J. Hydrol. Hydromech., Vol. 74, No. 2, 2026, p. 74 - 83, doi: https://doi.org/10.2478/johh-2026-0006
Scientific Paper, English

Pavla Pekárová, Zbyněk Bajtek, Ján Pekár, Pavol Miklánek, Igor Leščešen, Tomáš Borároš: From decadal runoff depletion to daily streamflow cycles: The role of riparian evapotranspiration in a forested catchment

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• This study investigates the role of evapotranspiration in the hydrological balance of the small forested Vydrica catchment (Slovakia) by linking long-term climatic trends with short-term streamflow dynamics. A 60-year mass balance analysis (1961–2020) was integrated with high-frequency streamflow observations across nine severe summer drought events (1992–2025). The long-term analysis revealed a paradoxical trend: despite a slight increase in precipitation, annual runoff significantly decreased. This decline is driven by rising air temperatures and increased evaporative demand, causing altered seasonal runoff distribution and more severe summer low flows. The short-term event analysis demonstrated that diurnal streamflow fluctuations are strongly controlled by available baseflow. During moderate droughts, active riparian vegetation generates distinct diurnal streamflow cycles with a typical six-hour lag behind maximum air temperature. However, during extreme low-flow periods, the diurnal amplitude flattens and evapotranspiration losses drop by an order of magnitude, indicating that the groundwater table has fallen below the effective root zone. The findings prove that climate-driven long-term warming continuously depletes baseflow reserves, progressively restricting the daily transpiration capacity and resilience of riparian forests.
  
  KEY WORDS: Evapotranspiration; Hydrological balance; Small forested catchment; Diurnal streamflow fluctuations; Low flows.
  
  Address:
  - Pavla Pekárová, Institute of Hydrology SAS, Dúbravská cesta 9, 841 04 Bratislava, Slovak Republic. (Corresponding author. Tel.: Fax.: Email: pekarova@uh.savba.sk)
  - Zbyněk Bajtek, Institute of Hydrology SAS, Dúbravská cesta 9, 841 04 Bratislava, Slovak Republic.
  - Ján Pekár, Comenius University in Bratislava, Faculty of Mathematics, Physics, and Informatics, Mlynská dolina, 842 48 Bratislava, Slovak Republic.
  - Pavol Miklánek, Institute of Hydrology SAS, Dúbravská cesta 9, 841 04 Bratislava, Slovak Republic.
  - Igor Leščešen, Institute of Hydrology SAS, Dúbravská cesta 9, 841 04 Bratislava, Slovak Republic.
  - Tomáš Borároš, Slovak Hydrometeorological Institute, Jeséniova 17, P. O. BOX 15, 833 15 Bratislava 37, Slovak Republic.

J. Hydrol. Hydromech., Vol. 74, No. 2, 2026, p. 84 - 97, doi: https://doi.org/10.2478/johh-2026-0007
Scientific Paper, English

Jaromír Říha, Stanislav Kotaška: Backward analysis of the Bílá Desná dam break outflow

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• In September 1916, the Austro-Hungarian Empire (today the Czech Republic) experienced the failure of the embankment dam Bílá Desná (historically named Weiße Desse), which at that time was the most disastrous dam failure in central Europe. In this study, available information on the failure of the Bílá Desná dam was gathered and analysed. The initiating cause of the Bílá Desná dam failure was an internal erosion. For the backward analysis of the dam failure, the method of analogy, empirical formulae, and three numerical models, AREBA, DL Breach and HEC-RAS were used. Due to uncertainty in the reservoir volume, the solution was carried out for the originally determined (during the dam design) and newly determined reservoir volumes. The analysis indicates the peak breach outflow range between about 360 and 810 m3/s. The most realistic and probable peak outflow discharge is about 520 m3/s. The comparison of individual methods indicate that the AREBA numerical model using Opendata (2024) provides the most realistic failure hydrograph.
  
  KEY WORDS: Bílá Desná; Dam; Breach; Internal erosion; Backward analysis.
  
  Address:
  - Jaromír Říha, Brno University of Technology, Faculty of Civil Engineering, Institute of Water Structures, Veveří 331/95, 602 00 Brno, Czech Republic. (Corresponding author. Tel.: Fax.: Email: riha.j@vutbr.cz)
  - Stanislav Kotaška, Brno University of Technology, Faculty of Civil Engineering, Institute of Water Structures, Veveří 331/95, 602 00 Brno, Czech Republic.

