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2007 research outputs found
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Flood Simulation Utilizing HEC-HMS and HEC-RAS
No full textThe substantial amount of rainfall leading to runoff in floodplain regions poses hazards to residents within these areas and surrounding zones; consequently, flood simulation is crucial for precise risk evaluation and the formulation of water utilization strategies. In this research, hydraulic and hydrological models, supported by Geographic Information Systems (GIS), were employed to simulate rainfall-runoff mechanisms in Wasit Governorate, central Iraq. A resolution of 30 m Digital Elevation Model (DEM) was supplied by the USGS, geospatially processed, and then imported into the Hydrologic Modeling System (HEC-HMS) at the Hydrologic Engineering Center. The runoff within the research area was estimated using the SCS-CN approach. In order to find the Curve Numbers (CN), a number of datasets were combined, including those pertaining to land use, land cover (LULC), and soil types. The HEC-HMS system was fed CN values obtained from GIS, which varied between 73.95 and 97.61. During the incident in November 2015, the Hydrologic Engineering Center's River Analysis System (HEC-RAS) was utilized to simulate floods using the runoff data resulting from HEC-HMS. Inundation maps were produced using RAS-Mapper within HEC-RAS, depicting flood depth and velocity through the study area. The flood model underwent calibration through comparison of the simulation results with satellite imagery for November 14, 2015. Using CSI, the hydrological factors Ia, Muskingum K, and X, and impervious % were adjusted using sensitivity analysis to achieve the greatest convergence between the model and satellite image. The result of CSI was 88.56%, (HR) was 96.31%, and (FAR) was 8.33%. The validation has been done for the calibrated parameters, and the results were compared with satellite imagery for April 3, 2019. The high level of concordance allowed for the final inundation map to be approved. The importance of measuring runoff for managing water resources effectively and reducing flood risks is highlighted by this study
An Exploration of PPP Infrastructure Projects’ Risks in Supporting Sustainable Development and SDGs
No full textIraq has initiated “Iraq Vision 2030” as a participation in the global efforts to attain sustainable development and the United Nations’ Sustainable Development Goals (SGDs). The private sector engagement in infrastructure development was adopted as a national goal. However, no serious accomplishment has been made. Accordingly, this research was conducted to explore risk factors affecting sustainable development in public-private partnership (PPP) infrastructure projects. 116 risk factors were identified through literature review; for proper assessment, monitoring, controlling, and management, they were classified into two groups. The first group includes risk factors that may appear at a specific stage of the PPP project lifecycle. The second group includes risk factors that may appear at any time along the PPP project lifecycle. A field study has been implemented in two stages; the first stage is an open questionnaire and face-to-face interview with PPP experts to finalize and approve proposed risk lists. The second stage is a closed questionnaire; the mean value was used to rank and identify respondents’ agreement on rating the level of importance of these risk factors supported by nonparametric tests. Findings indicated that the critical-level risks form nearly two-thirds of the overall and first-group risks and more than two-thirds of the second-group risks. Financial and fiscal sustainability concerns form a serious challenge, as they came in at the top of the critical-level risk factors. Overall findings indicate the importance of legislating a PPP law that serves the achievement of “Iraq Vision 2030” national goals and the UN’s SDGs and provides a comprehensive framework that protects citizens’ rights, ensures their well-being, and supports sustainable development
Development of Machine Learning for Debris Flow Event Prediction in a Volcanic Area
No full textThe integration of machine learning (ML) into debris flow prediction in volcanic areas, exemplified by the Gendol River watershed of Mount Merapi, offers transformative potential for hazard mitigation. This study aimed to develop real-time, computationally efficient ML models capable of integrating multi-source data, rainfall intensity of 25 mm/hour linked to 300 cm Debris Flow heights, antecedent precipitation, and geomorphological variables to predict debris flows with actionable lead times. Key objectives included optimizing prediction accuracy, minimizing the false positive rate to 18.2% for "Debris Flow" events, and enhancing model interpretability for deployment in data-scarce volcanic regions. Results demonstrated that ensemble methods and deep learning architecture outperformed traditional models, with Efficient Logistic Regression and Linear SVM achieving an accuracy of 82.35%, and Cosine KNN attaining a prediction speed of 272 observations per second. Critical predictors included temporal rainfall patterns (contributing more than 50% to flow initiation) and ash deposit thickness (with a 70% influence on decision-making). However, challenges persisted: imbalanced datasets of nine training instances for "Debris Flow" events led to misclassification rates of 100% for hybrid events like "Rainfall and Debris Flow," while models like Naive Bayes exhibited instability (accuracy dropping to 50%). Research gaps highlighted data scarcity for high-magnitude events, limited geographic transferability, and the absence of standardized evaluation metrics. Technical limitations included reliance on low-resolution remote sensing data, high computational costs for ensemble models requiring 10 operational cost units, and the opacity of neural networks, which hindered stakeholder trust. Despite these constraints, ML models achieved 85% accuracy in non-event recognition and 76.47% precision in Bagged Trees, offering scalable frameworks for early warning systems. The study highlights the importance of enriched datasets, adaptive algorithms, and interdisciplinary collaboration in transforming volcanic risk management from a reactive approach, ultimately safeguarding vulnerable communities through data-driven, life-saving predictions
