Current Organizations / Institutes

The organizations/institutes from the scholar's latest article

Previous Organizations / Institutes

The organizations / institutes from the scholar's other articles in the past ten years


Karrar Mahdi has a total of 45 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Open Access

    Correction: Gaznayee et al. Integrating Remote Sensing Techniques and Meteorological Data to Assess the Ideal Irrigation System Performance Scenarios for Improving Crop Productivity. Water 2023, 15, 1605

    by Heman Abdulkhaleq A. Gaznayee, Sara H. Zaki, Ayad M. Fadhil Al-Quraishi, Payman Hussein Aliehsan, Kawa K. Hakzi, Hawar Abdulrzaq S. Razvanchy, Michel Riksen, Karrar Mahdi

    The journal’s Editorial Office and Editorial Board are jointly issuing a resolution and removal of the Journal Notice linked to this article

  • Open Access

    Comparison of Subsoiler Plow Performance using Different Vibration Wings Designs

    by Hussein Alaa Aldin Al-Aabagh, Yousif Yakoub Hilal, Karrar Mahdi

    The study aims to manufacture and develop the vibrating wings for the subsoil plough and to evaluate the performance of the locally manufactured wings and their impact on the stability of the driver’s seat, noise, slipping, and fuel consumption. Three factors were used to evaluate the performance of the subsoiler plough, the factors including the types of vibrating wings, traditional vibrating wings (TD35) and two designs of locally manufactured wings (ND35 and ND45), and two angles of penetration of 40° and 50° at a speed of wings vibration of 60 and 120 m·s −2 . The experiment was analysed using a randomised complete block design with a split-plot design and Duncan’s multiple range test at the 0.05% and 0.01% probability levels. The results showed that the stability of the driver’s seat and noise in TD35 was higher than that in both ND35 and ND45, with higher values of approximately 2.450 m·s −2 and 86.4 dB. The vibration and noise values are considered higher than those specified by international organisations that protect farmers in agricultural work (European Parliament Directive 2003/10/EC). Moreover, ND35 recorded the lowest slipping and fuel consumption results, estimated at 7.948% and 4.563 l·h −1 at the penetration angles of 50° and 40°, respectively. Finally, the results showed that the stability of the driver’s seat, noise, slipping, and fuel consumption were higher at TD35; simultaneously, the best results were achieved as the solution for the problem when using ND35 in the 40° and 50° penetration angles with both wings vibrations. The conclusion is that local vibrating wing designs reduced all the characteristics studied.


  • Open Access

    GIS-based multi-criteria decision making for identifying rainwater harvesting sites

    by Waqed H. Hassan, Karrar Mahdi, Zahraa K. Kadhim


  • Retracted
    Open Access

    RETRACTED: Optimal rainwater harvesting locations for arid and semi-arid regions by using MCDM-based GIS techniques

    by Waqed H. Hassan, Karrar Mahdi, Zahraa K. Kadhim


  • Open Access

    Trends, forecasting and adaptation strategies of climate change in the middle and west regions of Iraq

    by Waqed H. Hassan, Basim K. Nile, Zahraa K. Kadhim, Karrar Mahdi, Michel Riksen, Rifqa F. Thiab

    Climate change has placed considerable pressure on the residential environment, agricultural, and water supplies in different areas of the world, especially arid places such as Iraq. Iraq is one of the five most vulnerable countries in the world to climate change, where it has been encountering extremes heat waves during the most recent decades resulted in drought, desertification, and rivers dried up, which led to thousands of hectares to turn dry and yellow. This study aims to investigate the trends of climate change in the middle and western regions of Iraq and future expectations. The daily maximum temperature, minimum temperature, and precipitation are downscaled using the Long Ashton Research Station Weather Generator (LARS-WG) model. Five General Circulation Models (GCMs) from Coupled Model Intercomparison Project Phase 5 (CMIP5) are employed for three future periods: the near future (2021–2040), medium future (2051–2070), and far future (2081–2100), based on two scenarios of the Representative Concentration Pathways (RCP4.5 and RCP8.5) for four selected meteorological stations representing the study area. The outcomes of the calibration and validation of the model supported its skill and reliability to downscale precipitation and temperature time series for statistical indices (R2, RMSE and MBE) ranging between (0.894–0.998), (0.1270–1.9274) and (− 0.6158 to 0.0008), respectively. The results showed that the average minimum and maximum annual temperatures will increase at all selected stations across the three future periods by between 0.94 and 4.98 °C by the end of the twenty-first century. Annual changes in precipitation tend generally towards increase for the study area by average (6.09–14.31%) for RCP4.5 and (11.25–20.97%) for RCP8.5 Compared to the historical data (1990–2020). These findings can contribute to become more acquainted with the effects of climate change on the environment and encourage managers and planners to come up with plans for mitigating and adapting to these effects. They can also serve as a guide for future management of water and agricultural resources in the study region.


