International Journal of Hydrology Science and Technology (14 papers in press)

Regular Issues

• Spatial pattern of volcanic spring in the Holocene stratovolcano and volcanic complex under the diversity of geomorphological aspects: a study from Central Java, Indonesia  
  by Suhadi Purwantara, Arif Ashari, Nurul Khotimah, Sutanto Tri Juni Putro 
  Abstract: This paper analyses the distribution pattern of springs and evaluates the influence of the diversity of geomorphological aspects on the distribution pattern of springs. This study collected data through observation, remote sensing, literature study, and documents. A survey was carried out using a systematic sampling method. Data were analysed by geographic information system analysis using the average nearest neighbour, supported by statistical analysis of comparative tests. There are several significant findings in this study. First, the distribution of springs in the stratovolcano has a clustered pattern. Second, the distribution in the volcanic complex is random. Third, the formation of radial valleys due to denudation triggers the emergence of springs. Last, the average discharge and water quality are relatively the same. In summary, this study provides new insights into the distribution pattern of springs in stratovolcano and volcanic complexes in wet tropical climates, which is still very limited in the previous literature.
  Keywords: spring; stratovolcano; volcanic complex; Central Java; Indonesia.
  DOI: 10.1504/IJHST.2025.10072939
   
  
• Challenges of implementing integrated water resources management: a review of climate-driven land cover changes and water security issues in the Caribbean Community and Jordan  
  by Ramgopaul Roop, Mohammed Matouq, Abhishek Tiwary, Ana Paula Fonseca, Miles Weaver 
  Abstract: Climate change has intensified hydrometeorological hazards droughts, floods, storms, and heat stress threatening water quality, availability, and land sustainability. This study explores barriers to implementing integrated water resources management (IWRM) in response to climate impacts on land and water systems. It reviews global trends in climate driven land cover change and water insecurity, then compares the experiences of two contrasting regions: the Small Island Developing States of the Caribbean Community (CARICOM) and Jordan. Despite distinct geographies, both face escalating vulnerabilities from limited arable land, population pressures, and developmental needs. Using decade-long longitudinal data, the study analyses national adaptation policies, particularly in agriculture and water management. Findings show both regions have tailored policies but lack adequate financial resources to implement them effectively. The study underscores the urgent need for international support, technological innovation, and policy guidance to strengthen resilience and sustainable development in water-scarce regions under climate stress.
  Keywords: CARICOM; climate change; integrated water resource management; land use; small island developing states; SIDS; Jordan.
  DOI: 10.1504/IJHST.2025.10073369
   
  
• Sensitivity analysis of different aridity indices in the Iraq region  
  by Omar M.A. Mahmood Agha 
  Abstract: This study seeks to explore the sensitivity of different aridity indices of Iraq to climatic variables such as precipitation, temperature, and evapotranspiration. Different aridity indices such as Lang, De Martonne, Erinc, UNESCO, and UNEP indices were applied in the assessment of dryness in various regions of Iraq. Sensitivity analysis was done to assess the impact of a variation in climatic factors like rainfall, temperature, and evapotranspiration on the aridity indices. Sensitivity from the standard deviations of the variables was applied to ascertain its impact on the aridity index. The analysis revealed that rainfall had the highest impact with sensitivity coefficients ranging from 0.31 to 0.66. The temperature sensitivity ranged between the relatively low values of 0.02 to 0.07. The study concluded that the UNEP index was best to represent aridity in Iraq because it is more sensitive to climatic variables, especially evapotranspiration.
  Keywords: sensitivity; aridity; Iraq; precipitation; temperature; evapotranspiration; UNEP; Lang; De Martonne; UNESCO.
  DOI: 10.1504/IJHST.2025.10073386
   
  
• Investigating the use of drip irrigation systems under different water and soil conditions  
  by Yaser Sabzevari, Saeid Eslamain 
  Abstract: One of the techniques for optimal use of water resources is the use of modern irrigation methods with proper design and implementation. The evaluation of irrigation systems determines their strengths and weaknesses. The purpose of this research is to evaluate drip irrigation systems in Iran. For this purpose, four drip irrigation systems were evaluated under different soil and water quality conditions based on the parameters of uniformity of water distribution, irrigation efficiency and uniformity of pressure distribution in the pipes. The results showed that the basic problems in drip irrigation systems were: the inappropriate number and type of drippers, the amount of pressure and its non-uniform distribution, low wetted surface, inappropriate depth of irrigation water and the low level of skill and knowledge of users.
  Keywords: drip irrigation; efficiency; uniformity of water distribution.
  DOI: 10.1504/IJHST.2025.10073570
   