Seepage Control in Zoned Earth Dams Using Lime–Fly Ash Treated Sandy Soil
No full textSeepage control is a critical factor in ensuring the stability of earth dams, particularly those constructed with permeable soils. Uncontrolled seepage and increased pore pressures within the dam body are typically associated with instability, internal erosion, and potential failure. This study aims to evaluate the effectiveness of lime–fly ash mixtures in controlling seepage through earth dams constructed with sandy soil, using experimental modelling and numerical simulation. A physical model of a zoned earth dam was built using untreated sandy soil as the control model, along with treated models in which the sandy core was stabilized with progressively higher lime–fly ash proportions. The results of laboratory permeability tests demonstrated significant reductions in hydraulic conductivity with increasing additive content, resulting in delayed steady-state conditions and a reduction of up to 98.2% in seepage rate compared with the control model. Numerical simulations, validated against experimental results (coefficient of determination, R²>0.98), accurately reproduced phreatic lines and seepage rates and were further used to examine the influence of core slope geometry. The results showed that a core slope of 0.75:1 provided nearly equivalent hydraulic performance to that of the baseline 1:1 slope, offering a more cost-effective alternative. These findings highlight the potential of lime–fly ash–sand mixtures as sustainable and cost-efficient alternatives for dam cores, particularly in regions where clay resources are limited
Assessment of Red Sea Shoreline Dynamics Through Satellite Imagery and GIS Analysis
No full textMonitoring and analyzing coastal dynamics is essential due to continuous shoreline changes driven by natural processes and human activities with significant environmental and economic impacts. This study aims to quantitatively assess shoreline change along the Red Sea coast using integrated remote sensing and Geographic Information Systems (GIS) techniques. Multi-temporal satellite imagery from 1980 to 2025 was processed to extract shoreline positions, and shoreline change rates were calculated using the EPR method to determine patterns of erosion and accretion. The study area extends along the northwestern part of Saudi Arabia within the Tabuk region, covering Wadi al Ayn, NEOM Port, and the villages of Al Muwaylih, As Sawrah, Sharma, Al Khuraybah, and Qiyal. The results reveal that erosion rates exceed accretion rates across most shoreline segments during the study period. The average EPR of accretion reached 1.13 m/yr, while erosion recorded a higher magnitude with an average rate of −1.99 m/yr. Spatial analysis showed a total accretion area of 1.634 km² compared to a substantially larger erosion area of 19.624 km². This study lies in providing a comprehensive, long-term spatiotemporal assessment of shoreline dynamics using consistent satellite-based measurements, contributing updated baseline data for coastal management and sustainable development planning in the Red Sea region
Theoretical Enhancement of Point Resistance in Sandy Soils Using Bio-Inspired Cranial Asperity Ratios
No full textThis study aims to enhance the bearing capacity of pile foundations in sandy soils through a bio-inspired approach by modifying Meyerhof’s empirical equation using a cranial correction factor. The adjustment considers the geometric influence of the asperity length–height ratio (L/H 20, 26.67, and 33.33) applied to different pile diameters. The analysis was carried out theoretically by calculating point resistance (Qp) using the modified equation, followed by validation through ANOVA and the nonparametric Mann–Whitney test. The results indicate that an L/H ratio of 20 provides the most significant improvement in Qp, ranging from 11.7% to 465.8% compared to the conventional Meyerhof model, particularly at lower D/B ratios where stress concentration can be optimally mobilized. Larger ratios such as 26.67 and 33.33 also improve capacity, though less effectively than L/H 20, yet still outperform unmodified foundations. The correction factors obtained, ranging from Cᵣ 1.07 to 5.66, demonstrate the substantial contribution of geometric modification to load transfer efficiency. The novelty of this research lies in integrating anisotropic interface properties into the classical Meyerhof model, thereby bridging the gap between isotropic predictions and anisotropic experimental evidence. Accordingly, the developed theoretical framework not only strengthens the basis for calculating pile bearing capacity but also opens new avenues for bio-inspired foundation design that is more efficient and sustainable
Drying Shrinkage of Cement Stone with Superplasticizers of Various Chemical Bases
No full textThe crack resistance of reinforced concrete structures also depends on concrete shrinkage. Therefore, assessing the influence of mix design factors and operating conditions on concrete shrinkage is essential to determine the relationships between shrinkage magnitude and kinetics and variables such as ambient humidity, cement properties, and admixture characteristics. These relationships are important for calculating shrinkage crack resistance and, consequently, the durability of reinforced concrete structures. The widespread use of superplasticizers and other mineral additives in concreting, including new complex modifiers, highlights the need to clarify known relationships and identify new dependencies involving the material and mineralogical composition of cements, the properties of admixtures, concrete mix formulation, and environmental humidity on both the magnitude and kinetics of shrinkage deformations. The purpose