| 1. |
- Abdullah, Twana, et al.
(författare)
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Assessing the Vulnerability of Groundwater to Pollution Using DRASTIC and VLDA Modelsin Halabja Saidsadiq Basin, NE, Iraq
- 2016
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Ingår i: Journal of Civil Engineering and Architecture. - USA : David Publishing Company. - 1934-7359 .- 1934-7367. ; 10:10, s. 1144-1159
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Tidskriftsartikel (refereegranskat)abstract
- Groundwater plays important roles as one of the essential source of water supplies of the studied area. Consequently, it needs to be prevented from contamination. In this study, two methods have been examined, namely DRASTIC (depth to groundwater, net recharge, aquifer media, soil map, topography, impact of vadose zone and hydraulic conductivity) and VLDA (vadose zone lithology, land use patterns, depth to groundwater and aquifer media) to model a map of groundwater vulnerability for contamination of the basin. The standard DRASTIC vulnerability maps classified the basin of four vulnerability index zones: very low (34%), low (13%), moderate (48%) and high (5%). While the VLDA model classified the area into four categories as well: low (2%), moderate (44%), high(53%) and very high (1%). The results demonstrate that there is a significant dissimilarity in the rate of vulnerability. Validation of the constructed maps is required to confirm the validity of the theoretical sympathetic of current hydrogeological conditions. In this study, nitrate concentration analysis was selected as a contamination indicator to validate the result. The nitrate concentration of two different seasons (dry and wet) was analyzed from (30) watering wells, considerable variations in nitrate concentration from dry to wet seasons had been noted. Consequently, it points toward that groundwater in the HSB (Halabja Saidsadiq Basin) is capable to receive the contaminant due to suitability of overlies strata in terms of geological and hydrogeological conditions. Based on this confirmation, the result exemplifies that the degree and distribution of vulnerability level acquired using VLDA model is more sensible than that attained from the standard DRASTIC method .In addition, the DRASTIC models need to be modified based on the land use pattern, which clarifies the role of human activity on the vulnerability system.
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| 2. |
- Abdullah, Twana, et al.
(författare)
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Assessment of groundwater vulnerability to pollution using two different vulnerability models in Halabja-Saidsadiq Basin, Iraq
- 2020
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Ingår i: Groundwater for Sustainable Development. - : Elsevier. - 2352-801X. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Groundwater aquifer in Halabja-Saidsadiq Basin considered as one of the most important aquifers in terms of water supplying in Kurdistan Region, NE of Iraq. The growing of economics, irrigation and agricultural activities inside the basin makes it of the main essentials to the region. Therefore, pollution of groundwater is of specific worry as groundwater resources are the principal source of water for drinking, agriculture, irrigation and industrial activities. Thus, the best and practical arrangement is to keep the pollution of groundwater through. The current study aims to evaluate of the vulnerability of groundwater aquifers of the study area. Two models were applied, to be specific VLDA and COP to develop maps of groundwater vulnerability for contamination. The VLDA model classified the area into four classes of vulnerability: low, moderate, high and very high with coverage area of (2%,44%,53% and 1%), respectively. While four vulnerability classes were accomplished dependent on COP model including very low, low, moderate and high vulnerability classes with coverage areas of (1%, 37%, 2% and 60%) respectively. To confirm the suitability of each map for assessment of groundwater vulnerability in the area, it required to be validated of the theoretical sympathetic of current hydrogeological conditions. In this study, groundwater age evaluated utilizing tritium isotopes investigation and applied it to validate the vulnerability results. Based on this validation, the outcome exhibits that the vulnerability classes acquired utilizing VLDA model are more predictable contrasted with the COP model.
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| 3. |
- Abdullah, Twana, et al.
(författare)
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Classification of groundwater based on irrigation water quality index and GIS in Halabja Saidsadiq basin, NE Iraq
- 2016
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Ingår i: Journal of Environmental Hydrology. - 1058-3912 .- 1996-7918. ; 24
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Tidskriftsartikel (refereegranskat)abstract
- Assessment of groundwater for irrigation purpose is proposed using the Irrigation Water Quality Index (IWQI) within the GIS environment. The model was applied to several aquifers in the study basin. Water samples were collected from thirty-nine sites from both water wells and springs from the dry season (September 2014) and the wet season (May 2015). Samples were tested chemically and physically for several variables: EC, Ca+2, Mg+2, Cl-, Na+ and HCO3- and SAR. The accuracy and precision methods were applied to find out the uncertainty of the chemical analysis results and its validity of application for the geochemical interpretations. Based on the spatial distribution of IWQI, the groundwater quality of HSB classified into several classes of both dry and wet seasons in terms of its restrictions on irrigation purposes. The classes include, Severe Restriction (SR), High Restriction (HR) and Moderate Restriction (MR). The coverage areas of all three classes are 1.4%, 52.4% and 46.2% for the dry season and 0.7%, 83.3% and16% for wet seasons respectively. The considerable variations in all these classes have been noted from dry to wet seasons, this might be related to increasing the aquifer recharges from precipitation and decreasing the aquifer discharges by the consumers in the wet season. Then the model was validated based on the relation between the aquifer recharge and spatial distribution of IWQI, the result of this validation confirmed the outcome of this study.