  
• Error assessment in debris flow modelling with RAMMS  
  by Majid Galoie, Jihui Fan, Artemis Motamedi, Niu Ning 
  Abstract: Debris flows and landslides cause significant damage worldwide each year. To reduce these damages, it is crucial to get an accurate estimate of flow formation and its features. Because their governing equations are complex, analysing these flows is difficult, and numerical solutions are often used. The RAMMS model is one of the most popular tools for debris flow modelling, using the Voellmy-fluid friction model to simulate debris flows. This model requires relatively little input data, including the DEM map, Voellmy friction coefficients [the Dry-Coulomb friction coefficient () and the viscous-turbulent friction coefficient ()], inflow conditions, and initial flow direction. To assess how different input data affect uncertainties in RAMMS outputs, a real debris flow event with available observed data was simulated and calibrated based on its high-resolution DEM (1 m).
  Keywords: modelling uncertainty; Rapid Mass Movement Simulation; RAMMS; Debris flow modelling; DEM resolution; friction coefficients.
  DOI: 10.1504/IJHST.2025.10073650
   
  
• Technology for separation of iron in groundwater to support drinking water supply  
  by Sindu Nuranto, Agus Maryono, Pratama Tirza Surya Sembada, Fatimah Nurul Mahdiyah Jayatri, Jesica Gabriella Tapiory 
  Abstract: Groundwater is the main water source in Yogyakarta (45.92%), followed by rivers (33.71%), springs (17.85%), and reservoirs (2.52%). Most residents rely on wells for drinking water, which often contain excessive iron (Fe), posing health risks. This study aimed to develop a household-scale technology to reduce Fe concentrations in groundwater. Samples were collected from Kasihan, Bantul, and treated using an aeration method with an aerator installed in the pump pipe, producing bubbles of 300500 microns. Five aeration durations ranging from 0.5 to 11.5 hours were tested. Initial Fe levels measured 0.5 mg/L, the maximum permissible limit under Minister of Health Regulation No. 2/2023. After aeration, Fe levels decreased to 0.05 mg/L, showing a reduction of 0.45 mg/L. These findings demonstrate the effectiveness of aeration in improving water quality. The research will continue to optimise technological solutions tailored to household-scale community needs.
  Keywords: aeration; groundwater; iron; Fe; well water.
  DOI: 10.1504/IJHST.2025.10074112
   
  
• The applicability of the formulas developed on the Manning-Strickler and Keulegan equations for the calculation of flow resistance for shallow flow in gravel-bed streams - a case study  
  by Bogusław Michalec 
  Abstract: The results of field measurements in reaches with determined measuring cross-sections of four streams was used to test the applicability of conventional flow resistance equations with dimensionless variables in the form of d/D, R/D or dmax/ and R/. Among the 27 assessed formulas developed on the model of the Manning-Strickler and Keulegan equations, only the power equations of Griffiths and Charlton et al. gave satisfactory results. The applied VPE equation, developed by Ferguson, allows to obtain the estimated value of the coefficient of resistance. As a result, empirical formulas were developed as correlations of (8/f)1/2 with dimensionless parameters. Only correlation for the maximum depth (dmax) obtained higher values of the coefficient of determination. The proposed adoption of the standard deviation of the size distribution curve in dimensionless parameters in the form of dmax/ and R/, may provide a practical approach in determining the resistance coefficient.
  Keywords: resistance coefficient; roughness coefficient; sediment grain diameter; hydraulic diameter; gravel bed.
  DOI: 10.1504/IJHST.2025.10074321
   
