Ervin Pirkhoffer

Mapping direct human impact on the topography of Hungary

Summary. Similarly to other European countries, human impacts of various types are discernible in all regions of Hungary. Restricting the infl uence of human activities to direct transformation of topographic conditions, primary and secondary landforms created, the main categories of symbols included in the legend of an overview map refer to water management (fl ood-control dykes, dams and canals); to housing development, industry and transportation (landfi lls, sealed, levelled and ter-raced surfaces; motorway/railway embankments and cuts), to agriculture (terraces, hollow roads) as well as to other human activities with geomorphic impact (military and sports facilities). Th e map symbols are designed to provide some indication of the relative extent of human action and the size of anthropogenic landforms. Usually two (large or small scale impact) or three (large, medium or small scale) relative size categories are applied. Th e data base for the map is processed at 1:500,000 scale, allowing some reduction in scale for fi nal publication in an international ”Atlas of Human mpact I on Topography” under preparation by members of the IAG Working Group ”Human Impact on the Landscape”, created in 2005.Zusammenfassung.

Analysis of soil boundary conditions of flash floods in a small basin in SW Hungary

Flash floods are one of the most significant natural hazards of today. Due to the complexity of flash flood triggering factors, to prevent or mitigate flood triggered losses, numeric model based flood forecasting models are capable tools to predict stream water levels. The main goal of the current research was to reproduce two flow peaks with the HEC-HMS rainfall-runoff model and test the model sensitivity for various input parameters. To obtain sufficient input data, we monitored soil depth, maximum infiltration rate, soil moisture content, rainfall, time of concentration and flow. To obtain input data, parameters were calculated, measured in the Sás Valley experimental watershed (SW Hungary) or optimized with the built in function of the HEC-HMS. Soil moisture was monitored in the 1.7 km2 pilot catchment over the period between September 2008 and September 2009. HEC-HMS had a good performance reproducing the two events, however simulated flow time series are highly influenced by the antecedent soil moisture, infiltration rate and canopy storage. Outflow modeled data were verified for two flood events (June 4, 2008 and July 9, 2009). The HEC-HMS was over-sensitive for input soil moisture and with increasing input rainfall and increasing outflow, larger simulation errors were observed.

Hydromorphological assessment of the lower Hungarian Drava section and its floodplain

The hydromorphological properties of rivers and their floodplains receive increased attention both in basic research and water management. A comparison of hydromorphological parameters before and after river regulation (involving floodplain drainage) provides important information for river management, particularly floodplain rehabilitation. The paper assesses a selected reach of the Drava River and the corresponding floodplain utilising two international approaches, the REFORM framework and the Italian Morphological Quality Index.

Playing on reality: do geomodels improve the perception of geographical terms?

ABSTRACT Remodeling of geography education has been an ongoing challenge recently. Constructivist pedagogy, employing tools of problem and model-based learning, offers new opportunities to meet these challenges. Geomodels, flumes and stream tables may ease the understanding of geographic processes through hand-on-experience for students. With a computer-controlled geomodel, we analyzed the development of 36 high school students’ terminology in the fields of potamology and remote sensing. Potamology terms, provided after the experimental session, were more focused and reflected the information perception and fixation during the experiment. Three weeks later the terminology of the students indicated a partial fixation of the relevant terms. When students’ terminology on remote sensing was analyzed, the pre-experiment terms were loosely connected to the topic. Over the class, students’ terminology increased in the field of potamology. Although it became more topic-specific and focused, students’ remote sensing terminology still contained a large number of off-topic terms by the end of the experiment and three weeks later. Our findings revealed one of the major weaknesses of the Hungarian educational system, i.e. teachers are forced to follow the conventional geographical curricula, therefore hindering their adaptation to cutting-edge educational methods and the learning-by-doing approach of the Western European and North American syllabi.

Interpolation and 3D visualization of soil moisture

Adaptation to climate change demands the optimal and sustainable water management in agriculture, with an inevitable focus on soil moisture conditions. In the current study we developed an ArcGIS 10.4. platform-based application (software) to model spatial and temporal changes in soil moisture in a soy field. Six SENTEK Drill & Drop soil moisture sensors were deployed in an experimental field of 4.3 hectares by the contribution of Elcom Ltd. Soil moisture measurement at each location were taken at six depths (5, 15, 25, 35, 45 and 55 cm) in 60-minute intervals. The model is capable to spatially interpolate monitored soil moisture using the technique. The time sequence change of soil moistures can be tracked by a Time Slider for both the 2D and 3D visualization. Soil moisture temporal changes can be visualized in either daily or hourly time intervals, and can be shown as a motion figure. Horizon average, maximum and minimum values of soil moisture data can be identified with the builtin tool of ArcGIS. Soil moisture spatial distribution can be obtained and plotted at any cross sections, whereas an alarm function has also been developed for tension values of 250, 1,000 and 1,500 kPa.

Kapos Valley: The Most Asymmetrical in Hungary

Neotectonic movements often result in marked large-scale asymmetry of river valleys. The characteristically rectangular (“chequerboard”) drainage pattern of Southern Trandanubia has provoked discussions among Hungarian geologists and geomorphologists for more than a century. In the centre of this area is the Kapos River valley, the asymmetry of which is obvious to any visitor. Although this asymmetry has been undoubtedly controlled by neotectonic movements to a large extent, it is probably also enhanced by geomorphic processes. The degree and distribution of asymmetry is quantified using different morphometric indices calculated from a Digital Elevation Model. An overview of the tectonic models proposed to identify the reasons behind asymmetry in the study area is also presented. It is pointed out that the asymmetry is associated with the alignment of two tectonic lines crossing the catchment and also manifested in the planform of the valley floor (i.e. in the shape of the morphological floodplain).

Flash Flood Analysis for Southwest-Hungary

The 15–18 May 2010 flood events on the watershed of the Bukkosd Stream, SW Hungary, are described, their general topographic and hydrologic characteristics are analyzed using the HEC-HMS numeric runoff model, and geomorphological impacts are surveyed. In addition to extreme rainfall volumes, the major reasons found to contribute to extreme impoundment were the fluctuating and locally reduced width of the valley, the confluence of tributaries, which create intermittent bottlenecks for drainage, and high soil moisture contents, which also caused slope instability in deeper soil mantle. Flash flood hazard is closely associated with landslide hazard in upland valleys.