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| 4. |
- Abdullah, Twana, et al.
(författare)
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Groundwater assessment of Halabja Saidsadiq Basin, Kurdistan region, NE of Iraq using vulnerability mapping
- 2016
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Ingår i: Arabian Journal of Geosciences. - : Springer Science and Business Media LLC. - 1866-7511 .- 1866-7538. ; 9:3
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Tidskriftsartikel (refereegranskat)abstract
- Halabja Saidsadiq Basin is located in the northeastern part of Iraq covering an area of about 1278 km2 with a population of about 190,727. Groundwater is the principal source of water in this area. Agricultural practices within the basin are widespread and located close to groundwater wells. This poses imminent threat to these resources. DRASTIC model integrated with GIS tool has been used to evaluate the groundwater vulnerability of this area. In addition, theDRASTIC model was modified using nitrate concentrations and sensitivity analysis to modify the recommended weighting value to get accurate results. The modified rates were calculated using the relations between each parameterand the nitrate concentration in the groundwater based on the Wilcoxon rank-sum non-parametric statistical test. While, to calibrate all types of modifications, the Pearson’s correlation coefficient was applied. The standard vulnerability map of the studied basin classified the basin into four zones ofvulnerability index including very low (34 %), low(13 %), moderate (48 %), and high (5 %) vulnerability index, while the combined modification classified the area into five classes: very low (7 %), low (35 %), moderate (19 %), high (35 %),and very high (4 %). The results demonstrate that both modified DRASTIC rate and weight were dramatically superior to the standard model; therefore, the most appropriate method to apply is the combination of modified rate-weight.
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| 5. |
- Abdullah, Twana, 1977-
(författare)
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Groundwater Vulnerability Assessment to pollution in Different Soil and Rock Materials
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The augmentation of human population regularly corresponds with change in the land cover, including expansion of urban areas, which imposes increasing the available amount of domestic and drinking water. The study area, Halabja-Saidsadiq Basin, is situated in the Northeast of Iraq and is one of the major groundwater sources of the region. As the surface water sources are not enough in the studied area, it has become necessary to use groundwater at an increasing rate. Usually, a huge amount of groundwater is plentiful in the alluvial deposits or rock outcrops where the urban areas are frequently situated. Such areas face a huge risk of pollution of groundwater due to producing different sources of a contaminant from human's activity. Keeping these aspects in view, groundwater vulnerability studies have been carried out in the current studied basin. The main objective of this work is to investigate the environmental impacts on groundwater quality and recognize the groundwater vulnerability in the area so that the groundwater can be protected from probable contaminations.In the current study, DRASTIC model has been applied since it is one of the most proper useful methods available for the assessment of the groundwater vulnerability. This model has been modified in different ways to achieve the obvious vulnerability condition in the area; likewise, different further methods have been applied for comparison purposes such as: weight modified VLDA and standard COP models. In addition, the applied models were validated by comparing its findings against the estimated groundwater ages and the observed water characteristic qualities within the region in two successive seasons.According to the spatial distribution of irrigation water quality index, groundwater at the studied basin classified into three group for both dry and wet seasons, namely, Sever Restriction (SR), High Restriction (HR) and Moderate Restriction (MR). The coverage area of all three classes are (1.4%, 52.4% and46.2%) for dry season and (0.7%, 83.3% and16%) for wet seasons, respectively. While, refer to the water quality index for drinking purpose, groundwater in this basin reveals a permissible to excellent groundwater quality of the dry season and a good to excellent groundwater quality of the wet season. The high level of a good groundwater quality in the wet season compared to the dry season might be expected to the groundwater recharge during the winter and spring periods, which lead to dilution of chemical component, in contrast high irrigation and agricultural activities and groundwater discharge in the dry season leads to increase the concentration of chemical component.Field and official data were collected to review several environmental impacts and were used to map standard DRASTIC vulnerability model for the study basin. Based on this model, the study area was classified into four zones of vulnerability indexes, comprises a very low, low, moderate and high vulnerability index with a coverage area of (34%, 13%, 48% and 5%) respectively.In the first modification step, the rate and weight value of each parameter in DRASTIC model is modified. Nitrate concentration from 39 groundwater samples was used for modifying the recommended standard rating value based on the Wilcoxon rank-sum nonparametric statistical test and then sensitivity analysis was used to modifying recommended standard weighting value of each parameter. To calibrate the modified rate, the Pearson's correlation coefficient was applied to estimate the relation between DRASTIC values and nitrate concentrations in