International Journal of Hydrology Science and Technology (6 papers in press)

Regular Issues

• Application of the HEC-HMS model for runoff simulation in Al-Sanober Watershed, Syria  
  by Amer Qousai Aldarwish, Ruba Dahham Alsaeed, Mais Mayassah, Shaymaa Alsamia, Edina Koch 
  Abstract: Reliable runoff modeling is essential for water-resource planning in seasonal, ungauged basins. This study developed an HEC-HMS model for the 252 km2 AL-Sanober watershed, using SCS-CN for losses (with GCN250 curve numbers), SCS unit hydrograph for rainfallrunoff transformation, and Muskingum routing for channel flow. Curve numbers were adjusted for slope with Hangs equation (2006) and an initial abstraction ratio = 0.05. The model was calibrated and validated with two observed storm events and evaluated using RSR, NSE, PBIAS, and R2. Slope-adjusted CN inputs produced accurate simulations of runoff volume and peak discharge. A Type II 24-h temporal distribution was confirmed via statistical indicators and trial-and-error for hypothetical design storms, enabling derivation of runoff curves, coefficients, and return-period estimates. Mean annual runoff (2008-2015) was 373 mm, equivalent to ~85 million m3. Sensitivity analysis showed peak discharge responds more strongly to CN changes than to rainfall increases, emphasising watershed-specific CN refinement.
  Keywords: HEC-HMS; GCN250; slope-adjusted CN; initial abstraction ratio; runoff hydrograph.
  DOI: 10.1504/IJHST.2026.10077391
   
  
• Enhanced energy dissipation in modified stepped weirs: a hydrodynamic investigation  
  by Ghufran Faris Alrahhawi, Ahmed A.A. Alkattan, Ahmed Y. Mohammed 
  Abstract: Energy dissipation is vital for safeguarding stepped weirs and reducing stilling basin costs. Moving beyond traditional external add-ons, this research investigates internal flow-path modifications to enhance turbulence. Experimental results reveal that models M2 and M3 improved dissipation by 58.12% and 50%, respectively, compared to the standard M1 design. The study demonstrates that efficiency is closely tied to step geometry relative to critical depth, leading to the development of a new empirical formula () for predictive modelling. These findings offer a practical approach to optimising dam safety and flood control by significantly downsizing downstream structures while maintaining high hydraulic performance.
  Keywords: energy dissipation; stepped weirs; hydraulic structures; geometric parameters; dimensional analysis; flood control; empirical model; dam engineering.
  DOI: 10.1504/IJHST.2026.10078270
   
  
• Multi footprint evaluation of Andean hydropower integrating nature-positive water footprint, life-cycle assessment and eco-hydrological resilience in the Mantaro Basin  
  by Araujo Reyes Luis-Donato, Percy Cesar Estrada-Ayre, Percy Eduardo Basualdo-Garcia, Russbelt Yaulilahua-Huacho, Anthony Enriquez-Ochoa, Syntia Porras-Sarmiento, Miriam Liz Palacios-Much 
  Abstract: The scoping review focuses on the combination of the nature-positive water footprint framework and life-cycle assessment (LCA) to assess the sustainability of hydropower production in the Mantaro River basin, one of the main energy sources of the Central Andes. Hydropower in the basin is a source of electricity in Peru and it is placing more strain on fresh water and high altitude ecosystems. This review is a synthesis of multidisciplinary (hydrology, energy systems, and ecosystem science) evidence that was published in 20102025 in accordance with the PRISMA-ScR guidelines. The analysis reveals significant trade-offs between water, land, and carbon footprints and reflects on the eco-hydrological limits and governance lapses which limit nature-positive outcomes. Combining NP-WF and LCA presents prospects of basin-based management policies that optimise the renewable energy production, water-usage efficiency, and biodiversity resilience. The results indicate the necessity of transdisciplinary models to direct the low-carbon energy shifts in the ecologically delicate mountain systems.
  Keywords: water-energy nexus; hydropower sustainability; nature-positive water footprint; life-cycle assessment; Mantaro River basin; MRB; Andean basins; renewable energy transitions.
  DOI: 10.1504/IJHST.2026.10078271
   
