The contribution deals with hydrological as well as hydraulic evaluation of drainage system in one of the most critical region in Slovakia from hydrological, soil and geomorphological conditions. Results show the necessity of optimization of internal water drainage in Eastern Slovak Lowland. Particular attention is devoted to pumping station Pavlovce nad Uhom, which is part of the drainage system named ESL-3. Optimization lies in the evaluation of the pumping station effectiveness with regard to the flow capacity of drainage channel and pumping device parameters, which are installed to the pumping station.
In Slovakia, the year 2011 can be characterized as dry with an irregular distribution of rainfall during the whole year. However, there were also some important hydrological events in form of flash floods. One of them a flash flood on the River Gidra, which passes the village of Píla situated below the Small Carpathians. A numerical simulation of this type of flood event was the main goal of the research in order to avoid the future devastating consequences of these kinds of floods. It was necessary to setup a mathematical model of the river using the HEC-RAS modeling tool to develop a correct evaluation of the flood course and to design appropriate flood protection measures, which will enable the interception of flood waves and to protect people and their property.
The Slovak lowlands have been threatened by floods recently. The Levice district is one of the regions endangered by floods from extreme hydrological situations. The investigated river, which passes through this district is the River Podluzianka with the Cajkovsky brook and the Rybnicky brook as right-bank tributaries. The present conditions of the flood protection in the Levice district area are not sufficient. For this reason, it was necessary to analyze the river flow regime and propose appropriate flood protection measures in the mentioned region. This evaluation based on hydrological, geological and meteorological information and was performed by numerical modeling using computer code HEC-RAS. The main results of this research are presented in the paper.
Flash floods are becoming a phenomenon that troubles people more and more often in many Slovak under-mountain regions and society needs to deal with these extreme natural events. This article is showing an example of mathematical modeling of flood protection measures in Small Carpathians region. To secure flood protection, detention reservoirs have been proposed, because of their automatic function that is important due to rapid progress of flash floods. As a base for this project a previous work that attempted to reconstruct the flood has been used. HEC-RAS 4.1.0 software package was used for numerical modeling, which includes flood mitigation calculation. Six variants of proposed detention reservoirs were created and checked by a design flood wave that was created according to rainfall with recurrence period of 100 years. All of the proposed detention reservoirs have exact proportions needed to secure flood protection including height of the dam, length of the dam in crest, type and dimension of outlet and dimensions of emergency spillways. The modeling included flood wave passing during several situations - normal function of detention reservoirs, blocked outlet and dam break. This study should be considered as a base for future flood protection project. An extensive terrain survey has been performed in frame of this project.
During the flood situations in May and June 2010, the culmination of the Váh River and the Danube River was accompanied by the groundwater level rising in the Rye Island, in some boreholes even to their maximum measured levels. The increased groundwater level caused major problems, e.g. flooded cellars and underground spaces, contaminated drinking water in wells, flooded railways and farmlands. As a part of the research concentrating on the groundwater flooding phenomena in the Rye Island, the flood situation from the year 2010 was reconstructed, establishing the basis for a construction of the flood hazard maps and flood risk management plans. The problem was solved with a MODFLOW numerical model using the Groundwater Modeling System.
The contribution is dealing with run-off conditions on the lower part of the Ondava River as the capacity of the river bed is insufficient at high flow rates. The reason for the proposed research was the flood situations when protection dikes were breached. For mathematical modeling of flood wave progress, the HEC-RAS software has been applied coupling 1D and 2D modeling procedures. Results of the mathematical model of the surface water level regime in the Ondava River were compared with measured values and afterwards it was used to design further flood protection measures utilizing the existing drainage channel system and pumping stations, as well.
The paper deals with an analysis of a drought in the small basin of the Gidra River in Slovakia due to problems with the abstraction of water from small reservoirs and ponds. A detailed hydrological assessment of the M-daily discharges for a long-term period was based on a dataset from the only gauging station on the upper part of the river. Because of the existing water structures with prescribed operations during the year, hydrometric and geodetic measurements were taken by the authors. The solution to this problem represents the conditions for the minimum required Q355 discharge in the river anytime and anywhere. This can only be solved with a master operational manual for the whole river to be able to flexibly react to the current hydrological situation.
The overall purpose of this research was to model flow extraction from several groundwater network wells to control the excessive level of groundwater. The study was conducted in the Nitra Industrial Park, which is located in the northern part of the town of Nitra, where the confined groundwater table is situated very close to the terrain. The area of interest is a plain with a mean elevation of 140.0 m a.s.l. The groundwater can rise up to 140.5 and 143.0 m a.s.l. during the dry season, extreme climate conditions, or a flood wave in the Nitra River, respectively. In order to keep the level of the piezometric head below 140.0 m a.s.l. (as requested by the investor), there are already 38 wells realized around the area of interest with the proposed pumping rates.
The numerical groundwater modeling was applied using the TRIWACO simulation package for the given hydrological, geological and hydro-geological conditions. The transient simulation takes into account a Q1000 historical discharge in the Nitra River and its possible impact on the groundwater. The paper will present numerical modeling results on the design of a drawdown system to lower the groundwater level to an acceptable elevation as well as parameters and uncertainties for the design purpose.
The water sources located on the inland islands on the left side of the Danube River as well as water sources located on the right bank of the Danube River in the Pečniansky forest have an irreplaceable function in terms of supplying the population in Bratislava with drinking water. There are 80 wells in these mentioned areas operated by the Bratislava Water Company. In order to maintain the actual functions of the water resources, it is therefore necessary to assess the impact of the proposed construction of the multi-purposed structure ‘Hydraulic structure Bratislava — Pečniansky forest’ on these water sources.
The new proposed railway network in the city of Bratislava, which is supposed to be connected to the airport, is an integral part of Trans-European Network for Transport .Certain section of the planned railway should be constructed along Carpathian Mountains through underground tunnels. However, the construction of this underground tunnel will adversely affect the groundwater flow regime. Therefore, it was necessary to establish a 2D finite element numerical model to evaluate the implementation of this railway tunnel on the groundwater regime as well as means of technical measures to reduce the impacts. The paper presents the model result, analyses, prognosis as well as possible methods to control the groundwater level regime in the aquifer that could be affected by the railway tunnel construction.