groundwater samples. For the first modified model, the correlation coefficient was 72% that was significantly higher than 43% achieved for the standard model. The modified model classified the area into five vulnerability classes, including (very low, low, moderate, high and very high) with covered area of (7%, 35%, 19%, 35% and 4%), respectively.The second modification of DRASTIC model was based on land use and land cover for the studied area. The land use and land cover (LULC) map prepared using ERDAS IMAGINE software from two different scenes of Landsat Thematic Mapper (TM). The LULC map indicates that only five classes of LULC can be identified: these are: barren land, agricultural land, vegetation land, urban area and wet land or water body. The modified DRASTIC based on LULC map classified the area into five classes with different coverage area of each class: very low (1.17%), low (36.82%), moderate (17.57%), high (43.42%) and very high (1.02%).The third modified method of the current study is the modification of DRASTIC model based on Lineament feature of the study basin. A lineament map is extracted from Enhanced Thematic Mapper plus (ETM+) satellite imagery using different techniques in remote sensing and GIS. The lineament density map demonstrates that only six classes of lineament density can be identified ranged from (0-2.4). The third modified DRASTIC model classified the area into four vulnerability categories: very low (28.75%), low (14.31%), moderate (46.91%) and high (10.03%).The fourth effort to modify standard DRASTIC model is the application of Analytical Hierarchical Process (AHP) to assess the weight value of each parameter. The modified DRASTIC vulnerability index values based on AHP method ranged between (65.82–224.1) with five vulnerability classes comprises (very low to very high).Weight modified VLDA and standard COP models were also applied to map vulnerability system in the study basin. The vulnerability outcome based on weight modified VLDA model revealed that a total of four ranges of vulnerability indexes had been distinguished ranging from low to very high with vulnerability indexes (2.133-9.16). Subsequently, based on the standard COP model, the area is also divided into four vulnerability classes ranging from very low to high with index value ranged from (0.79) to (6.2).All applied models in the study basin were compared to each other and validated to clarify the validity of the theoretical sympathetic of current hydrogeological conditions and to show the accuracy of the modeled vulnerability system. Two methods were applied for the validation of the result, in the first approach; nitrate concentration analysis has been selected; the nitrate differences between two following seasons (dry and wet) were analyzed from (39) water wells. In the second approach, groundwater vulnerability was assessed based on estimated groundwater age from range of tritium (3H) value in the groundwater samples from different groundwater aquifers in the studied area. The results of both validation methods verify the sensibility of the gradation and distribution of vulnerability levels acquired using the modified DRASTIC model based on (rate and weight modification, weight modification based on AHP process and effect of LULC on DRASTIC model) and also applying weight modified of VLDA model.
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| 6. |
- Abdullah, Twana, et al.
(författare)
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Groundwater Vulnerability Mapping Using Lineament Density on Standard DRASTIC Model : Case Study in Halabja Saidsadiq Basin, Kurdistan Region, Iraq
- 2015
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Ingår i: Engineering. - : Scientific Research Publishing, Inc.. - 1947-3931 .- 1947-394X. ; 7:10, s. 644-667
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Tidskriftsartikel (refereegranskat)abstract
- Groundwater is the most important source of water in the Halabja-Saidsadiq Basin. In this study, to generate a map of groundwater pollution vulnerability of the basin, the standard DRASTIC method has been applied. Due to the close relation between lineament density and groundwater flow and yield, the lineament density map was applied to the standard DRASTIC model in order to ensure accuracy towards the consideration of the effects of potential vulnerability to contamination. A lineament map is extracted from Enhanced Thematic Mapper plus (ETM+) satellite imagery using different techniques in remote sensing and GIS. The lineament density map illustrates that only six classes of lineament density can be identified ranged from (0 - 2.4). The lineament density map was rated and weighted and then converted to lineament index map. This index map is an additional parameter which was added to the standard DRASTIC model so as to map the modified DRASTIC vulnerability in HSB. The standard vulnerability map, classified the basin into four vulnerability index zones: very low (34%), low (13%), moderate (48%) and high (5%). While the modified model classified the area into four categories as well: very low (28.75%), low (14.31%), moderate (46.91%) and high (10.04%). The results demonstrate that there is no significant variation in the rate of vulnerability. Therefore, the nitrate concentration between two different seasons (dry and wet) was analyzed from (30) water wells, considerable variations in nitrate concentration from dry to wet seasons had been noted. Consequently, it confirmed that the HSB are capable to receive the contaminant because of suitability in terms of geological and hydrogeological conditions. Based on this verification, it could be claimed that the effect of lineament density is weak on the vulnerability system in HSB, because of its low density value.
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| 7. |
- Abdullah, Twana, et al.
