Water balance calculation method for urban areas examples from Hungary

Abstract 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 tested in other Hungarian cities where underground structures are common, such as Eger, Pécs and Veszprém. The calculation considers both natural and anthropogenic water sources. Beside the commonly-used natural factors such as precipitation, evaporation, runoff, infiltration, etc. it also employs input parameters such as broken pipelines and sewer systems. The water losses of these waterworks significantly influence the natural water balance and provide additional and very often significant water input into the water system. The new method is of great importance in designing and planning remedial actions for historic cities, where the built environment, cellars and natural caves are endangered by infiltrating water. Another feedback of the method is the application of the results in the long-term planning strategy of public works supplying or using water (water works, sewer system and energy sector)

Modelling Methods Attached to the Research of Groundwater Flow in Fractured Rocks – Theories, Laboratory and Numerical Modelling

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 The laboratory model originally made by Öllős and Németh in 1960 was rebuilt in MODFLOW-CFP. The usability of both modelling method was analysed. Based on the experience of this modelling an existing cave system was modelled with CFP. The Molnár János Cave – a karst cave almost filled with water – was analysed with the tool of numerical modelling to better understand the flow in cave conduits

Validation of a Physical and Numerical Model to Solve Problems of Seepage Flow

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. The model tests provide that can be applied for estimating permeability of different soils. In a physical model medium-grained sand was tested in the laboratory, for understanding the effects of different flow rates on the validation of the measurement result, the numerical simulation of the physical model was constructed using FEFLOW. Two model variants were developed and both variants were calibrated and validated. Subsequently, the results were converted to real variables based on the model laws. The physical model provides the flow rate of the well in medium-grained sand with sufficient accuracy if the real size of the drawdown is between 0,5 and 1,7 m

Water level fluctuation in karst aquifers in the Transdanubian range (Hungary)

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 to the monitoring wells near Tata and data series of the Molnár János-Cave in Budapest. By the help of available water level data the periodic fluctuation of the karst water surface is identified in connection with tidal effect and the influence of barometric pressure

Determination of the transmissivity of a karstified aquifer from mine dewatering data

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 processes was emphasized. Although the mines were abandoned the data sets could be a great base of additional investigation about the karstified aquifers. This paper presents the evaluation of dewatering data as pumping test data by using many methods

A Gellért-hegyi sikló mérnökgeológiája

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. Az eocén márga alatt fúrással feltártuk a hegy fő tömegét alkotó triász dolomitot, amelyben karsztos üregeket mutattak ki a vizsgálatok. A márga dőlése változó a fúrások alapján átlagosan 10-15°-os, de helyenként 30-40°-os meredek dőlésű rétegeket is találtunk. Tektonizáltságára jellemző, hogy réteg menti vetők, csúszólapok tagolhatják, de meredek, 60-75°-os kalcittal részben kitöltött repedéseket is találtunk. A márga felső zónája gyenge (RMR IV. oszt), mélyben fekvő cementált zónája jó (RMR II. oszt) paraméterekkel rendelkező kőzettestnek tekinthető. A 2 éves adatsorok és a vízszint mérések alapján meghatároztuk a maximális várható vízállást