River bathymetry has a crucial role in numerical modelling of flow hydrodynamics. The aim of the present study is to (1) investigate the capability of three different methods to trace the river bed, with the geodetic data derived from in situ survey of the river bed topography to be used as reference data, and moreover (2) assess the impact of the different river geometries on the performance of a one‐dimensional (1D) model of flood hydraulics. The Hydrologic Engineering Center's River Analysis System (HEC‐RAS) hydraulic model, in particular, calibrated and validated on hydrometric data uses a number of cross‐sections derived from aerial laser scanning (ALS), artificial sinking of riverbed, and acoustic Doppler current profiler (ADCP) methods. Water level, discharges, and flood extent derived from the model for 3 N‐year floods (Q1, Q50, Q100) were evaluated while the extent of the inundation areas were exported into geographic information systems for visualisation and interpretation of the findings. Case study area is a 2.2 km river section of the Otava River (Czech Republic), with a history of flood events. The results showed that ALS data need further processing when dealing with the riverbed zone, while ADCP presented high correlation to the reference model.

Topographic data plays an essential role in hydraulic modelling of floods. A highprecision digital elevation model (DEM) including river bathymetry (bed topography) is required. DEMs can be derived from such various data sources as ground surveying or remote sensing techniques. This study is focused on (a) the DEM error that results from the inability to scan the morphology of the channel using remote sensing methods, and (b) assessment of its impact on the results of a onedimensional (1D) hydraulic model. DEMs produced by remote sensing techniques were tested in combination with ground surveying and by software-updated remote sensing data. Differences in riverbed representation and thalweg position were evaluated. The 1D hydraulic model HEC−RAS was chosen to determine the impact of various DEM sources on the hydraulic quantities (water surface elevation, inundation area). The study was carried out on a reach of the River Vltava (Czech Republic). The best results were achieved by DEMs that combined remote sensing data with ground mapping. Good results also were obtained using software-updated remote sensing data. Neglecting of cross-sectional area in remote sensing data has an important impact on the results of hydrodynamic models. K E Y W O R D SDEM, digital elevation model, floods, hydraulic modelling, river bathymetry

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The contemporary regional geography paradigm is characterized by emphasizing the socially constructed nature of regions. However, the discussion on the conceptualization of region is very rich, it does not reach universal conclusion. Such a universal conceptualization is probably neither possible nor desirable. This paper aims to contribute to the ongoing discussion. It examines the various approaches towards region with special focus on the conceptualization of the institutionalization of the region based on the heuristic literature review and it attempts to propose more complex (but not ultimate) theoretical conceptualization of region that should enable to bridge the duality of region; addressed as an "animate", constantly changing, phenomenon which also makes it a resource for regional actors to meet their particular goals, one that people may perceive and feel attached to while further mediating their images thereof. The paper builds upon the Lefebvre's theory of the societal production of space and the Paasi's theory of the institutionalization of region and presents the idea of the societal production of region. It argues that any complex approach to region must incorporate three levels of region: "given" (practice of region), "made" (representation of region) and "perceived" (idea of region). Better understanding of the concept of region is still more necessary and relevant especially due to the increasing pressure on the applicability of regional research. Thus, the paper suggests the closer insight into the interrelation of three mentioned levels of region is crucial from the view of the contemporary state of art. This text is also published in Czech as the official on-line supplement of the article.