(författare)
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Groundwater Vulnerability Using DRASTIC and COP Models : Case Study of Halabja Saidsadiq Basin, Iraq
- 2016
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Ingår i: Engineering. - USA : Scientific Research Publishing. - 1947-3931 .- 1947-394X. ; 8:11, s. 741-760
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Tidskriftsartikel (refereegranskat)abstract
- To avoid groundwater from contamination, the groundwater vulnerability tool can be examined. In this study, two methods were applied, namely: DRASTIC (Groundwater depth, Net recharge, Aquifer media, Soil map, Topography, Impact of vadose zone and Hydraulic Conductivity) and COP (Concentration of flow, Overlying layer and Precipitation) to model groundwater vulnerability to pollution. The result illustrated that four vulnerability classes were recognized based on both models including very low, low, moderate and high vulnerability classes. The coverage areas of each class are (34%, 13%, 48% and 5%) by DRASTIC model and (1%, 37%, 2% and 60%) by COP model, respectively. The notable dissimilarity between these two models was recognized. For this reason, nitrate elements were selected as a pollution indicator to validate the result. The concentrations of nitrate were recorded in two following seasons in (30) watering wells; as a result, the substantial variation was noted. This indicates that contaminants can be easily reached the groundwater due to its suitability in geological and hydrogeological conditions in terms of contaminant transportation. Based on this confirmation, the standard DRASTIC method becomes more sensible than COP method.
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| 8. |
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| 9. |
- Abdullah, Twana, et al.
(författare)
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Hydrogeochemical Evaluation of Groundwater and Its Suitability for Domestic Uses in Halabja Saidsadiq Basin, Iraq
- 2019
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Ingår i: Water. - Switzerland : MDPI. - 2073-4441. ; 11:4
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Tidskriftsartikel (refereegranskat)abstract
- Evaluation of the hydrogeochemical characteristics and groundwater suitability for domestic use was conducted in the Halabja Saidsadiq Basin in the northeastern part of Iraq. The total studied area is about 1278 km 2 with a specific Mediterranean-type continental interior climate, which is cold in winter and hot in summer. To conduct the required laboratory chemical analysis for groundwater samples in the studied basin, 78 groundwater samples, in total, were collected from 39 water wells in the dry and wet seasons in 2014 and analyzed for major cations and anions, and the results were compared with the permitted limits for drinking water. An examination of the chemical concentrations of the World Health Organization drinking water norms demonstrate that a large portion of the groundwater samples is suitable for drinking, and a preponderance of groundwater samples situated in the class of hard and very hard water types for both seasons. Suitability of groundwater for drinking use was additionally assessed according to the water quality index classification. This showed that more than 98% of groundwater samples have good water quality in the dry and wet seasons. Conversely, the classification of groundwater samples based on Piper’s diagram designates that the groundwater type is alkaline water, with existing bicarbonate along with sulfate and chloride. However, water–ock exchange processes and groundwater flow have been responsible for the dominant water type of Ca–g–CO3.
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| 10. |
- Abdullah, Twana O., et al.
(författare)
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Effect of Agricultural activities on Groundwater Vulnerability: Case Study of Halabja Saidsadiq Basin, Iraq
- 2015
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Ingår i: Journal of Environmental Hydrology. - 1058-3912 .- 1996-7918. ; 23:10
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Tidskriftsartikel (refereegranskat)abstract
- Groundwater is one of the main sources of water in Halabja-Saidsadiq Basin of northeast Iraq. It covers an area of 1278 square kilometers with population of about 190,727.In this study, the standard DRASTIC method has been applied to generate a map of groundwater pollution vulnerability of the basin. In addition, two different scenes of landsat Thematic Mapper (TM) were used with the aid of ERDAS IMAGINE software and the GIS technique to prepare digital image classification of the study basin. Supervised classification for level I of USGS was conducted with band combination RGB/742 to prepare The Land Use and Land Cover (LULC) map. The LULC map illustrates that only five classes of land use can be identified these are: barren, agricultural, vegetation, urban and wet land or water body. The LULC map converted to LULC index map. This index map has an additional parameter added to the standard DRASTIC model to map the modified DRASTIC vulnerability in the study basin. Nitrate concentration analysis was selected and added as a pollution indicator to validate this modification. In this study, the nitrate concentration between two different seasons (dry and wet) was analyzed from (30) water wells. The standard vulnerability map of the studied basin classified the basin into four vulnerability index zones: very low (34%), low (13%), moderate (48%) and high (5%). While the combined modification classified the area into five classes: very low (1.17%), low (36.82%), moderate (17.57%), high (43.42%) and very high (1.02%). The results s that the modified DRASTIC model was dramatically superior to the standard model; therefore, the most appropriate method to apply is the combination of standard DRASTIC model with LULC index map. This conclusion is based on the results of nitrate content, as its concentration in the dry season is much lower than in the wet season.
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