Groundwater flow and transport model of the Estonian Artesian Basin and its hydrological developments

2016 ◽  
Vol 47 (4) ◽  
pp. 814-834
Author(s):  
L. Vallner ◽  
A. Porman

The sophisticated research and management problems of the Estonian water environment are considered by means of holistic modelling. The model elaborated is based on the computer code Visual MODFLOW Classic. The model encompasses the entire Estonian Artesian Basin (EAB) and the border districts of Russia and Latvia. It involves all main aquifers and aquitards on an area of 88,000 km2. The main hydrogeological and hydrological characteristics of the study area, including the time-dependent three-dimensional distribution of groundwater heads, the direction, velocity and rate of subsurface fluxes, itemised water budgets, volumes of hydrogeological units, and durations of groundwater exchange have been determined by modelling. The palaeohydrological situation during the last continental glaciation of the EAB was reconstructed and the principal problems of the sustainable management of water environment were elucidated. The model has been used to simulate the local and cumulative rates of the base flow.

2018 ◽  
Vol 471 ◽  
pp. 147-158
Author(s):  
Grzegorz SINICYN ◽  
Maria GRODZKA-ŁUKASZEWSKA

The article presents the environmental problem that occurred in the vicinity of Celsa Huta Ostrowiec, where concentrations of trichloroethene and tetrachloroethene in wells were detected. The three-dimensional numerical groundwater flow and transport models were calibrated against trichloroethene measurements. Model studies were carried out for different scenarios taking into account the type of pollution source (point and spatial distributed) and the nature of the source itself (incidental and continuous in time). The modelling results made it possible to indicate the most likely place and time of contaminant release into the soil and water environment.


Author(s):  
Tomoko Ehara ◽  
Shuji Sumida ◽  
Tetsuaki Osafune ◽  
Eiji Hase

As shown previously, Euglena cells grown in Hutner’s medium in the dark without agitation accumulate wax as well as paramylum, and contain proplastids showing no internal structure except for a single prothylakoid existing close to the envelope. When the cells are transferred to an inorganic medium containing ammonium salt and the cell suspension is aerated in the dark, the wax was oxidatively metabolized, providing carbon materials and energy 23 for some dark processes of plastid development. Under these conditions, pyrenoid-like structures (called “pro-pyrenoids”) are formed at the sites adjacent to the prolamel larbodies (PLB) localized in the peripheral region of the proplastid. The single prothylakoid becomes paired with a newly formed prothylakoid, and a part of the paired prothylakoids is extended, with foldings, in to the “propyrenoid”. In this study, we observed a concentration of RuBisCO in the “propyrenoid” of Euglena gracilis strain Z using immunoelectron microscopy.


2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Hayami Nishiwaki ◽  
Takamoto Okudaira ◽  
Kazuhiko Ishii ◽  
Muneki Mitamura

AbstractThe geometries (i.e., dip angles) of active faults from the surface to the seismogenic zone are the most important factors used to evaluate earthquake ground motion, which is crucial for seismic hazard assessments in urban areas. In Osaka, a metropolitan city in Japan, there are several active faults (e.g., the Uemachi and Ikoma faults), which are inferred from the topography, the attitude of active faults in surface trenches, the seismic reflection profile at shallow depths (less than 2 km), and the three-dimensional distribution of the Quaternary sedimentary layers. The Uemachi and Ikoma faults are N–S-striking fault systems with total lengths of 42 km and 38 km, respectively, with the former being located ~ 12 km west of the latter; however, the geometries of each of the active faults within the seismogenic zone are not clear. In this study, to examine the geometries of the Uemachi and Ikoma faults from the surface to the seismogenic zone, we analyze the development of the geological structures of sedimentary layers based on numerical simulations of a two-dimensional visco-elasto-plastic body under a horizontal compressive stress field, including preexisting high-strained weak zones (i.e., faults) and surface sedimentation processes, and evaluate the relationship between the observed geological structures of the Quaternary sediments (i.e., the Osaka Group) in the Osaka Plain and the model results. As a result, we propose geometries of the Uemachi and Ikoma faults from the surface to the seismogenic zone. When the friction coefficient of the faults is ~ 0.5, the dip angles of the Uemachi and Ikoma faults near the surface are ~ 30°–40° and the Uemachi fault has a downward convex curve at the bottom of the seismogenic zone, but does not converge to the Ikoma fault. Based on the analysis in this study, the dip angle of the Uemachi fault zone is estimated to be approximately 30°–40°, which is lower than that estimated in the previous studies. If the active fault has a low angle, the width of the fault plane is long, and thus the estimated seismic moment will be large.


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