  
• Hydrological processes of environmental isotopes in Karamana River Basin, Kerala, India: a case study of isotopic hydrology  
  by Ravi Ande, Aaron Anil Chadee, Madhuri Nigam, Darshan Mehta, Hazi Azamathulla 
  Abstract: Hydrological modelling of water resources requires a clear understanding of surface water-groundwater interactions in river basins. The Karamana River Basin, a vital source for Thiruvananthapuram city, presently lacks effective isotope-based assessments and management strategies. Environmental isotope analysis revealed that monsoon precipitation exhibited enriched δ18O values (-2.01, -2.57, -1.53%) compared to river and groundwater, indicating the significant role of rainfall in streamflow generation. Seasonal hydrochemical variations were also evident. During the non-monsoon period, cation concentrations followed Ca2+ > Na+ > Mg2+ > K+ > Fe, while anions were dominated by HCO3- > Cl- > SO42- > NO3-. In the monsoon season, the order remained similar but with reduced concentrations. Groundwater δ18O values were more depleted than those of rainfall and river water (HL = -3.12%; ML = -4.2%; LL = -2.85%), highlighting recharge contributions and seasonal variability. These findings emphasise the importance of isotope-based monitoring for sustainable basin management.
  Keywords: Karamana River Basin; hydrological modelling; stable isotope; water assessment tool; temporal variation; India.
  DOI: 10.1504/IJHST.2025.10074375
   
  
• Research on factors influencing conductivity in river water sampling contaminated by heavy metals  
  by Yan Wu, Yi Zhang, Yuanbo Wang 
  Abstract: The river water conductivity is significantly affected when contaminated by heavy metals. Experimental studies were conducted using silty clay to investigate the factors influencing water conductivity. The variations in conductivity were observed under the influence of factors such as HA content, temperature, and centrifugal filtration. Adding HA to the clay resulted in a significant increase in water conductivity. The water conductivity after centrifugal filtration was higher than before centrifugal filtration. When the concentration of CuSO4 was below 200 mg/L, the conductivity at 10 C was higher than the conductivity at 20 C. When the CuSO4 concentration was above 200 mg/L, the opposite result was observed. The correlation between the factors that significantly affected the water conductivity could be ranked as follows: CuSO4 concentration > centrifugal filtration > HA concentration. Converting unfiltered water conductivity to ion concentration results in a 10% reduction.
  Keywords: humic acid; temperature; centrifugal filtration; conductivity.
  DOI: 10.1504/IJHST.2025.10074497
   
  
• Simulation of floods using merged satellite and gauge precipitation data  
  by Obaid Khalid, Muhammad Masood, Ghulam Nabi, Hafiz Waseem Sajjad, Jahanzaib Jafar 
  Abstract: Four merging techniques: linearised weighting (LW), multiple linear regression (MLR), inverse root-mean-square error (IRMSE), weighting and optimal interpolation (OI) were applied to merge widely used satellite precipitation datasets (SPDs). Statistical evaluation was done using: root mean square error (RMSE), Pearson correlation coefficient (r) and bias. While Nash-Sutcliffe efficiency (NSE), coefficient of determination (R²) and percent bias (PBIAS) were used to assess the SWAT model performance. Peak events were evaluated using peak rate discharge errors (E_NS and E_RP). The statistical evaluations proved OI, the most suitable data merging technique. Hydrological assessment showed that the observed and simulated flows have a strong correlation for both the gauge and the merged data. For peak evaluation, the values of E_NS and E_RP were close to their optimal values of 1 and 20, respectively. Peak rate discharge error (E_RP) has lesser values for the merged data as compared to the gauge data, advocating its use for hydrological modelling in data scares regions.
  Keywords: flood simulation; satellite precipitation data; ungauged sites; data merging methods; SWAT model; Swat River basin.
  DOI: 10.1504/IJHST.2025.10071810
   
  
• Optimisation strategy for run-of-river small hydropower plants using an e-flow approach to balance generated power and river ecological sustainability: a case study in Indonesia  
  by Andre Prasetya, Achmad Riadi, Akbar Wibawa Muhammad 
  Abstract: Achieving clean energy transitions while maintaining ecological integrity is essential for meeting sustainable development goals (SDGs). This study optimises the operation of a run-of-river small hydropower plant (SHP) in Indonesia, balancing energy production with river ecological sustainability. Using artificial neural networks (ANN) and response surface methodology (RSM), the study evaluates power generation under various environmental flow (e-flow) scenarios. Based on one year of hourly operational and hydrological data from an SHP with a 2 × 350 kW capacity, the Q_25MAF scenario was found to offer the optimal balance, increasing e-flow discharge by 89.8% while reducing power generation by only 20.54%. This scenario supports continuous operation and contributes to clean energy, climate action, and aquatic ecosystem preservation. The findings offer a practical framework for sustainable SHP operations in regions with diverse hydrological and operational conditions.
  Keywords: small hydropower plant; SHP; environmental flow; river ecological sustainability; artificial neural network; ANN; response surface methodology; RSM; optimisation; Indonesia.
  DOI: 10.1504/IJHST.2025.10071072
   
