Selecting a landfill site is a difficult task because the process depends on many factors and restrictions. Landfill is an optimal solution for the disposal of solid waste in Al-Musayiab Qadhaa, which is located in the northern part of Babylon Governorate. At the moment, there is no landfill site in that area that follows the scientific selection site criteria. For this reason, in this research, fifteen variables were considered (groundwater depth, rivers, soil types; agriculture lands use, land use, elevation, slope, gas pipelines, oil pipelines, power lines, roads, railways, urban centers, villages and archeological sites) using geographic information system (GIS) to find out the best suitable landfill site. In addition, two methods of multi-criteria decision-making were used to derive weights for criterion’s maps on GIS to obtain potential landfill sites. The first method is analytical hierarchy process (AHP) which was used to identify the weight for each criterion from the matrix of pairwise comparisons. The second method was the simple additive weighting (SAW) which is a simple method to solve the problem of the selection landfill sites. After comparison of the results obtained based on combining two final maps resulted from methods of AHP and SAW using GIS environment to determine the pixels percentage of matching and non-matching for two maps, two suitable candidate landfill sites were identified that satisfy the requirements with an area of 7.965–5.952 km². Area of these sites can accommodate the solid waste generated from the Qadhaa up to 2030.

Landfill siting is a complex process. It is one of the major problems in waste management, where many factors should be taken into consideration when selecting a suitable site for landfill in any given area. At the present time, there are many random waste disposal sites distributed throughout Al-Hashimiyah Qadhaa in Iraq. In this study, the Geographic Information System (GIS) and the Analytical Hierarchy Process (AHP) were used to select the best sites for landfill. The process of selecting sites for landfill in Al-Hashimiyah Qadhaa comprised two steps. First, fifteen different criteria were mapped and incorporated into overlay analyses within GIS software to produce the final suitability index map for the site. The second step comprises the exclusion of unsuitable areas from the final map to simplify identification of the candidate sites for landfill in the study area. The weightings of criteria were identified using AHP, and the weightings of the sub-criteria of each criterion were determined based on multiple factors. In order to accommodate solid waste from 2020 until 2030, two suitable candidate landfill sites were determined which fulfill the required area of 1.013 km² with areas of 1.374 km² and 1.288 km² respectively.

Landfill site’s selection represents a complicated process due to the large number of variables to be adopted. In this study, an arid area (Babylon Governorate as a case study) was selected. It is located in the middle region of Iraq. In this area, the landfills do not satisfy the required international criteria. Fifteen of the most significant criteria were selected for this purpose. For suitable weight for each criterion, the multi-criteria decision-making (MCDM) methods were applied. These methods are AHP and RSW. In the GIS software 10.5, the raster maps of the chosen criterion were arranged and analyzed. The method of change detection was implemented to determine the matching pixels and non-matching pixels. The final results showed that there are two candidate locations for landfills for each district in the governorate (ten sites). The areas of the selected sites were sufficient to contain the cumulative quantity of solid waste from 2020 until 2030.

The aim of this research was to simulate the water quality along the lower course of the Diyala River using Geographic Information Systems (GIS) techniques. For this purpose, the samples were taken at 24 sites along the study area. The parameters: total dissolved solids (T.D.S), total suspended solids (T.S.S), iron (Fe), copper (Cu), chromium (Cr), and manganese (Mn) were considered. Water samples were collected on a monthly basis for a duration of five years. The adopted analyzing approach was tested by calculating the mean absolute error (MAE) and the correlation coefficient (R) between observed water samples and predicted results. The result showed a percentage error less than 10% and significant correlation at R > 89% for all pollutant indicators. It was concluded that the accuracy of the applied model to simulate the river pollutants can decrease the number of monitoring station to 50%. Additionally, a distribution map for the concentrations’ results indicated that many of the major pollution indicators did not satisfy the river water quality standards.