J. Hydrol. Hydromech., Vol. 74, No. 2, 2026, p. 98 - 112, doi: https://doi.org/10.2478/johh-2026-0008
Scientific Paper, English

Gaetano Caltabellotta, Dario Autovino, Massimo Iovino, Vincenzo Bagarello: A four-year monitoring of beerkan infiltration rates in a sandy-loam soil

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• Long-term investigations on temporal variability of infiltration rates are important for characterizing the porous medium but they are challenging and infrequent. Infiltration rates were measured in a sandy-loam soil by performing 16 beerkan infiltration runs on 14 sampling dates during a nearly four-year period. The means of the initial infiltration rates (i0) varying by approximately four times, were less variable than the means of both the final (if) and the mean (imed) infiltration rates, varying by 13 and nine times, respectively. The means of all considered parameters decreased as the antecedent soil water content (i) increased but the i effect was stronger for i0 (coefficient of determination, R2 = 0.84) than both if and imed (R2 = 0.55-0.68). With reference to these last two parameters, i effects were significant for the lowest measured values (R2 = 0.63-0.76) but not for the highest ones (R2 = 0.12-0.13). Particularly small if and imed values were obtained in initially very wet soil conditions. The antecedent soil water content can be expected to strongly control infiltration rates in a sandy-loam soil. Sampling the widest possible range of i values is recommended to obtain the most complete information about temporal variability of infiltration rates.
  
  KEY WORDS: Single-ring infiltration; Soil hydrodynamic behaviour; Time variations; Early- and late-time infiltration rates; Soil water content effects.
  
  Address:
  - Gaetano Caltabellotta, Department of Agricultural, Food and Forest Sciences, University of Palermo, Viale delle Scienze, 90128 Palermo, Italy.
  - Dario Autovino, Department of Agricultural, Food and Forest Sciences, University of Palermo, Viale delle Scienze, 90128 Palermo, Italy. (Corresponding author. Tel.: Fax.: Email: dario.autovino@unipa.it)
  - Massimo Iovino, Department of Agricultural, Food and Forest Sciences, University of Palermo, Viale delle Scienze, 90128 Palermo, Italy.
  - Vincenzo Bagarello, Department of Agricultural, Food and Forest Sciences, University of Palermo, Viale delle Scienze, 90128 Palermo, Italy.

J. Hydrol. Hydromech., Vol. 74, No. 2, 2026, p. 113 - 124, doi: https://doi.org/10.2478/johh-2026-0009
Scientific Paper, English

Mustafa Çakir, Gizem Nazli Ural, Mükerrem Oral, Okan Oral, Mesut Yilmaz: Explainable AI and Ensemble Machine Learning Analysis of River Flow Dynamics: Influence of Key Climatic Variables (Temperature, Humidity, Precipitation)

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• Accurate short-term river flowrate forecasting is essential for flood risk mitigation and sustainable water management. However, many machine learning (ML) applications in hydrology lack strict temporal validation and interpretability, limiting operational reliability. This study develops a reproducible and explainable framework for one-day-ahead daily flowrate forecasting in the Eşen River Basin (Türkiye) using hydro-meteorological data (2017-2022) from one flowrate station and four meteorological monitoring stations.The workflow integrates the Box-Cox transformation, lag-based feature engineering (up to 3 days, reflecting short-term hydrological memory), Boruta feature selection, and strictly time-aware rolling validation (2017-2021 training; 2022 independent test). Classical time-series models (ARIMA, TBATS), interpretable baselines (DT, LR), and advanced ML algorithms (RF, GBM, XGBoost, SVM, ANN) were benchmarked using RMSE, MAE, R², NSE, and KGE. Ensemble tree-based models consistently outperformed classical and baseline approaches in magnitude-sensitive metrics. XGBoost achieved the highest predictive accuracy (R² = 0.864; NSE = 0.864; RMSE = 6590 dm³ s⁻¹). Although TBATS yielded the highest KGE (0.865), ensemble models better captured nonlinear dynamics and flowrate variability. SHAP and LIME analyses revealed that short-term flow lags dominate predictive structure, while precipitation and temperature exert regime-dependent influence. The complete workflow is openly deployed via a reproducible R-Shiny environment. The results demonstrate that explainable ensemble learning, combined with strict temporal validation, provides a reliable and transparent framework for operational hydrological forecasting.
  
