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2. The impact of bridge pier on ice jam evolution - an experimental study
- Creator:
- Wang, Jun, Hua, Jian, Sui, Jueyi, Wu, Peng, Liu, Tao, and Chen, Pangpang
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- boundary condition, bridge pier, ice jam, and ice accumulation
- Language:
- Slovak
- Description:
- The ice jam in a river can significantly change the flow field in winter and early spring. The presence of bridge piers further complicates the hydraulic process by interacting between the ice jam and bridge piers. Using the data collected from experiments in a laboratory flume, the evolution of an ice jam around bridge piers having three different diameters has been investigated in this study. Compared to results without-pier, it was found that the formation of an ice jam in the downstream of bridge pier is faster than that in the upstream. The thickness distribution of the ice jam shows clearly different characteristics in front and behind of bridge piers at different stages of the ice jam.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3. Water table effects on measured and simulated fluxes in weighing lysimeters for differently-textured soils
- Creator:
- Wegehenkel, Martin and Gerke, Horst H.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- weighable lysimeters, modelling, Hydrus-1D, drainage, and boundary condition
- Language:
- Slovak
- Description:
- Weighing lysimeters can be used for studying the soil water balance and to analyse evapotranspiration (ET). However, not clear was the impact of the bottom boundary condition on lysimeter results and soil water movement. The objective was to analyse bottom boundary effects on the soil water balance. This analysis was carried out for lysimeters filled with fine- and coarse-textured soil monoliths by comparing simulated and measured data for lysimeters with a higher and a lower water table. The eight weighable lysimeters had a 1 m2 grass-covered surface and a depth of 1.5 m. The lysimeters contained four intact monoliths extracted from a sandy soil and four from a soil with a silty-clay texture. For two lysimeters of each soil, constant water tables were imposed at 135 cm and 210 cm depths. Evapotranspiration, change in soil water storage, and groundwater recharge were simulated for a 3-year period (1996 to 1998) using the Hydrus-1D software. Input data consisted of measured weather data and crop model-based simulated evaporation and transpiration. Snow cover and heat transport were simulated based on measured soil temperatures. Soil hydraulic parameter sets were estimated (i) from soil core data and (ii) based on texture data using ROSETTA pedotransfer approach. Simulated and measured outflow rates from the sandy soil matched for both parameter sets. For the sand lysimeters with the higher water table, only fast peak flow events observed on May 4, 1996 were not simulated adequately mainly because of differences between simulated and measured soil water storage caused by ET-induced soil water storage depletion. For the silty-clay soil, the simulations using the soil hydraulic parameters from retention data (i) were matching the lysimeter data except for the observed peak flows on May, 4, 1996, which here probably resulted from preferential flow. The higher water table at the lysimeter bottom resulted in higher drainage in comparison with the lysimeters with the lower water table. This increase was smaller for the finer-textured soil as compared to the coarser soil.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public