Géza Hajnal

Budapest University of Technology and Economics · Department of Hydraulic and Water Resources Engineering

The coefficient of permeability (k value) is an important parameter in civil engineering practice, in hydrology and hydrogeology. It can be determined by field test or by means of laboratory testing. The goal of this paper is to assess this parameter by creating a laboratory model and by validating its results using finite element computer code. Th...

Monitoring of the karst aquifers of Transdanubian Range gives an opportunity to analyze not only the long-term water level and spring discharge changes, but also the short-term fluctuations. In this paper observations related to increasing karst water level in the region of Tata are presented. Short-term karst water level fluctuations are compared...

The forty years of intensive mine dewatering in the Transdanubian Range contributed to getting high quality and large amount of data about the karstified aquifers, which could not be gained in any other way. In addition to providing the claimed depression to the safety mining under the original karst water level, the scientific investigation of the...

There are serious efforts worldwide to better understand and model groundwater flow in fractured rocks and karst aquifers. This study summarizes the major theories and idealizations used for describe flow in fractured rocks and presents a laboratory model and numerical models which were made for this purpose. The laboratory model originally made by...

Traditional groundwater flow modelling is based on the Darcy's law which is valid when the flow is laminar. However, the water flow in fractured aquifers can be non-laminar in discontinuities and in this case the Darcy's law is not valid. That is why a numerical solver is needed which is able to model both laminar and non-laminar flows. The MODFLOW...

The impact of climate change constitutes a new agenda for water resources management and disaster prevention. Changes in water availability, and/or flood risks due to extreme weather conditions are causing problems for water resource managers and engineers. The city managers in Eger, Hungary decided to evaluate the impact of these conditions on Ege...

This study aims to test and compare the applicability and performance of two different hydrological model concepts on a small Hungarian watershed. The lumped model of HEC-HMS and the semi-distributed TOPMODEL have been implemented to predict streamflow of Bükkös Creek. Models were calibrated against the highest flood event recorded in the basin in...

To determine the Darcy’s coefficient of permeability are several methods available. Empirical and deterministic calculation methods were developed of which applicability and accuracy depends on the available data and the type of investigated soil. Both field and laboratory investigations are common. In practice of civil engineering it is most essen...

To determine the Darcy’s coefficient of permeability are several methods available. Empirical and deterministic calculation methods were developed of which applicability and accuracy depends on the available data and the type of investigated soil. Both field and laboratory investigations are common. In practice of civil engineering it is most essen...

Increased population growth and changing environmental conditions have focused attention on sustainability of karst spring flow. In Hungary, the quality of karst springs is acceptable for drinking water supply; the only treatment it needs is the disinfection. Aggtelek is one of the best-studied karst regions; a hydrologic monitoring network was bui...

To determine the Darcy's coefficient of permeability are several methods available. Empirical and deterministic calculation methods were developed of which applicability and accuracy depend on the available data and the type of investigated soil. Both field and laboratory investigations are common. In practice of civil engineering it is most essent...

Az építőmérnöki gyakorlatban egyre gyakoribb feladat a talajvízfelszín alatti rétegek szivárgási tényezőjének meghatározása. A mélyépítési munkák költségbecslésekor a munkagödör víztelenítési módját kívánja előre meghatározni a beruházó, a másik gyakori cél pedig a kitermelhető vízkészlet megállapítása a tervezett épülethűtéséhez-fűtéséhez. A geote...

A new water balance calculation has been worked out that considers the effect of urbanization. This calculation method was applied to evaluate the water balance of the historic center of Budapest, the Buda Castle Hill, where an intensive network of cellars is found. The method, a combination of hydrogeologic tests and field measurements, was also t...

A Gellért-hegyre tervezett sikló és a mellette kialakítandó garázs mérnökgeológiai és hidrogeológiai viszonyait mutatja be a cikk. A terület földtani viszonyainak megismerésére 10 magfúrás, kutató aknák készültek. A sikló nyomvonal budai márgában fut, a kőzet felső zónája sárga agyagos, majd ez alatt szürke cementált mészmárga rétegek találhatók. A...

In the previous centuries, a lot of energies were expended on the scientific knowledge of the Castle Hill, Buda, declared a part of the World Heritage, however only few scientist carried out researches on the hydrogeology of the Hill and out of them only the results of Kessler's studies survived in a systematized form. The author has been dealing w...

The Castle Hill of Buda is a Word Heritage Site and is located in Budapest capital of Hungary. The hill is mainly composed of Eocene marls, Oligocene clays and covering fluvial sediments and travertine. In this area an extended three-level cellar system is found. The upper two cellar levels are artificial ones while the lowest one is an artificiall...