  KEY WORDS: Daily flowrate forecasting; Ensemble learning; Explainable AI; SHAP; LIME; Time-aware validation; Hydrology.
  
  Address:
  - Mustafa Çakir, Iskenderun Vocational School of Higher Education, Iskenderun Technical University, Iskenderun, Türkiye.
  - Gizem Nazli Ural, Faculty of Fisheries, Akdeniz University, Antalya, Türkiye.
  - Mükerrem Oral, Kemer Faculty of Maritime, Akdeniz University, Antalya, Türkiye.
  - Okan Oral, Faculty of Engineering, Akdeniz University, Antalya, Türkiye.
  - Mesut Yilmaz, Faculty of Fisheries, Akdeniz University, Antalya, Türkiye. (Corresponding author. Tel.: Fax.: Email: myilmaz@akdeniz.edu.tr)

J. Hydrol. Hydromech., Vol. 74, No. 2, 2026, p. 125 - 136, doi: https://doi.org/10.2478/johh-2026-0010
Scientific Paper, English

D.A.L. Leelamanie, Morihiro Maeda: Time-dependent contact angle and repellency persistence in water-repellent Japanese forest soils in relation to droplet geometry and line tension

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• Water repellency (WR) restricts the spontaneous wetting of soil and lowers the affinity between soil and water. Studies focused on temporal alteration of droplet contact angles on hydrophobic soil substrates and their relation to persistence of WR are highly limited. This study examined time-dependent contact angle and WR persistence considering geometry and line tension droplets using six hydrophobic forest soils. Soils were collected from Japanese cedar (Cryptomeria japonica, CED1, CED2), Japanese cypress (Chamaecyparis obtusa, CYP1, CYP2), and cedar/cypress mixed (MIX1, MIX2) forests. The time-dependence of apparent and geometric soil-water contact angles (θA and θG, respectively) and repellency persistence, using the water drop penetration time (WDPT), were determined. In all tested soils, both θA and θG showed a gradual continuous decline with increasing time to reach zero within a period of ~5–6 min, with strong negative exponential correlations (R2 ≥ 0.90). The θA showed a strong positive linear correlation with θG (R2 > 0.99; p < 0.05), indicating the preservation of a fair spherical segment shape of droplets during spreading irrespective of the possible roughness on granular soil surfaces. The line tensions at the periphery of the contact circle of the water droplet on the tested hydrophobic soil surfaces were in a range of 200–300 μJ m–1, which was within the previously reported order-of-magnitude range (10–5–102 μJ m–1). The time-dependent nature of the contact angle in the present study can most likely be attributed to water molecule adsorption processes or amphiphilic molecular reorientation processes. The soil-water contact time until contact angle receded below 90° (CT-θ90°) was not equivalent to WDPT, emphasizing that the time-dependent decline of contact angle would not correspond with water infiltration into the soil matrix. Still, the strong positive linear correlation between CT-θ90° and WDPT (R2 = 0.926; p < 0.05) indicated a close relation between these two parameters.
  
  KEY WORDS: Droplet geometry; Line tension; Repellency persistence; Soil water repellency; Time-dependence of contact angle.
  
  Address:
  - D.A.L. Leelamanie, Department of Soil Science, Faculty of Agriculture, University of Ruhuna, Mapalana, Kamburupitiya 81100, Sri Lanka. Graduate School of Environmental and Life Science, Okayama University, 3-1-1 Tsushima-Naka, Kita-Ku, Okayama 700-8530, Japan. (Corresponding author. Tel.: Fax.: Email: leelamanie@soil.ruh.ac.lk)
  - Morihiro Maeda, Graduate School of Environmental and Life Science, Okayama University, 3-1-1 Tsushima-Naka, Kita-Ku, Okayama 700-8530, Japan.