  
• Advancing streamflow prediction with Kolmogorov-Arnold network and LSTM: a comparative analysis  
  by Vipul Santrambhai Varma, Jayantilal N. Patel 
  Abstract: Accurate streamflow forecasting is a prerequisite for integrated water resource management and effective flood mitigation strategies. This study presents a comparative evaluation of the Kolmogorov-Arnold network (KAN) and the long short-term memory (LSTM) model for daily discharge prediction. The novelty of this research lies in its pioneering application of KAN, an innovative architecture based on learnable B-spline activation functions on edges to river discharge forecasting across both regulated (Garudeshwar) and natural (Handia) flow regimes in the Narmada River Basin, India. Utilising longitudinal data from 1974 to 2018, the results demonstrate that KAN achieved higher predictive fidelity than the LSTM benchmark, specifically in regulated environments. Quantitatively, at the Garudeshwar station, KAN achieved a coefficient of determination (R2) of 0.7756 and reduced the root mean square error (RMSE) to 819.11, compared to the LSTMs R2 of 0.6975 and RMSE of 935.34. Furthermore, KAN mitigated the systemic peak-smoothing observed in gated architectures, providing a nearly 44% reduction in overall mean absolute error (MAE), largely attributed to improved accuracy during high magnitude events. Significantly, KAN achieved these results with a parameter count reduction of up to 98%, establishing it as a parsimonious and computationally efficient tool for real-time hydrological forecasting.
  Keywords: streamflow; Kolmogorov-Arnold network; KAN; long short-term memory; LSTM; forecasting; machine learning.
  DOI: 10.1504/IJHST.2026.10078563
   
  
• Optimising water release patterns for sustainable agriculture and ecosystem health: a case study of the Zayandehrud River Basin, Iran  
  by Mohammad Jamali, Sajad Enteshari 
  Abstract: This study optimises water release from the Zayandehrud Dam to better meet agricultural and environmental needs under existing annual allocation and hydraulic constraints. Due to severe water scarcity and socio-legal limitations, the focus was on improving the timing not the volume of water distribution. Two indices were developed: the agricultural demand-supply adaptation index (ADSAI) and the environmental demand-supply adaptation index (EDSAI). Results showed that current releases poorly align with irrigation and ecological demands. However, the optimised scenario significantly improved both indices. For example, ADSAI values for Mahyar, Nekoabad-Borkhar, Abshar, and Rudashtein canals increased from 2.3%, 23.6%, 50.3%, and 34% to 47.26%, 77.7%, 82.5%, and 79.33%, respectively. EDSAI rose from 27.7% to 57.27%. These findings highlight that even without structural changes, optimising release timing can enhance water use efficiency and ecological outcomes in constrained water systems, offering practical guidance for resource management.
  Keywords: water release optimisation; demand-supply adaptation index; Zayandehrud basin; water resources management; agricultural irrigation; environmental water requirements.
  DOI: 10.1504/IJHST.2026.10078889
   
  
• Unravelling the effects of hydrological events on the physicochemical and rheological properties of urban sediments in the Saida Basin in northwest Algeria  
  by Hadj Aimer, Abdelkrim Hazzab, Belaid Fatmi, Asma Rahmani, Laouni Gaidi, Khaled Korichi 
  Abstract: This research analyses the impact of hydrological forcing (rainfall intensity and seasonal droughts) on the physicochemical and rheological properties of urban sediments in the semi-arid Saida Basin (northwestern Algeria). A multidisciplinary approach combines systematic sampling during contrasting events with particle size analyses (sieving/sedimentometry), organic matter (calcination), Atterberg limits, heavy metals (atomic absorption spectrometry) and the rheological properties modelled by the Herschel-Bulkley equation (rotary rheometer). The results reveal a high temporal variability of sediment inputs, closely linked to the energy of rain events fractions 63-250 um and associated pollutants are the most present in the solid input. On the other hand, dry periods increase the organic matter content. This directly regulates the plasticity, cohesion and non-Newtonian rheological behaviour of the sediments. These dynamics substantiate the primacy of hydrological forcing and support the need for adaptive sediment management techniques, including nature-based solutions, to mitigate hydro-sedimentary hazards in arid urban areas.
  Keywords: urban sediments; hydrological forcing; sediment transport; physicochemical properties; sediment rheology; organic matter; hydro-sedimentary risk; adaptive sediment management; semi-arid basin Algeria.
  DOI: 10.1504/IJHST.2026.10079048