Hydraulics, hydrology and hydrogeology

Fishponds as an element of surface waters network – overview, history, function

Historically, fishponds are a part of our landscape and Christmas carp is also a part of our culture. This paper describes the history of fishpond management and the different functions of fishponds – the development of fish production as food, the influence on quality of surface waters, the influence on climate and on hydrological regime of the landscape, and the issue of fishpond sediments – their removal and further use. As there is no general pond register in the Czech Republic, so (as part of the DivLand project) we created the Map of water bodies and fishponds in Czech Republic, based on the ZABAGED (primary base of geographical data
in the Czech Republic). For water bodies with an area over 1.0 ha, a public database (xls) was created; bodies over 5.0 ha were classified into groups (fishponds, reservoirs, flooded areas, lakes). The database also contains accessible data on the quality of fishpond sediments. Fishpond sediments are a favourable material for improving the quality of agricultural soils; problems with their use are mostly technical and economical.

Assessment of the status of surface water bodies in the Czech Republic for 2019–2021

The article presents the results of the assessment of the status of surface water bodies in the Czech Republic for 2019 to 2021. The status assessment has been carried out by T. G. Masaryk Water Research Institute, p. r. i. (TGM WRI), Biology Centre CAS, and the Czech Hydrometeorological Institute (CHMI). The status of the water bodies was evaluated according to monitoring data from the River Boards state enterprises and – in the case of selected priority substances in biota – from the CHMI. The assessment procedures were the same as in the previous status assessment for 2016 to 2018, which was incorporated into the river basin management plans for the third planning period. The article focuses on presenting the results of the assessment, which was prepared by the TGM WRI. It is a summary assessment of the ecological and chemical status of water bodies, an evaluation of chemical and physico-chemical indicators and a comparison of the results of the assessment for 2019 to 2021 with the assessment for 2016 to 2018. In 2019 to 2021, good chemical status was not achieved in 57.6 % of water bodies; the problematic pollutants are mainly polyaromatic hydrocarbons; in the ‘biota’ matrix there was also mercury and brominated diphenyl ether. Good ecological status/potential has not been achieved in 92.3 % of water bodies; the problematic indicators are mainly biological quality elements and phosphorus.

Verifying the applicability of methods for modelling erosion and connectivity of sediments in the Slavíč catchment in the Moravian-Silesian Beskydy mountains based on geomorphological mapping of fluvial processes

As part of the research activities of the Hydrology Department of CHMI Ostrava, field investigations and measurements are being carried out in several catchments to verify the outputs of GIS tools, empirical formulas, and mathematical models focused on surface runoff, fluvial erosion, and sediment transport. The main emphasis is placed on the influence of deforestation and land use changes on rainfall-runoff relations and fluvial erosion, especially within the framework of the NAZV “DEFOREST” and “CLIMCFOR” projects, in which CHMI collaborates with the Forestry and Game Research Institute (VÚLHM), the Bishopric of Ostrava-Opava, and Water Management Development, and Construction joint stock Company (VRV). The presented article deals with the possibilities of analysing fluvial processes and disconnectivity of flows in the Slavíč catchment in the Moravian-Silesian Beskydy Mountains. ESRI ArcGIS and GRASS GIS tools were used for these analyses. Field verification of outputs took place at several sampling points within the main stream Slavíč.

Interview with Mrs. Prof. Dr.-Ing. Birgit Vogel, ICPDR Executive Secretary

One of the biggest international activities in water protection is the multilateral cooperation in protecting the Danube. It originally started in the 1980s in the form of the Declaration signed in Bucharest in 1985, which concerned the Danube River itself. In 1992, at the initiative of the European Communities, the internationally supported Danube Environment Programme was launched, covering the entire Danube basin including its tributaries. In parallel, work was underway to prepare a Convention on Cooperation for the Protection and Sustainable Use of the Danube. The Convention was submitted for signature in Sofia on 29th June
1994 and entered into force on 22nd October 1998. The Contracting Parties to the Convention are Bosnia and Herzegovina, Bulgaria, Croatia, the Czech Republic, Germany, Hungary, Moldova, Slovakia, Slovenia, Serbia, Montenegro, Romania, Ukraine, and the European Union. In August 2022, for the first time, a woman became the Executive Secretary of the International Commission for the Protection of the Danube River (ICPDR) – Prof. Dr.-Ing. Birgit Vogel.

