Evaluation of Seasonal a Spatial Variation of Groundwater Quality by Determining Factors Associated With Water Quality Using Multivariate Analytical Methods, Erbil Central Sub-Basin

Abstract

The study area is located in the northern Iraqi province of Erbil, covering a total area of about 1400 Km2 (3.5% of Iraq). The Erbil basin is mostly covered by Quaternary sediments, with only a few outcrops of Miocene – Pliocene formations in the east and northeast of Sharabot-Dedawan highlands, Avanah Mountain in the west and southwest in narrow strips, and Damirdagh in the north. The lithology of sediments ranges from clay, silt, sand, and gravel (sandstone, clay stone, and conglomerate). Erbil Basin, also known as Dashty Hawler Basin, Erbil provinces is the largest groundwater reservoir, with a surface area of 3200 Km2 and a depth of approximately 800 meters. Erbil Basin, one of the Middle East's most important groundwater basins, is bounded on the north by the Greater Zab River and on the south by the Lesser Zab River. Thirty water samples (27 samples of groundwater wells, and 3 samples of wastewater channels) were collected during May (Water surplus period) and September (Water deficit period) 2020 in Erbil central sub-basin and analyzed. Physical analyses include temperature (T), pH, Electrical Conductivity (EC), Total Dissolved Solids (TDS), Biological Oxygen Demand (BOD5), Chemical oxygen demand (COD), Dissolved oxygen (DO), Total Suspension sediments (TSS), whereas the geochemical analysis included concentration determination of the major, minor and trace elements. This article aims to evaluate the pollution in groundwater of the Erbil central sub-basin due to different kinds of wastewater, the samples of water in the study area were collected from different locations and sources, deep wells, and waste. all chemical, physical, and trace elements parameters are presented in this work, the pollution has been founded in the study area due to waste water by Kahrez (old groundwater distribution in Erbil basin), cesspools, and septic tanks. © 2023, Iraq Geological Survey. All rights reserved.