of this study is to identify patterns in the development of shrinkage deformations of cement paste depending on the type of cement and superplasticizer, including the influence of dehydration degree, and to propose equations that can be used to calculate the shrinkage crack resistance of reinforced concrete structures. The study includes an analysis of established approaches for evaluating changes in drying shrinkage of cement paste as ambient humidity varies. Experimental investigations were conducted on the drying shrinkage of cement paste as a function of evaporable water content and the chemical basis of superplasticizers. The influence of superplasticizers on both the kinetics and magnitude of the basic shrinkage of cement paste is demonstrated, considering evaporable water content under standard conditions as well as after drying to constant mass at 105 °C. The effect of relative air humidity on the basic shrinkage of cement stone has also been clarified. Furthermore, an equation describing the kinetics of shrinkage of cement pastes and a classification of cements based on shrinkage kinetics are proposed. Finally, the dependence of shrinkage for the studied cements with different superplasticizers on relative air humidity is established
Adaptive Hydrodynamic Modeling for Sustainable Irrigation Management in Tidal Swamp Regions
No full textThe Lalan River functions as the primary water source and plays an important role in supporting irrigation systems and water management in tidal swamp areas. However, water management in this region still faces challenges such as salinity intrusion and unstable water distribution, while conventional approaches applied have not fully considered the hydraulic characteristics and hydrodynamic conditions of the waters. This study aims to analyze the hydrodynamic characteristics of the Lalan River as the main water system in the tidal swamp irrigation area of D.I.R. Karang Agung Hilir, Banyuasin Regency, South Sumatra Province, Indonesia, in order to design an effective water management strategy for agricultural irrigation. The research methods include bathymetry, tidal, current, and salinity measurements. Hydrodynamic modeling was applied to analyze aquatic phenomena, including flow dynamics and salinity distribution patterns in tidal swamp areas. The hydrodynamic model was calibrated and validated using field data with a Root Mean Square Error (RMSE) value of 0.170 m to ensure the reliability of the simulation. The analysis results show that the application of a one-way flow system can significantly reduce salinity, from around 2–5 ppt in the old system to around 1–2 ppt during high tide and below 0.5 ppt during low tide, or a reduction of up to ±60%. This reduction allows river water to be used more effectively for agricultural irrigation. The novelty of this research lies in the adaptive hydrodynamic approach based on seasonal hydrological conditions as a foundation for designing sustainable water management systems in tidal swamp areas according to the hydrotopography of the region
An Experimental Study on Web Hardening Technology Using Encasement by RPC and Lacing Reinforcement
No full textOver the past ten years, cold-formed steel two-channel sections featuring edge-stiffened castellated cellular web apertures have been developed and are now widely used in New Zealand. Previous research on vertical compression has shown that using edge-stiffened web openings in these channel sections increases their vertical load capacity. Subsequent studies expanded to include hexagram web holes; however, the literature still lacks investigations on the effect of applied vertical pressure on web openings in two-channel sections with perforated webs. This research addresses that gap. The aim of this study is to evaluate the structural response of symmetrical castellated two-channel (2C) sections. Six specimens of castellated 2C beams made of cold-formed steel and encased in reactive powder concrete with diagonal reinforcement on both sides were examined. The concrete encasement and reinforcement enhanced the beam’s resistance to buckling, bending, and both horizontal and vertical shear, and also improved joint performance. Two concentrated loads were applied at the beam center to investigate the structural behavior of each specimen. The results showed that the presence of a joint gap enhanced load resistance. The ultimate load increased by 6.75% compared with the reference specimen SCB2C-rLG20% in G3, by 30.86% compared with SCB2C-rL in G2, and by 1064.73% compared with SCB2C/R1 in G1. The specimen with a 30% gap demonstrated the best load capacity and the highest ductility compared with the reference specimen and the other specimens
Comparative Life Cycle Assessment of Carbon Fiber and Nano-Silica Modified Asphalt Mixtures
No full textIn recent years, several studies have focused on enhancing the performance of asphalt mixtures using various additives; however, the environmental implications of these modifications have received limited attention. Accordingly, this study aims to evaluate the environmental impacts of asphalt mixtures incorporating carbon fiber (CF) and nano silica (NS) using the Life Cycle Assessment (LCA) methodology. In the current study, four mixtures were modelled and analyzed using SimaPro software: conventional asphalt mix (CAM), carbon fiber asphalt mix (CFAM), nano silica asphalt mix (NSAM), and carbon fiber–nano silica asphalt mix (CFNSAM). The assessment included the production cycle from raw material extraction to wearing surface installation, integrating laboratory performance data with the Ecoinvent v3.6 inventory. Results indicated that CAM exhibited the lowest environmental burden, whereas CFNSAM showed the highest impact resulting from the considerable energy inputs associated with carbon fiber fabrication. NSAM offered a balanced outcome, with moderate environmental impacts and satisfactory mechanical performance, positioning it as a more sustainable alternative. Overall, nano silica modification demonstrates promising potential for eco-efficient pavement applications