Jizera Mountains researchers in Podbaba

On 25th January 2024, a seminar Meeting of researchers in the Jizera Mountains was held in the conference centre of T. G. Masaryk Water Research Institute (TGM WRI) in Prague. It presented (mainly long-term) research projects implemented in the Jizera Mountains and focused on atmospheric precipitation, forest soils and forests, waters and their biota in recent decades, i.e. from peak acidification to current phenomena associated with climate change. However, no less important was the personal meeting of people who research, permanently work or live in the Jizera Mountains and are interested in the development of the situation in this area, as well as the final debate open to all.

Disappeared pond system in the lower Doubrava river

This article presents the results of research of the pond landscape development in the lower Doubrava river. The results are based on the interpretation of archival map documents and the current state of the site. On the map of the 1st military mapping (1764–1768), a system of thirteen ponds was recorded on the right bank of the Doubrava river. There were three ponds on the left bank of the Doubrava river. On the map of the 2nd military mapping (1836–1852), only four ponds were recorded on the right bank of the Doubrava river and only two ponds on the left bank of the Doubrava river. Of the historic pond system, only Koukalecký pond and a pond near Žehušice chateau have survived to the present day. On the 1st military mapping map, the total approximate area of the ponds was 449 ha, on the 2nd military mapping map it was 107 ha, and today only 0.91 ha.

Weisshuhn flume in Žimrovice

The CHMI Ostrava branch has repeatedly had the opportunity to measure water flumes, mostly during verification measurements of minimum residual flows, measurements for structural wear, or revision of flow measurement curves. As part of these measurements, it was a very valuable experience to get to know these undoubtedly very interesting waterworks, which are often also technical monuments. Part of these activities includ-ed measurements and subsequent modelling of Weisshuhn flume in Žimrovice. This article summarizes and comments on the partial results of these activities. One of the tasks was to determine the critical points in terms of water losses in the Weisshuhn flume. Although these phenomena do occur, the numbers are not significant, as illustrated by the results of measurements and modelling. Different types of devices were used for the measurements; mostly ADCP devices, namely RDITeledyne StreamPro, SonTek RiverSurveyor M9, and SonTek Teledyne RS5. MIKE 11.

Water infiltration will help with heat, drought, and floods

New predictions of climate change impacts in the Czech Republic show that rainfall will increase slightly in the future. However, in combination with the expected increase in temperature, evaporation will be higher, which will lead to long-term water shortage. Forecasts also say that rainfall will be distributed differently during the year, which in practice means that long periods of drought will alternate with sudden torrential rainfall. But this is nothing new. In the Czech Republic today, there is already a lack of water; it lies on the main European watershed, and we are therefore highly dependent on rainwater. In the past, unfortunately, we have modified cities and the countryside in such a way that rainwater was quickly diverted away – by channelling watercourses, by farming methods, and by creating sewers. Adaptation measures to climate change in the field of water management can significantly increase the sustainability of water resources, reduce the risk of floods, and ensure water even in times of drought.

Protected areas of natural water accumulation – their meaning in the current system of water environment protection

This article discusses the development, management, and use of the landscape in the form of a declaration of a Protected Area of Natural Water Accumulation (CHOPAV). It examines the importance of this method of protection in the water protection system under the requirements of the Water Framework Directive and other European directives which have been incorporated into the legislation of the Czech Republic. It looks at the possibilities of using this tool in water management to deal with problems caused by climate change. Based on the research and analysis carried out, the article recommends modifications to the CHOPAV regime and area modifications, as well as expansion to other sites.

