Irrigation Water Susceptibility Indexing Method, Using Pesticide DRASTIC and Water Quality Index, for Basara Basin; Kurdistan Region-Iraq

Abstract

The increasing use of chemical fertilizers, with spreading industrial and urbanization activities in the whole area of the Basara basin expected to affect the quantity and quality of water from these sources of pollutants. The main aim of this research revolves around the integration of the intrinsic vulnerability Index (VI) through applying the pesticide DRASTIC method, with the irrigation quality index, to assess the irrigation susceptibility Index (SI) for the basin. The quality of groundwater for its suitability for irrigation purposes was measured by its hydro-chemical parameters in this research. Thirty-one water samples were collected in the studied area during the post-monsoon period of the year 2018. Samples have been tested for both physical and chemical parameters. The Geographic Information System (GIS) has been used for this assessment. The results indicate that water movement directions of streams, the geological formation of aquifers, land slope, and contamination sources have a great impact on water quality, vulnerability, and susceptibility index. The pesticide DRASTIC map categorizes the basin into five classes as (very low, low, moderate, high, and very high). Results show that the most vulnerable area to pollution is those that used for intensive agricultural and industrial sectors, besides the areas with high permeability and lands with minimum surface slopes which are intensively used as cultivated areas. The results indicate that the incorporation of both hydrogeological and hydro-chemical datasets enables more realistic evaluations than those of an individual dataset to estimate the groundwater contamination susceptibility of an aquifer. This work offers the decision-makers a clear photo of the quality of irrigation water and the area most vulnerable to contamination. This will be used as the basis for future research to mitigate the effects of vulnerable areas and to establish a new groundwater management strategy in the basin.