Papers by Prof. Dr. Hamza F Gabriel
Hamza Farooq Gabriel, PhD is associated with NUST ABSTRACT: Disputes have detrimental effects on ... more Hamza Farooq Gabriel, PhD is associated with NUST ABSTRACT: Disputes have detrimental effects on project leading to cost overruns, delays, poor quality of work and intangible losses to working relationship among the project participants. This study identifies the root causes of disputes in construction industry by an extensive literature review and a survey in the Pakistani construction industry. A three step content analysis approach has been adopted to collect and analyze the research papers published during the period 1993-2015. A total of 33 papers were found to be relevant. From these papers, 52 factors were found, out of which 31 have been shortlisted for this study. They were subjected to a screening process to determine the top five causes of disputes which are delays in payments, change orders, quality of works, delays in work and contractual anomalies. Based on the factors identified through literature review, a survey was conducted in Pakistani construction industry. The ...
Satellite-based precipitation (SBP) is emerging as a reliable source for high-resolution rainfall... more Satellite-based precipitation (SBP) is emerging as a reliable source for high-resolution rainfall estimates over the globe. However, uncertainty in SBP is still significant, limiting their use without evaluation and often without bias correction. The bias correction of SBP remained a challenge for atmospheric scientists. In this study, the performance of six SBPs, namely, SM2RAIN-ASCAT, IMERG, GsMap, CHIRPS, PERSIANN-CDS and PERSIANN-CSS in replicating observed daily rainfall at 364 stations over Peninsular Malaysia was evaluated. The bias of the most suitable SBP was corrected using a novel machine learning (ML)-based bias-correction method. The proposed bias-correction method consists of an ML classifier to correct the bias in estimating rainfall occurrence and an ML regression model to correct the amount of rainfall during rainfall events. The performance of different widely used ML algorithms for classification and regression were evaluated to select the suitable algorithms. IME...
Introduction: Wastewater treatment plants are used to reduce pollution depending upon their effec... more Introduction: Wastewater treatment plants are used to reduce pollution depending upon their effectiveness, treatment-efficiency, available-land, energy-sources, topography, climate and prevailing-winds, seasonal and climatic variations, and principal-cost. Integrated constructed wetlands (ICWs) are diversely used for wastewater treatment because of their increased treatment efficiency. Purpose of the study: This study comprises of large-scale-ICW located at NUST Islamabad, Pakistan. Purpose of study was to monitor and identify the nutrient removal over the period of six month from October 2018 to March 2019. Material and methods: Samples were taken from each compartment of HSSF-CW (Horizontal Sub-Surface Flow Constructed Wetland) and FILTER technology (Filtration and Irrigated cropping for Land Treatment and Effluent Reuse) of treatment system. Different parameters including EC(Electrical conductivity), NO3 (Nitrate), NO2 (Nitrite), TKN (Total Kjeldahl Nitrogen), PO43- (Phosphate) w...
Journal of Engineering and Applied Sciences , University of Engineering and Technology, Peshawar, 2003
For the solution of groundwater problem many types of models are used, but electrical analogue mo... more For the solution of groundwater problem many types of models are used, but electrical analogue model is preferred due to its close response with its prototype hydrological system. This model is easy to construct and is reusable. In the model voltage is correlated to groundwater head, electric current lo flow and capacitance to ground water storage. The analogy of the model is derived based on Kirchhoffs law and Finite difference form of Laplace equation. The network is consisting of square and rectangular meshes. Scaling factor for voltage and resistors are selected. All the equipments needed for assembling the model are prepared. Terminal strips and their connectivity are checked. Calculated resistors with accurate values after cutting and molding are inserted in the terminal strips and desired section is completed. A network of resistors in X and Z direction is used to represent the aquifer. Two stabilized power supply are used to provide the electrical potential. The worst condit...