  
• Spatial and temporal variation of drought in Sichuan Province, China based on SPEI analysis  
  by Yaotian Tian, Enhao Zhang, Ke Mou, Haoran Shi, Shuang Chen, Hui Chen 
  Abstract: Drought variation is of great significance to agricultural production and social stability. Meteorological data during 19652019 in Sichuan Province was used. Drought variation was explored based on standardised precipitation evapotranspiration index (SPEI), drought frequency, and drought station ratio. The results showed that SPEI totally increased over time. Moderate drought was most severe, occurring in February-April. Mild drought was prevalent in January, November, and December. SPEI decreased from northeast to southwest. From southeast to northwest, the SPEI tendency rate increased gradually. Average drought frequency was 31.86%. Mild, moderate, severe, and extreme drought frequency was 14.89%, 10.86%, 4.34%, and 1.77%, respectively. Drought station ratio decreased over time. There were 20, 16, 9, and 2 events of local, partial regional, regional, and panregional drought, respectively. The results of this study provide a reference for drought prevention in Sichuan Province.
  Keywords: standardised precipitation evapotranspiration index; SPEI; precipitation; drought frequency; drought station ratio; drought change; China.
  DOI: 10.1504/IJHST.2025.10071552
   
  
• Investigation of BMPs to control erosion and nutrient losses using SWAT model  
  by Bidare Phalanetra Deepthi, Pushpa Tuppad, K.S. Lokesh 
  Abstract: The Upper Cauvery Basin faces water quality issues due to sediment erosion and nutrient loss from agricultural non-point source pollution, as cropland dominates the region. Identifying critical source areas (CSAs) is vital for selecting best management practices (BMPs) to mitigate this deterioration. This study used the flow-calibrated SWAT model to identify CSAs and evaluate the effectiveness of structural BMPs - contour farming, filter strips, streambank stabilisation, porous gully plugs and non-structural BMPs - no-till, cover crops, manure incorporation at hydrological response unit (HRU), subbasin, and watershed levels. Simulations showed streambank stabilisation was most effective for sediment reduction at the watershed scale (57.27%), while filter strips reduced sediment significantly at the subbasin (37.91%) and HRU (43.75%) levels and performed best for total nitrogen (TN) and total phosphorus (TP) reduction. Among non-structural BMPs, no-till reduced sediment, and manure incorporation reduced TN and TP. Structural BMPs proved more effective overall than non-structural BMPs.
  Keywords: best management practices; BMPs; structural BMP; non-structural BMP; SWAT; sediment erosion; nutrient loss.
  DOI: 10.1504/IJHST.2025.10072454
   
  
• Leveraging artificial intelligence and statistical models for predicting dam water storage: insights from a Moroccan case study  
  by Mohamed Oubraime, Abderrahim Sabour 
  Abstract: This study addresses sustainable water management challenges by proposing a forecasting approach applied to daily storage series from 45 Moroccan dams (2015-2023). Three modelling frameworks are compared: classical statistical models (autoregressive integrated moving average, ARIMA), machine learning models (support vector regression, SVR, and long short-term memory networks, LSTM), and hybrid models. Stationarity was tested using the Augmented Dickey-Fuller (ADF) test, revealing that 64% of the series are non-stationary. Trend analysis showed declining volumes in 46.7% of dams. Models were trained using five-fold cross-validation and optimised via grid search. Performance was assessed using mean absolute error (MAE) and root mean squared error (RMSE). ARIMA and SVR with linear kernel outperformed other models, suggesting mainly linear behaviour, possibly driven by anthropogenic influences. These results confirm the relevance of simple and interpretable models in semi-arid contexts, supporting strategic planning under natural and human-induced pressures.
  Keywords: water resource management; time series analysis; machine learning; hybrid models; ARIMA; long short-term memory networks; LSTM; support vector regression; SVR.
  DOI: 10.1504/IJHST.2026.10074291