Application weight mathematical model (WQI) to assess water quality for irrigation: A case study of Tigris river in Nineveh governorate

The current study included a qualitative assessment of the water of the Tigris river in Nineveh governorate for irrigation purposes using the sub-index model (IWQI) that was applied to eleven parameters of irrigation water to identify the quality of the river's water for irrigation. Water samples were collected monthly from nine sites on the river starting from November. Until august to conduct physiochemical analyzes, as well as calculating the irrigation parameters. The results indicated that the water quality index values ranged between (29.08-41.46). Despite the high values of the index with the course of the river, especially the city of Mosul, due to the drainage of sewage through many estuaries spread on both sides of the river, the water quality in the studied sites was of the excellent water category for irrigation.