Environmental Earth Sciences, 2021
Regional climate change (CC) and land use changes (LUCs) can significantly influence the hydrolog... more Regional climate change (CC) and land use changes (LUCs) can significantly influence the hydrological processes at watershed scale. Different studies have investigated the impact of climate change in the Indus Basin. However, there is a need to investigate the impact of environmental changes on the regional hydrology over a complex topographic region. This study quantitatively assesses the relative contributions of CC and LUC on runoff alterations across Gilgit watershed by using multivariable calibration approach using the Soil and Water Assessment Tool (SWAT). Mann–Kendall (MK) and Pettitt tests are applied to identify the trends and changes in runoff and climatic variables during 1985–2013. The supervised classification is performed to acquire land use maps and other quantitative details required for the analyses. Moreover, Indicators of Hydrologic Alterations (IHA) analyses were performed for the first time in the Gilgit watershed to investigate the impact of CC and LUCs during the pre- and post-impact periods. The results demonstrated that precipitation, temperature, and runoff of the Gilgit watershed presented significant increasing trends. The change point using Pettitt test is depicted in 1999, 1995, and 1998, respectively. The mean annual increasing rate of precipitation, temperature, and runoff is 4.92 mm/year, 0.04 °C/year, and 2.60 m3/year, respectively. SWAT model performed well and the relative attributed contribution of CC to runoff change is 97.22% and it is 2.78% for LUC. The IHA results showed that runoff has significantly increased in post-impact (1999–2013) as compared to pre-impact (1985–1998), which was further confirmed by analyzing the IHA results using percent bias (PBIAS). Significant overestimation of runoff (higher runoff in post-impact period) was observed in the wet (maximum runoff) season. This study demonstrated that the high contribution of CC to runoff change is mainly due to the change in climate variables and global warming trends.
Pure and Applied Geophysics, 2021
Variations in the rate of urbanization directly impact groundwater levels and quality. Therefore,... more Variations in the rate of urbanization directly impact groundwater levels and quality. Therefore, the present study examines the relationship between changes in land-use and land-cover (LULC) and groundwater drawdown in Rawalpindi, Pakistan. Landsat images, i.e., Operational Land Imager (OLI), Thematic Mapper (TM), and Enhanced Thematic Mapper Plus (ETM+), were downloaded for the years 1991, 1997, 2007, 2010, and 2017. The study area was classified using the normalized difference vegetation index (NDVI) and normalized difference built-up index (NDBI) to create three classes, i.e., urban area, vegetation, and barren land. The groundwater level in the study area for the year 2017 was obtained using an electrical resistivity survey (ERS) with a Schlumberger configuration. The data obtained were interpreted using IX1D iteration software. The results of NDBI and NDVI showed that the urban area increased by 37.89% during the period 1991–2017, at the expense of vegetation. Similarly, the groundwater level was found to decrease at a rate of 1.38 m per annum. If the same trend prevails, the groundwater level will decrease to approximately 160 m from the natural ground surface by the end of this century. The results of the present study may be used for the formulation of policy and proper planning prior to any major developmental project to control the impact of LULC changes on water resources in the future.
Hydrological Sciences Journal, 2021
ABSTRACT This study evaluates the spatial and temporal performance of the Climate Hazard Group In... more ABSTRACT This study evaluates the spatial and temporal performance of the Climate Hazard Group InfraRed Precipitation Satellite (CHIRPS) against Tropical Rainfall Measuring Mission (TRMM) Multi-Satellite Precipitation Analysis (TMPA) 3B42/3B43 v. 7 and Global Precipitation Measurement (GPM)-based Integrated Multi-Satellite Retrievals for GPM (IMERG V06), from 2000 to 2013. Several statistical metrics were used to assess the performance of CHIRPS over the Indus Basin, and its hydrological utility is also assessed using the Soil and Water Assessment Tool (SWAT). The Gilgit and Soan basins were selected for hydrological modelling. The results demonstrate the spatial and temporal dependency of CHIRPS, i.e. better performance was observed in the Lower Indus Basin (LIB) while poor performance was observed in the Upper Indus Basin (UIB). The hydrological assessment of CHIRPS revealed poor performance (overestimation of streamflow) across the Gilgit Basin during both calibration and validation periods. Satisfactory to good performance was obtained across the Soan Basin.
