Tigris river at Wassit.

For all living things of all kinds, water is one of the most important natural resources. Tigris is one of two main rivers in Iraq that has been affected by wastewater pollution. Four water sampling point were taken along The length of Tigris river at Wassit governorate within the study area with a length of about 250 km within the study area from (33°02'12"N, 44°44'01"E) to (32°31'23"N, 45°54'53"E) navigated by GPS (GARMIN 72), coordinates system WGS_1984_UTM_Zone_38N. Water quality analysis includes a number of parameters; Relative Weight WQI was used to assess water Quality River according to mathematical equation. Four water quality parameters were considered, those are Hydrogen Ion concentration (pH), Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD5), Nitrate (NO3), Phosphate (PO4) and Sulfate (SO4) for the period (2020 to 2022). Relative Weight Water Quality Index (RW-WQI) analysis technique according to arithmetic weighted formula then using "Geographical Information System (GIS)" technique – Interpolation(SPL) method was used to display the results and analyzes as accurate and up-to-date color maps to describe water quality. Indicate the results from the arithmetic weight (WQIs) analysis classified from poor to very poor for the period 2020 to 2022. All types of wastewater must be properly and completely treated before it is discharged into the water stream. [ABSTRACT FROM AUTHOR]