  • Open Access

    Integrating Remote Sensing Techniques and Meteorological Data to Assess the Ideal Irrigation System Performance Scenarios for Improving Crop Productivity

    by Heman Abdulkhaleq A. Gaznayee, Sara H. Zaki, Ayad M. Fadhil Al-Quraishi, Payman Hussein Aliehsan, Kawa K. Hakzi, Hawar Abdulrzaq S. Razvanchy, Michel Riksen, Karrar Mahdi

    To increase agricultural productivity and ensure food security, it is important to understand the reasons for variations in irrigation over time. However, researchers often avoid investigating water productivity due to data availability challenges. This study aimed to assess the performance of the irrigation system for winter wheat crops using a high-resolution satellite, Sentinel 2 A/B, combined with meteorological data and Google Earth Engine (GEE)-based remote sensing techniques. The study area is located north of Erbil city in the Kurdistan region of Iraq (KRI) and consists of 143 farmer-owned center pivots. This study also aimed to analyze the spatiotemporal variation of key variables (Normalized Difference Moisture Index (NDMI), Normalized Difference Vegetation Index (NDVI), Precipitation (mm), Evapotranspiration (ETo), Crop evapotranspiration (ETc), and Irrigation (Hours), during the wheat-growing winter season in the drought year 2021 to understand the reasons for the variance in field performance. The finding revealed that water usage fluctuated significantly across the seasons, while yield gradually increased from the 2021 winter season. In addition, the study revealed a notable correlation between soil moisture based on the (NDMI) and vegetation cover based on the (NDVI), and the increase in yield productivity and reduction in the yield gap, specifically during the middle of the growing season (March and April). Integrating remote sensing with meteorological data in supplementary irrigation systems can improve agriculture and water resource management by boosting yields, improving crop quality, decreasing water consumption, and minimizing environmental impacts. This innovative technique can potentially enhance food security and promote environmental sustainability.


  • Open Access

    Rainwater Catchment System Reliability Analysis for Al Abila Dam in Iraq’s Western Desert

    by Ammar Adham, Rasha Abed, Karrar Mahdi, Waqed H. Hassan, Michel Riksen, Coen Ritsema

    Rainwater Catchment System Reliability (RCSR) is the chance that a system will deliver the required water for an interval of time. Rainwater Harvesting (RWH) is gaining popularity as a potential alternative water source for household or agricultural use. The reliability of the Al Abila dam in the western desert of Iraq was analyzed using a water budget simulation model and two explanations of reliability, time-based reliability, and volumetric reliability. To evaluate rainwater harvesting system performance, comprehensive software utilizing a method for everyday water balance using data from 20 years of daily rainfall. According to the findings, volumetric reliability, and for the three climate scenarios (wet, average, and dry year), increased as the storage volume increased until a threshold accrued on the storage capacity of 11.7 × 105 m3. While time-based reliability shows an increase up to a storage volume of 10.2 × 105 m3. Volumetric reliability of roughly 34–75% may be achieved, while only 14–28% time-based reliability may be achieved. Water saving efficiency decreases with increasing demand fraction, while the runoff coefficient has no significant influence on water effectiveness. While growing storage fraction value increases the effectiveness of water conservation and the value of the runoff coefficient influences the water saving efficiency. For both cases, water saving efficiency for the dam does not reach 50%. Using daily rainfall data, the technique given in this paper might be applied to predict water savings and the RWH systems’ reliability in different arid and semi-arid areas.