Theoretical and Applied Climatology, 2020
The main objective of this study is the flood modeling of the River Jhelum Basin in the Jammu and... more The main objective of this study is the flood modeling of the River Jhelum Basin in the Jammu and Kashmir using the Integrated Flood Analysis System (IFAS) hydrological model. The region having an area of 33,000 km2 has a limited rain gauge coverage. The data inaccessibility is accentuated due to the mountainous topography, glaciers, and remote areas. This research makes innovative use of the Asian Precipitation - Highly-Resolved Observational Data Integration Towards Evaluation (APHRODITE) dataset to overcome the data scarcity for the basin. For flood modeling, a regionalized approach was adopted, whereby the four main tributaries of the River Jhelum Basin were separately modeled. The parameters, thus, determined, were later used in the modeling of the River Jhelum, the main river of the basin. The model was calibrated on the medium-high flood of 2010 and validated on the very high flood of 2014, obtaining good results as indicated by Nash–Sutcliffe Model Efficiency Coefficient (NSE) of 0.77. Later, the model was executed using the Global Satellite Mapping of Precipitation (GSMaP). It performed adequately for the high flood event of 2014, while for the flood of 2010, it gave poor results. Besides, this study also demonstrates the efficacy of a new generation of computer models that work by accessing the free global datasets available on the web for hydrological modeling.
Irrigation and Drainage, 2020
A significant amount of water is lost in canals due to seepage. This could be saved to irrigate b... more A significant amount of water is lost in canals due to seepage. This could be saved to irrigate barren land. This article presents the measured seepage data by the inflow-outflow method on seven so-called concrete-lined distributary canals in Punjab, Pakistan. A special feature of the inflow-outflow method is the relatively long lengths of the canal reaches (9 to 5 km), which is the longest one could find in the literature so far. The seepage in canals is also calculated using five empirical formulae. The results show that the Swamee and the Punmia formulae performed admirably with mean percent errors of −20% and + 19% respectively. Moritz formula stood at +53% while Kostiakov scored +158%. The research also proposed a slight modification in the Swamee formula whereby, instead of the canal width, the surface water width was used in the calculation of the dimensionless variable F. This led to a beneficial effect of bringing down the percent mean error from −42% to −20%. K E Y W O R D S empirical formulae for seepage estimation, inflow-outflow method, lined distributary canals, seepage estimation, seepage loss RĖSUMĖ Une quantité importante d'eau est perdue dans les canaux en raison de l'infiltration. Cela pourrait être économisé pour irriguer les terres stériles. Cet article présente les données d'infiltration mesurées par la méthode entrées/sorties sur sept canaux de distribution dits en béton au Punjab, au Pakistan. Une particularité de la méthode entrées/sorties est la longueur relativement longue des tronçons du canal (9 à 5 km), qui est la plus longue que l'on puisse trouver jusqu'à présent dans la littérature. L'infiltration dans les canaux est également calculée à l'aide de cinq formules empiriques. Les résultats montrent que les formules de Swamee et de Punmia se sont admirablement comportées avec des pourcentages d'erreur moyens de −20% et + 19% respectivement. La formule de Moritz s'établit à + 53% tandis que Kostiakov marque +158%. La recherche a également proposé une légère modification de la formule de Swamee selon laquelle, au lieu de la largeur du canal, la largeur de l'eau de surface a été utilisée dans le calcul de la variable sans dimension F. Cela a
<p&amp... more <p> Increase in frequency of the floods is one of the noticeable climate change impacts. The efficient and optimized flood analysis system needs to be used for the reliable flood forecasting. The credibility and the reliability of the flood forecasting system is depending upon the framework used for its parameter optimization. Comprehensive framework has been presented to optimize the input parameters of the computationally extensive distributed hydrological model. A large river basin has the high spatio-temporal heterogeneity of aquifer and surface properties.  Estimating the parameters in fully distributed hydrological model is a challenging task. The parameter optimization becomes computationally more demanding when the model input parameters (30 to 100 even greater) have multi-dimensional parameter space, many output parameters which make the optimization problem multi-objective and large number of model simulations requirement for the optimization. Aforementioned challenges are met by introducing the methodology to optimize the input parameters of fully distributed hydrological model, following steps are included (1) screening of the parameters through Morris sensitivity analysis method in different flow periods, so that optimization would be performed for sensitive parameters, different scalar output functions are used in this regard (2) to emulate the hydrologic response of the dynamic model, surrogate models or meta-models are used (3) sampling of parameters values using the optimized ranges obtained from the meta-models; the results are evident that the parameter optimization using the proposed framework is efficient can be effectively performed.  