J. Hydrol. Hydromech., Vol. 74, No. 2, 2026, p. 137 - 148, doi: https://doi.org/10.2478/johh-2026-0011
Scientific Paper, English

Alirahm Rahimpour, Hossein Afzalimehr, Saeid Okhravi, Mohammad Nazari-Sharabian, Moses Karakouzian: Flow structure in a local meander bend of a gravel-bed river

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• This study investigates the spatial variability of flow structure in a natural meandering bend of the Kheir-Abad River, a gravel-bed mountain stream in southwestern Iran, with emphasis on velocity distribution, boundary shear stress, and secondary circulation. Field measurements were conducted along a 270 m reach (arc angle 113°) across nineteen cross-sections, revealing a highly heterogeneous flow field characterized by a central high-velocity core and reduced velocities near the banks. Comparison with HEC-RAS simulations shows that the model captures the general spatial organization of velocity and shear stress, but produces a smoothed representation and underestimates localized variations, particularly in downstream sections where field data indicate pronounced acceleration and peak shear stress values (up to 84.1 Pa). The observed shear stress distribution deviates from classical outer-bank dominance, with maximum values frequently occurring in the central channel and downstream regions, reflecting the influence of coarse bed roughness, complex secondary flow structures, and thalweg-controlled momentum concentration. Analysis of the secondary flow coefficient (C) supports this interpretation, with peak values coinciding with zones of increased velocity and shear stress, indicating intensified momentum exchange and enhanced near-bed transport capacity. Overall, the results demonstrate that flow in gravel-bed meanders is governed by strongly non-uniform and three-dimensional processes that cannot be fully captured by simplified hydraulic assumptions, and that integrating field measurements with numerical modeling provides a robust framework for interpreting flow dynamics and their morphodynamic implications.
  
  KEY WORDS: Flow Structure; Meander bend; Gravel-bed river; Shear stress; Secondary flow.
  
  Address:
  - Alirahm Rahimpour, Faculty of Civil Engineering, Iran University of Science and Technology, Tehran 16846-13114, Iran.
  - Hossein Afzalimehr, Faculty of Civil Engineering, Iran University of Science and Technology, Tehran 16846-13114, Iran. (Corresponding author. Tel.: Fax.: Email: hafzali@iust.ac.ir)
  - Saeid Okhravi, Institute of Hydrology, Slovak Academy of Sciences, Dúbravská cesta 9, Bratislava, 84104, Slovakia. (Corresponding author. Tel.: Fax.: Email: saeid.okhravi@savba.sk)
  - Mohammad Nazari-Sharabian, Department of Engineering, Central Connecticut State University, New Britain, CT 06050, USA.
  - Moses Karakouzian, Department of Civil and Environmental Engineering and Construction, University of Nevada, Las Vegas, NV 89154, USA.

J. Hydrol. Hydromech., Vol. 74, No. 2, 2026, p. 149 - 160, doi: 2026_74_2_Leemaniea_125
Scientific Paper, English

Dimos Touloumidis, Efstathios K. Oikonomou: Rethinking Design Rainfall Estimation under Non-Stationary Extremes and Imperfect Reanalysis Data

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• Design rainfall return levels are critical inputs for engineering applications such as urban drainage design, flood mitigation, resilient transport infrastructure and climate-sensitive planning. However, their estimation is significanlty challenged by changing rainfall regimes, which can weaken the stationarity assumptions traditionally used in design rainfall analysis. A second challenge is data availability: design estimates rely on long gauge records that are often spatially sparse, while reanalysis products such as ERA5-Land provide spatial continuity but may poorly represent point-scale extremes, especially in convectively active and topographically complex settings. This study develops a reproducible GEE workflow to jointly examine these challenges by assessing temporal changes in extreme precipitation return levels and evaluating the reliability of ERA5-Land for design-oriented rainfall screening. Annual maxima from ERA5-Land daily precipitation are modelled using Gumbel and GEV distributions, with the workflow demonstrated globally and evaluated locally in Thessaloniki, Greece, against a long in-situ gauge record for return periods of 5, 10, 50 and 100 years. Results show that ERA5-Land systematically underestimates gauge-based design rainfall, with discrepancies increasing toward rarer events; consequently, gauge-to-ERA5-Land correction factors range from 1.17 to 1.29 under Gumbel and from 1.13 to 1.46 under GEV. A reference-to-recent period comparison further indicates substantial gauge-inferred intensification, including an approximately 33% increase in the 100-year Gumbel return level, while ERA5-Land shows little corresponding change. The proposed framework is reproducible and transferable for screening applications, but correction factors remain site-specific and require local gauge validation before engineering use.
  
  KEY WORDS: Extreme precipitation; Design rainfall; Extreme value theory; Correction factors.
  