Development of land use and impact on water resources of hydrogeological unit 4232 Ústecká syncline in the Svitava river basin

The research area of hydrogeological unit 4232 Ústecká Syncline in the Svitava river basin (Ústecká synklinála v povodí Svitavy) is an important area of underground drinking water sources. These resources are of the highest quality and among the most abundant resources in the entire Czech Republic. The development of land use is closely connected with the development of settlements and industry (textile) in the research area, which in their importance far exceeded the borders of the region. Gradual development created pressure on natural resources, especially water; the demands on the quantity of service and drinking water increased, while the quality of water was affected by industrial and agricultural pollution. Despite the observed decrease in population in the last twenty to thirty years, we can see the expansion of settlements, mainly due to new construction on agri-cultural land, which is slightly compensated by the expansion of permanent grasslands and forests. With regard to current and future climate change, this increase, together with a slight increase in water bodies, can be considered as a positive phenomenon.

Use of effect-based methods to assess surface water status

This article deals with the use of effect-based methods for the qualitative assessment of the state of surface waters in the context of Directive 2000/60/EC establishing the framework for Community activity in the field of water policy and the upcoming amendment to Directive 2008/105/EC on environmental quality standards. The implemented monitoring of priority substances and specific pollutants is not able to capture all sources of pollution that negatively affect surface water quality. Likewise, current practice does not allow a comprehensive assessment of mixtures, including emergent pollutants, metabolites, and transformation products of substances on water quality. Effect-based methods are a suitable tool for ecotoxi-cological evaluation of pollution, which considers all substances contained in the sample and possible effects of mixtures (synergistic effects). They thus provide important additional information for the results of the assessment of the state of surface water bodies.

Interview with prof. Ing. Pavel Pech, CSc., professor at the Czech University of Life Sciences Prague

the future be over water rather than oil and land? Why is he more afraid of genes than climate change? And is it better to build dams and large water reservoirs, or establish ponds, wetlands, and pools? What is his opinion on artificial intelligence? These are just some of the topics that I discussed with prof. Ing. Pavel Pech, CSc., long-time head of the Department of Water Resources and Environmental Modeling at the Czech University of Life Sciences (CULS). “I’m from Hnojárna,”* he says about himself with a smile, and it does not sound pejorative at all – after all, he is the founder of the Faculty of Environmental Sciences at CULS in Prague.

Looking back at the National Dialogue on Water 2023

After a four-year break caused by the covid pandemic, the National Dialogue on Water took place on 25–26th October 2023, this time in the Skalský Dvůr hotel in Vysočina. The event was organized by the T. G. Masaryk Water Research Institute, p. r. i. (hereinafter TGM WRI) in coop-eration with the Czech Scientific and Technological Water Management Company (Česká vědeckotechnická vodohospodářská společnost, z. s.) The main theme of the event was a comprehensive approach to the protection of drinking water sources. This topic was addressed by a large number of experts from the field of water management (118 participants), whether it was representatives of the Ministry of the Environment (MoE), Ministry of Agriculture (MoA), Ministry of Health, state-owned River Basin State Enterprises, the Czech Hydrometeorological Institute (CHMI), water authorities, operators of water supply and sewerage systems (VaK), mayors, private companies, hydrogeologists, and others.

Kozmice bird meadows and their importance for nature and landscape

Alluvial wetlands and alluvial meadows (often referred to as “wet” in the literature) are one of the types of habitats that, with the gradual develop-ment of the cultural landscape, suffered the greatest transformation and often complete disappearance; in the Czech Republic, the most significant transformation by the transfer to field crops together with land improvement peaked roughly in the 1970s. Discussions about the importance of wetlands have, however, been revived in different periods; the factors that trigger these discussions are mainly floods and drought, which is clearly indicated by the drought that started in 2015. In their name, alluvial wetlands and meadows indicate that they are situated in a river landscape and are in periodic or constant contact with the surface water of larger rivers and groundwater, including the hyporeal. It is therefore obvious that these landscape elements are at least locally important for the cycle of water and chemical substances in the river landscape.