The effectiveness and efficiency of the proposed framework has been demonstrated through the accurate calibration of the model with fewer model runs. This study also demonstrates the importance and use of scalar functions in calculating sensitivity indices, when the model output is temporally variable. In addition, the parameter optimization using the proposed framework is efficient and present study can be used as reference for optimization of distributed hydrological model. </p><p> </p><p><strong>Keywords: </strong>Calibration, parameter ranking, Sensitivity analysis, Hydrological modeling, optimization</p>
International Journal of Environmental Research and Public Health, 2020
Water is essential for life, agriculture, and industrialization; however, a rapid increase in pop... more Water is essential for life, agriculture, and industrialization; however, a rapid increase in population is constantly causing water scarcity and pollution in Pakistan. Mining activities produce the potential toxic element (PTE) accumulation, which lead to unnatural enrichment, ecological pollution, and environmental degradation. The ecological resources impeded by the PTEs cause serious abnormalities in the population through dermal contact, inhalation, and digestion. Mining induced anthropogenic activities are well-known causes of contamination of ecological resources. The produced effluents have drastic effects by changing the physical, chemical, and biological properties of the concerned resources. The Central Indus Basin is a well-known coal regime, where more than 160 mines are active at present. The samples that were collected from the mine water, groundwater, surface water, and the soil were analyzed by atomic absorption and elemental determination analysis (EDA) for an asse...
Smart and Sustainable Built Environment, 2019
Purpose The formal application of project risk management (PRM) in green building projects is sti... more Purpose The formal application of project risk management (PRM) in green building projects is still an emergent part of project management. The purpose of this paper is to provide a conceptual PRM framework that increases the probability of success in green building projects by minimizing unexpected events. Design/methodology/approach This paper interprets the related literature and uses the opinion of green building experts. It exposes some pertinent elements needed for structuring the PRM framework and suggests some mitigation actions for high-ranked risks. It also performs ex-post analysis on a case study to practically validate the proposed framework. Findings It is found that high initial cost, lack of experienced contractors and subcontractors, consideration of lifecycle inflation and experience in green building project management are the most significant risks. To address them, the framework proposes a rigorous selection of contractors, provision of financial incentives from...
Arabian Journal for Science and Engineering, 2019
Aims: This study was designed to investigate the plasmid bearing multiple antibiotic resistant ba... more Aims: This study was designed to investigate the plasmid bearing multiple antibiotic resistant bacteria from different aquatic sources.
Journal of Construction in Developing Countries, 2018
The construction industry consumes a large part of raw material and global energy, and produces h... more The construction industry consumes a large part of raw material and global energy, and produces huge amount of solid waste. It is established that waste generated by construction processes has significant negative impact on the economy and environment. Effective waste management helps in reducing quantity of wastes and making a substantial contribution towards sustainable development and cost control. Based on a benchmarking approach, this research quantifies the material wastage and its causes in different types of building projects. In a waste diagnostic survey, 38 project sites were surveyed. Results revealed that bricks, tiles, and plaster from mortar are the most wasteful materials, and improper worker's skills, poor supervision, and lack of management the most significant causes. Buildings with substantial architectural works tend to generate maximum amount of waste while contractor size does not affect waste generation rate. Based on expert opinion, practical recommendations are given to control material waste. The findings offer a new perspective on sustainable construction by correlating building types with waste generation, as contribution to the existing body of knowledge. It will lead the construction managers to better understand the actual situation of construction waste and devise control measures.
