J. Hydrol. Hydromech., Vol. 73, No. 1 - Early View, 2025, p. 1 - 10, doi: 10.2478/johh-2024-0031
Scientific Paper, English

Laura Kögler, Andreas Ruby, Thomas Iserloh, Manuel Seeger, Johannes B. Ries: Laboratory flume experiments for detection and quantification of subsurface particle transport in steep-slope vineyards

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• Coarse-grained vineyard soils like in the Moselle valley, Germany, can be highly vulnerable to soil erosion. This is due to the non-sustainable soil management using heavy machinery and eliminating the vegetation cover on steep slopes. Through the particular combination of compacted subsoil and topsoil loosened by tillage, the vineyard experiences subsurface runoff after rainfall events. There is a knowledge gap concerning the identification and quantification of transported soil particles in the aforementioned subsurface runoff, as these processes are difficult to accurately measure under field conditions compared to surface runoff. In this paper, an experimental laboratory setup is presented including a newly developed sediment trap to measure and quantify the transport of fine soil particles in subsurface flow. The study showed substantial differences based on the water application method. Nevertheless, the first results show a subsurface sediment discharge of 1 g l–1 on average and 6–8 g l–1 immediately after heavy soil disturbance (simulated tillage). It is highly recommended to conduct further experiments using the method that corresponds most closely to natural processes, the combined method of overflow and sprinkler, as well as installing the sediment trap in a vineyard to validate the findings. If the values can be confirmed, subsurface runoff is a significant contributor to the total soil erosion process and, compared to literature, is responsible for up to 50% of soil erosion in vineyards.
  
  KEY WORDS: Soil erosion; Subsurface flow; Subsurface runoff; Rainfall simulation; Sediment trap.
  
  Address:
  - Laura Kögler, Justus-Liebig-University Giessen, Department of Physical Geography, 35390 Giessen, Germany. Trier University, Department of Physical Geography, 54296 Trier, Germany. (Corresponding author. Tel.:+49 641 99-36252 Fax.: Email: Laura.Koegler@geogr.uni-giessen.de)
  - Andreas Ruby, Trier University, Department of Physical Geography, 54296 Trier, Germany. Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Geomorphology, 14473 Potsdam, Germany.
  - Thomas Iserloh, Trier University, Department of Physical Geography, 54296 Trier, Germany.
  - Manuel Seeger, Trier University, Department of Physical Geography, 54296 Trier, Germany.
  - Johannes B. Ries, Trier University, Department of Physical Geography, 54296 Trier, Germany.

J. Hydrol. Hydromech., Vol. 73, No. 1 - Early View, 2025, p. 1 - 13, doi: 10.2478/johh-2024-0032
Scientific Paper, English

Mujahid Iqbal, Usman Ghani: Investigating the discharge characteristics over a piano key weir with varying key slope and key width ratios under varying discharges

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• The objective of the present study was to investigate the effect of inlet to outlet key slope ratios (Si/So), inlet to outlet key width ratios (Wi/Wo) and head over the weir on the coefficient of discharge (Cpkw) of type-A trapezoidal piano key weir (TPKW). It was observed that the Cpkw of TPKW was found to be decreased as the Si/So ratio reduced. The percentage of reduction in Cpkw was found to be 18.5%, 16%, 13.7%, 9.4%, 6.3%, and 3% at Si/So = 0.60, 0.75, 0.80, 1.00, 1.25, and 1.33, respectively in comparison with the Si/So = 1.67. As far as the effect of Wi/Wo ratio on the Cpkw of TPKW is concerned, the Cpkw of TPKW was observed to be increased with increasing Wi/Wo ratios. Moreover, the Cpkw at Wi/Wo = 1.32 and Wi/Wo = 1.15 was found to be 9.4% and 7.5% higher than Wi/Wo=1 respectively, while for the case of Wi/Wo = 0.76, its value was found to be 3.3% lower than Wi/Wo = 1. Furthermore, the hydraulic efficiency of TPKW was found to be decreased as head over the weir increased. The maximum value of Cpkw of TPKW was observed to be 3.2 corresponding to lowest h/P ratio for the model having Si/So = 1.67 and Wi/Wo = 1.32, while the minimum value of Cpkw of TPKW was found to be 1.58 corresponding to highest h/P ratio for the model having Si/So = 0.60 and Wi/Wo = 0.76. Additionally, sensitivity analysis results revealed that the Cpkw of TPKW is more sensitive with h/P ratio than other ratios.
  
  KEY WORDS: Coefficient of discharge; Inlet to outlet key slope ratios; Inlet to outlet key width ratios; Trapezoidal piano key weir; Type-A piano key weir.
  
  Address:
  - Mujahid Iqbal, Department of Civil Engineering, University of Engineering and Technology, Taxila, Pakistan.
  - Usman Ghani, Department of Civil Engineering, University of Engineering and Technology, Taxila, Pakistan. (Corresponding author. Tel.: Fax.: Email: usman.ghani@uettaxila.edu.pk)