  Address:
  - Dimos Touloumidis, Information Systems and e-Business Laboratory, Department of Applied Informatics, School of Information Sciences, University of Macedonia, 546 36 Thessaloniki, Greece. Centre for Research and Technology Hellas, Hellenic Institute of Transport, 57001 Thermi, Greece. (Corresponding author. Tel.: Fax.: Email: touldimos@uom.edu.gr)
  - Efstathios K. Oikonomou, School of Rural and Surveying Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.

J. Hydrol. Hydromech., Vol. 74, No. 2, 2026, p. 161 - 176, doi: https://doi.org/10.2478/johh-2026-0013
Scientific Paper, English

Shihao Dong, Jun Wang, Tong Wang, Jueyi Sui: The effects of ice-water discharge ratio and flow Froude number on local scour around ta.ndem double piers and ice jam thickness in an S-shaped channel

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• In cold regions, bridge piers in rivers can alter flow characteristics and influence the formation and evolution of ice jams, complicating the local scour around the piers and the distribution of ice jam thickness. This study, based on experiments conducted in an S-shaped flume, examines how the flow Froude number and the ice-water discharge ratio affect the local scour depth around tandem double piers and the ice jam thickness. The results reveal that, while a positive correlation exists between the flow Froude number and the scour depth under both open flow and ice-covered flow conditions, the relationship between the scour depth and the flow Froude number under ice-jammed flow conditions is considerably more complex. Due to the influence of the ice jam on scour depth, there exists a critical Froude number at which the relationship between the flow Froude number and scour depth changes. The results indicate that when the flow Froude number is below the critical value, the ice jam thickness decreases slightly, while the scour depth shows a positive correlation with the flow Froude number. When the flow Froude number reaches the critical Froude number, the scour depth peaks. When the flow Froude number exceeds the critical value, the ice jam thickness decreases significantly, and the scour depth becomes negatively correlated with the flow Froude number. Additionally, when the flow Froude number remains constant, an increase in the ice-water discharge ratio leads to a rise in ice jam thickness, which in turn causes the scour depth to increase.
  
  KEY WORDS: Ice jam; S-shaped channel; Tandem double piers; Ice-water discharge ratio; Local scour.
  
  Address:
  - Shihao Dong, School of Civil and Hydraulic Engineering, Hefei University of Technology, 193 Tunxi Road, Hefei, Anhui, China.
  - Jun Wang, School of Civil and Hydraulic Engineering, Hefei University of Technology, 193 Tunxi Road, Hefei, Anhui, China. (Corresponding author. Tel.: Fax.: Email: junwanghfut@126.com)
  - Tong Wang, The Research Center of Water Resources and Hydropower Engineering Technology, Bengbu, Anhui, China.
  - Jueyi Sui, School of Engineering, University of Northern British Columbia, 3333 University Way, Prince George, BC, Canada.

J. Hydrol. Hydromech., Vol. 74, No. 2, 2026, p. 177 - 211, doi: https://doi.org/10.2478/johh-2026-0014
Scientific Paper, English

Birol Kaya, Maryam Adhami, Ceren Ustabaş, Amin Gharehbaghi, Ehsan Afaridegan: Monthly and fixed coefficient calibration of empirical reference evapotranspiration equations: A case study for a Mediterranean climate (Izmir Province)

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• Accurate estimation of reference evapotranspiration (ET₀) is essential for efficient irrigation and water resource management, particularly in water-scarce regions. Although the FAO56 Penman–Monteith (PM-FAO56) equation is widely accepted as the standard method, its application is often constrained by the requirement for comprehensive meteorological data. This study provides a regional evaluation and calibration of three widely used empirical ET₀ models Hargreaves and Samani (temperature-based), Priestley and Taylor (radiation-based), and Mahringer (mass transfer-based) under Mediterranean climatic conditions in İzmir, Türkiye. Daily meteorological data from 40 stations covering the period 2000–2020 were used. Model performance was assessed against PM-FAO56 using the coefficient of determination (R²), mean absolute error (MAE), root mean square error (RMSE), percentage error (PE), Nash–Sutcliffe efficiency (NSE) and mean bias error (MBE). Calibration was performed using least squares (LS) regression and a gradient-based optimization approach, with both fixed and monthly varying coefficients. Before calibration, the Priestley–Taylor model showed the best performance among the empirical equations (R² = 0.932, MAE = 0.68, RMSE = 0.92, PE = 7.32, NSE=0.796, MBE=-0.65). After calibration, all models improved substantially, with the Mahringer equation achieving the highest accuracy when monthly coefficients were applied (R² = 0.995, MAE = 0.05, RMSE = 0.154, PE = 1.41, NSE=0.992, MBE=0.022). The LS and gradient-based optimization approaches produced nearly identical results. In addition, the reconstruction of missing sunshine duration (ADS) data using a regression-based approach enabled the inclusion of a more spatially representative dataset without introducing significant bias into the calibration results. The findings demonstrate that locally calibrated empirical equations, particularly when temporal variability is accounted for through monthly coefficients, can provide highly accurate ET₀ estimates with relatively limited data requirements. This study provides practical monthly and fixed calibration coefficients for the İzmir region and supports the use of monthly calibrated empirical models for irrigation planning in Mediterranean environments.
  