Earth Systems and Environment, 2018
Heat waves are one of the extreme weather events affecting as many people as with other climatic ... more Heat waves are one of the extreme weather events affecting as many people as with other climatic hazards such as droughts and floods. Due to rise in global temperatures, the occurrences of heat waves are likely to exacerbate in many regions in future. The projections for future heat waves over Pakistan are analyzed in this study. The heat waves calculation has been done using the latest NASA Earth Exchange Global Daily Downscaled Projections (NEX-GDDP) data set which composed of 21 Global Climate Models (GCMs) statistically downscaled at 0.25° × 0.25° spatial resolution. The heat waves analysis is done with ensemble modelling approach and using two definitions of heat waves: the Heat waves Duration Index (HWDI) and fixed method approach. Two climate change scenarios; RCP4.5 and RCP8.5 are used for investigating future heat wave projections. The historical heat waves are calculated from 1976-2000 and future projected changes are analyzed in three 25 year time spans:
Hydrological Sciences Journal, 2018
The major flood of 2014 in the two eastern, transboundary rivers, the Jhelum and Chenab in Punjab... more The major flood of 2014 in the two eastern, transboundary rivers, the Jhelum and Chenab in Punjab, Pakistan was simulated using the two-dimensional rainfall-runoff model. The simulated hydrograph showed good agreement with the observed discharge at the model outlet and intervening barrages, with a Nash-Sutcliffe efficiency of 0.86 at the basin outlet. Further, simulated flood inundation extent showed good agreement with the MODIS imagery with a fit (%) of 0.87. For some affected areas that experienced short-duration flooding, local housing damage data confirmed the simulated results. Beside the rainfallrunoff and flood inundation modelling, parameter sensitivity analysis was undertaken to identify the influence of various river and floodplain parameters. The analysis showed that the river channel geometric parameters and the roughness coefficients exerted primary influence over the flood extent and peak flow.
Advances in Science, Technology and Engineering Systems Journal, 2016
Journal of Legal Affairs and Dispute Resolution in Engineering and Construction, 2017
AbstractAlmost all construction projects face delays resulting in extension of time (EOT) or liqu... more AbstractAlmost all construction projects face delays resulting in extension of time (EOT) or liquidated damages, depending upon which of the two parties absorbs the responsibility as per terms of t...
KSCE Journal of Civil Engineering, 2017
This technical note studies the supercritical junction flow occurring at the right-angled conflue... more This technical note studies the supercritical junction flow occurring at the right-angled confluence of four equal-width channels in which two upstream channels carry flow towards the junction. The note seeks to investigate, firstly, the pertinence of a 2D shallow water equation model to reproduce the typical flow structures at the junction. The second objective is to build a computationally efficient model with more resolution applied at critical point i.e. junction and less in areas where the flow is primarily 1D i.e. channels and compare such model, named, 'sparse' with a uniformly meshed model regarding solution accuracy and computational efficiency. The results indicate that the sparse model is able to reproduce typical flow structures appearing at the channel junction in an adequate manner. The discharge distribution is fairly well predicted. The jump angles are almost the same in the two models as well as the location and size of the recirculation zones and the flow depth super-elevation areas. However, the two models diverge in the prediction of very small depths in the recirculation zone where the sparse model overestimates the depths. As regards, computational efficiency, the sparse model is found to be 61% more efficient than the uniform mesh model.
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Papers by Prof. Dr. Hamza F Gabriel