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Where and how much water do trees transport? Modelling the impact of spruce and beech stands on soil water fluxes during extreme climatic conditions
Zelíková, Nikol ; Šípek, Václav
Soil moisture links processes that influence the entire hydrological cycle and thus the availability of water resources. One important factor influencing these processes is the presence of vegetation. Research on the interactions between vegetation, its management and the processes affecting soil water fluxes is of particular importance in times of ongoing climate change and land cover changes. However, the complexity of these interactions, further influenced by differences between plant species, makes this research more difficult. Land cover change is also taking place in Czechia, specifically in the replacement of spruce monocultures by beech. Therefore, this study investigates the influence of two types of forest stands, spruce (Picea abies) and beech (Fagus sylvatica), on the soil water regime in the experimental Liz catchment in Bohemian Forest, Czechia. This was performed by (1) evaluating differences in soil moisture based on twenty years of measured data and (2) obtaining the two components of the soil water balance (transpiration and percolation) at two plots (beech and spruce) using a soil water balance model. Analysis of the long-term soil moisture data show slightly lower soil moisture values under the beech stands, which disappear when comparing the annual mean values. Differences are evident when evaluating average soil moisture data with depth, where the topmost layer of the soil profile at the spruce site has on average 6% higher soil water content than beech. At the start of the growing season the soil moisture was initially drier under spruce, due to its earlier start of transpiration. This difference was reduced over the season by the intensive transpiration of beech. The outputs of the balance model indicated a higher rate of actual evapotranspiration of beech and a higher rate of percolation of spruce every year. This effect was more pronounced over the dry years, whereas in years with sufficient rainfall the differences were minimal. Thus, the replacement of spruce trees by beech trees may affect the rate of groundwater recharge.
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Time variabilty of soil hydraulic properties and their impact on soil moisture estimation
Šípek, Václav ; Vlček, Lukáš ; Tesař, Miroslav ; Zelíková, Nikol ; Hnilica, Jan
The study was focused on the temporal variability of saturated hydraulic conductivity in an experimental plot covered by spruce forest and investigated benefits of its incorporation into soil water balance model. The results showed that the higher saturated hydraulic conductivity (33.6-44.8 cm hr-1) was observed in summer period compared to lower values (13.2-22.3 cm hr-1) in the winter period. The use of seasonally variabile saturated hydraulic conductivity improved the efficiency of soil water balance model in terms of lower root mean square error between observed and simulated volumetric soil water content by 33.2 %. The Nash-Sutcliffe coefficient rose from 0.34 to 0.68.
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Report on the hydroledological survey in the Černý Důl, Krkonoše Mts.
Šípek, Václav ; Vlček, Lukáš ; Zelíková, Nikol
The report documents results of hydropedological survey in the Černý Důl, Krkonoše Mts. Two experimental sites were selected based on the requirements of National Park Krkonoše with the aim to determine the effect of bark beetle outbreak on the soil water regime. The report contains description of soil hydraulic properties at two plots (healthy and impacted forest) for several soil horizons which will serve as a basis for hydropedological model.\n
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Analysis of precipitation regime in Šumava Mountains
Šípek, Václav ; Zelíková, Nikol
The analysis is focused on the description of precipitation regime in the Šumava National Park in comparison with other mountain ranges in the Czech Republic. The period of interest comprised the years 2001-2019. The daily and monthly precipitation amounts were compared to the reference period covering the years of 1971-2000.
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Potential of watercourses restoration measures as a tool for water retention in the floodplain
Zelíková, Nikol ; Matoušková, Milada (advisor) ; Jeníček, Michal (referee)
The object of this thesis is the evaluation of the restoration potential of small hydraulic structures for increasing water retention in river floodplain by using 2D HEC-RAS hydraulic model. A former millrace of the Rožnovská Bečva River was used for the design of restoration measures. The restoration proposal consists of partial modification of the current millrace and new close-to-nature watercourse in the agricultural floodplain. Restoration proposal also includes changes in land use, which consist of grassing and afforestation. The input data used for the hydraulic model are digital terrain model (5G) by ČÚZK, surface roughness parameter and mean hourly discharge data of 1997 (Q100) and 2007 (Q5) flood events provided by CHMI. The results of the hydraulic simulations point to the positive effect of proposed restoration measures especially in the change of flooded volumes (3x higher) and flooded areas (2x higher). The results indicate that restoration measures lead to the flooding from the newly designed watercourse that precedes the flooding from the Rožnovská Bečva River. This brings the possibility of more frequent occurrence of inundation events favourable for water retention in the river floodplain. Keywords: retention, floodplain, restoration, hydraulic structures, Rožnovská Bečva River,...
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