  KEY WORDS: Reference evapotranspiration; Calibration; Water management; Mediterranean climate.
  
  Address:
  - Birol Kaya, Department of Civil Engineering, Faculty of Engineering, Dokuz Eylül University, Izmir, Türkiye. (Corresponding author. Tel.: Fax.: Email: birol.kaya@deu.edu.tr)
  - Maryam Adhami, Department of Watershed Management Engineering, Faculty of Natural Resources, Tarbiat Modares University, Noor, Mazandaran, Iran.
  - Ceren Ustabaş, Department of Civil Engineering, Faculty of Engineering, Dokuz Eylül University, Izmir, Türkiye.
  - Amin Gharehbaghi, Department of Civil Engineering, Faculty of Engineering, Hasan Kalyoncu University, Gaziantep, Türkiye.
  - Ehsan Afaridegan, Department of Civil Engineering, Faculty of Engineering, Yazd University, Yazd, Iran.

J. Hydrol. Hydromech., Vol. 74, No. 2, 2026, p. 212 - 223, doi: https://doi.org/10.2478/johh-2026-0015
Scientific Paper, English

Zeroual Abdelatif, Fourar Ali: Geometric shift–aware uncertainty quantification for discharge coefficient prediction of triangular planform weirs

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• Reliable estimation of the discharge coefficient Cd is central to sharp-crested weir hydraulics, yet data-driven models are commonly evaluated with random train-test splits that can overstate generalization when experiments are structured by discrete geometries. Using a reconstructed run-level dataset for triangular planform weirs (n=123) spanning vertex angles θ ∈{30o,60 o,90 o,120 o,150 o,180 o }, this study benchmarks tabular regression under (i) random 80/20 splitting, which represents interpolation within a mixed-geometry dataset, and (ii) a leave-one-angle-out (LOAO) protocol that enforces geometric domain shift. Dimensionless predictors are derived from Buckingham-π reasoning and formulated to remain numerically stable as θ →180°. Under random splitting, gradient boosting achieves high accuracy, whereas LOAO reveals substantially weaker generalization, with the largest errors near the θ = 180° regime transition. For uncertainty quantification, global split conformal intervals are near-nominal under random splits but severely under-cover under LOAO, indicating that calibration residuals are not transferable across geometries. CV-pooled residual calibration restores LOAO coverage at the cost of substantially wider intervals. Finally, combining k-nearest-neighbor distance-based out-of-distribution detection with a two-tier interval policy yields intermediate operating points that better balance reliability and sharpness when deploying beyond the calibration envelope. Overall, the results indicate that apparently strong interpolation performance can conceal important geometric extrapolation failures, and that safe deployment on novel weir geometries requires explicitly shift-aware uncertainty quantification.
  
  KEY WORDS: Triangular planform weir; Discharge coefficient; Domain shift; Conformal prediction; Out-of-distribution detection; Selective prediction.
  
  Address:
  - Zeroual Abdelatif, Department of Hydraulic, Faculty of Sciences and Applied Sciences, University of Oum El Bouaghi, Algeria. Sustainable Development and Environmental Protection Laboratory (SDEPL), University of Oum El Bouaghi, Algeria. (Corresponding author. Tel.: Fax.: Email: abdelatif.zeroual@univ-oeb.dz)
  - Fourar Ali, Laboratory of Applied Research in Hydraulics, Department of Hydraulic, Faculty of Technology, University of Batna 2, Batna, Algeria.