  • Open Access

    Effect of Artificial (Pond) Recharge on the Salinity and Groundwater Level in Al-Dibdibba Aquifer in Iraq Using Treated Wastewater

    by Waqed H. Hassan, Abdulnoor A. J. Ghanim, Karrar Mahdi, Ammar Adham, Fatima A. Mahdi, Basim K. Nile, Michel Riksen, Coen Ritsema

    Groundwater is one of the most important water resources in Iraq, so efficient management of storage, recharge, and consumption rates is required, for maintaining the sustainability of groundwater supplies. Some of the most valuable methods for ensuring the long-term sustainability of groundwater aquifers are those that provide artificial recharge. This study was conducted to determine the effect of artificial recharge on groundwater levels and quality in Iraq’s Dibdibba unconfined aquifer, utilizing groundwater modeling system software (GMS). Reclaimed water (tertiary treatment) from Kerbala’s central wastewater treatment plant (WWTP) was used as raw water to recharge the aquifer. The effects of this artificial recharge were determined using built-up groundwater flow (MODFLOW) and dissolved transport (MT3DMS) simulation models. Model calibration and validation were implemented based on groundwater monitoring data from 2016 to 2017. The model matched observed elevations at R2 = 0.96 for steady state and R2 = 0.92 in transient state simulations. After the 3D numerical model was calibrated and validated, two scenarios were explored based on the daily production of 5000 and 10,000 m3/d from Karbala’s WWTP. The results indicated that the pumping of the treated wastewater through the pond would increase water levels by more than 20 cm for more than 78.2 and 110 km2 for pumping rates of 5000 and 10,000 m3/day, respectively. More than 40 km2 would be added (reclaimed) to the agricultural areas in the region as a result of the use of artificial recharge using a pond. Groundwater quality was also improved, as the TDS decreased by more than 55%, down to 1900 ppm, and the EC decreased by more than 68%, down to 1500 µ.S/cm. The findings of this study can assist decision-makers in developing strategies to reduce water scarcity and adapt to climate change.


  • Open Access

    Drought Severity and Frequency Analysis Aided by Spectral and Meteorological Indices in the Kurdistan Region of Iraq

    by Heman Abdulkhaleq A. Gaznayee, Ayad M. Fadhil Al-Quraishi, Karrar Mahdi, Joseph P. Messina, Sara H. Zaki, Hawar Abdulrzaq S. Razvanchy, Kawa Hakzi, Lorenz Huebner, Snoor H. Ababakr, Michel Riksen, et al.

    In the past two decades, severe drought has been a recurrent problem in Iraq due in part to climate change. Additionally, the catastrophic drop in the discharge of the Tigris and Euphrates rivers and their tributaries has aggravated the drought situation in Iraq, which was formerly one of the most water-rich nations in the Middle East. The Kurdistan Region of Iraq (KRI) also has catastrophic drought conditions. This study analyzed a Landsat time-series dataset from 1998 to 2021 to determine the drought severity status in the KRI. The Modified Soil-Adjusted Vegetation Index (MSAVI2) and Normalized Difference Water Index (NDWI) were used as spectral-based drought indices to evaluate the severity of the drought and study the changes in vegetative cover, water bodies, and precipitation. The Standardized Precipitation Index (SPI) and the Spatial Coefficient of Variation (CV) were used as meteorologically based drought indices. According to this study, the study area had precipitation deficits and severe droughts in 2000, 2008, 2012, and 2021. The MSAVI2 results indicated that the vegetative cover decreased by 36.4%, 39.8%, and 46.3% in 2000, 2008, and 2012, respectively. The SPI’s results indicated that the KRI experienced droughts in 1999, 2000, 2008, 2009, 2012, and 2021, while the southeastern part of the KRI was most affected by drought in 2008. In 2012, the KRI’s western and southern parts were also considerably affected by drought. Furthermore, Lake Dukan (LD), which lost 63.9% of its surface area in 1999, experienced the most remarkable shrinkage among water bodies. Analysis of the geographic distribution of the CV of annual precipitation indicated that the northeastern parts, which get much more precipitation, had less spatial rainfall variability and more uniform distribution throughout the year than other areas. Moreover, the southwest parts exhibited a higher fluctuation in annual spatial variation. There was a statistically significant positive correlation between MSAVI2, SPI, NDWI, and agricultural yield-based vegetation cover. The results also revealed that low precipitation rates are always associated with declining crop yields and LD shrinkage. These findings may be concluded to provide policymakers in the KRI with a scientific foundation for agricultural preservation and drought mitigation.