Knowing the extent of inundation areas for individual N-year flood events, the specific flood scenarios, and having an idea about the depths and velocities in the longitudinal or transverse water course profile provided by hydrodynamic models is of key importance for protecting peoples' lives and mitigating damage to property. Input data for creating the watercourse computational geometry are crucial for hydrodynamic models. Requirements for input data vary with respect to the hydrodynamic model used. One-dimensional (1D) hydrodynamic models in which the computing track is formed by cross-sectional profiles of the channel are characterized by lower requirements for input data. In two-dimensional (2D) hydrodynamic models, a digital terrain model is needed for the entire area studied. Financial requirements of the project increase with regard to the input data and the model used. The increase is mainly due to the high cost of the geodetic surveying of the stream channel. The paper aims at a verification and presentation of the suitability of using hydrological measurements in developing a schematization (geometry) of water courses based on topographic data gained from aerial laser scanning provided by the Czech Office for Surveying, Mapping and Cadastre. Taking into account the hydrological measurement during the schematization of the water course into the hydrodynamic model consists in the derivation of flow rate achieved at the time of data acquisition using the method of aerial laser scanning by means of hydrological analogy and in using the established flow rate values as a basis for deepening of the digital terrain model from aerial laser scanning data. Thus, the given principle helps to capture precisely the remaining part of the channel profile which is not reflected in the digital terrain model prepared by the method of aerial laser scanning and fully correct geometry is achieved for the hydrodynamic model. Znalost rozsahu záplavových území pro jednotlivé N-leté povodňové události a konkrétní povodňové scénáře, včetně získané představy o hloubkách a rychlostech v podélném či příčném profilu vodního toku, které poskytují hydrodynamické modely, zaujímá výsadní postavení z pohledu ochrany životů a zmírnění škod na majetku občanů. Stěžejním faktorem pro tvorbu hydrodynamických modelů jsou vstupní data pro vytvoření výpočetní geometrie vodního toku. Požadavky na vstupní data se liší s ohledem na použitý hydrodynamický model. Jednorozměrné (1D) hydrodynamické modely se vyznačují nižšími požadavky na vstupní data, kdy výpočetní trať je tvořena příčnými profily koryta, naproti tomu u dvourozměrných (2D) hydrodynamických modelů je nutné sestavit pro celé řešené území digitální model reliéfu. S ohledem na vstupní data a použitý model roste i finanční náročnost celého projektu. Nárůst finančních prostředků je způsoben především vysokými náklady na geodetické zaměření koryta toku. Cílem příspěvku bylo ověřit a prezentovat vhodnost využití hydrologického měření při tvorbě schematizace (geometrie) vodních toků na podkla...

An appropriate digital elevation model (DEM) is required for purposes of hydrodynamic modelling of floods. Such a DEM describes a river's bathymetry (bed topography) as well as its surrounding area. Extensive measurements for creating accurate bathymetry are time-consuming and expensive. Mathematical modelling can provide an alternative way for representing river bathymetry. This study explores new possibilities in mathematical depiction of river bathymetry. A new bathymetric model (Bathy-supp) is proposed, and the model's ability to represent actual bathymetry is assessed. Three statistical methods for the determination of model parameters were evaluated. The best results were achieved by the random forest (RF) method. A two-dimensional (2D) hydrodynamic model was used to evaluate the influence of the Bathy-supp model on the hydrodynamic modelling results. Also presented is a comparison of the proposed model with another state-of-the-art bathymetric model. The study was carried out on a reach of the Otava River in the Czech Republic. The results show that the proposed model's ability to represent river bathymetry exceeds that of his current competitor. Use of the bathymetric model may have a significant impact on improving the hydrodynamic model results.

The paper deals with the issue of drinking water supply as a factor for changing housing and presents selected results of the implemented questionnaire survey in the Czech Republic from the perspective of Czech inhabitants over the age of 15. The paper presents the particular outputs of project no. TL02000060 entitled "Availability of Drinking Water for Inhabitants of Small Municipalities as an Indicator of the Socioeconomic Development of Society", which was created with the support of the Technology Agency of the Czech Republic.

Of all natural disasters, floods represent the most serious threat to the territory of the Czech Republic. This is given by the situation of the Czech Republic at the continental as well as the worldwide scale. At present, the design of anti-flood measures is mostly based on technical measures, without considering improvements in the hydromorphological status according to the Framework Directive on Water Management and without considering the natural transformation of flood discharge in the alluvial plains of water courses. This report presents a design for the optimization of anti-flood measures in the pilot catchment of the Litavka River, in which we propose particular measures for the catchment for its entire surface while providing a good hydromorphological status. We also wanted to quantify the proposed measures leading to the increased retention and accumulation capacities of the catchment area.