Direct monitoring of water vapor from the free water level of the Vavřinecký pond and its influence on the hydrological balance

With increased average air temperature, there is an increase in water vapour from a water surface. Between 2020 and 2022, evaporation from the water surface was observed with a floating evaporimeter at Vavřinecký pond in the Central Bohemian region. A floating evaporimeter monitors evaporation from the water surface along with basic meteorological quantities directly on the surface of the water reservoir, so its results should be more accurate than calculations based on data from nearby meteorological stations. The results show that in all three years evaporation exceeded precipitation by more than 100 mm between April and September. However, the issue of the influence of small water reservoirs on the hydrological balance is a very complex topic, where the assessment of negative and positive effects is not always black and white and requires detailed investiga-tion.

Drought warning system and local threshold limits

Droughts and floods are extreme hydrological phenomena that are currently increasing in frequency due to the growing impact of climate change, and can have significant effects on our lives. Within the “PERUN” research project, an assessment of drought conditions and their development in the Czech Republic is being developed, along with the innovation of the warning system by the Czech Hydrometeorological Institute (CHMI). Drought is a natural phenomenon characterized by a gradual onset, long duration, and low dynamics, which requires a specific approach. The amendment to the Water Act introduces the obligation of regular reporting on drought and the establishment of a predictive service to be conducted by CHMI. Tools are being developed for long-term prediction of water resource conditions and a methodology for drought and water scarcity management plans. These plans aim to ensure water supply, protect the environment, and minimize the economic impacts. The decision-making body for issuing measures based on the drought plans is the Drought Commission, which operates at the regional level. The warning information is available on the HAMR web portal, which also displays local threshold limits for individual water resources.

Protected areas for surface water accumulation from a hydrogeologist’s the point of view – the effect of possible realization of surface water accumulation on hydrogeological conditions

Suitable areas for the accumulation of surface water have been defined in the Czech Republic, potentially serving mainly for the supply of potable water and for mitigating the adverse effects of floods and drought. The sites are listed in the General Scheme on the Accumulation of Surface Water, which was obtained by the Ministries of Agriculture and the Environment following the previous long-term territorial protection of prospective water reservoirs. Before any decision to build these reservoirs, it is necessary to assess the project from various points of view. This article presents an evaluation of selected sites from a hydrogeological point of view. Among other things, it deals with the analysis of the location of potential res-ervoirs in the hydrogeological environment, the effect on the quantity and quality of groundwater, and the potential impact on the used groundwater resources. After the construction of the reservoirs, the groundwater level of the shallow aquifer will rise, and consequently, groundwater storage will also increase. However, it is necessary to assess the sites individually; there are often potentially negative effects of future reservoirs on groundwater.

Study of stream morphological changes and its application in the design of environmentally acceptable channels

Climatic change is manifested in a number of places by significantly spatially localized torrential rainfall with a short duration, but with great inten-sity. One of the expected consequences of this type of precipitation is the occurrence of flash floods, characterized by a sharp rise from the value of the normal flow to the value of the peak flow and a rapid decrease again. The consequence of this type of short episodic floods is the initiation of morphological transformations in the beds of smaller and medium upland streams, often with devastating effects for the section of the watercourse channel. The article summarizes research on the formation and development of a scour hole in the section at the transition from a lined riverbed with fixed bed and banks to the riverbed with loose channel boundry which can be transformed morphologically in an uncontrolled manner. In this re-search, the main attention was paid to the formulation of a parametric model of the scour hole morphological development at the transition between a lined and an unlined channel. The results of this model can be used both to understand the hydraulic-morphological processes that occur at the site of a sudden river bed change, and for the practical design of restoration modifications to the river bed at the transition from a fully lined to an un-lined river bed without any protective measures, approaching the original pristine conditions.

Will summer flows in watercourses be a half lower by 2060?

The increase in potential evapotranspiration due to warming is quite often used as an indicator of ongoing and predicted changes in the hydrological balance. However, without assessing its effect in basins with different precipitation regimes, it is not correct to consider a change in potential evapo-transpiration as an increase in actual evapotranspiration or a decrease in runoff.

„Water Centre“

The research project of the Technology Agency of the Czech Republic SS02030027 „Water systems and water management in the Czech Republic in conditions of climate change“, whose guarantor is the Ministry of the Environment, tries to answer the question of whether we will continue to have enough quality water. Climate change and the associated drought, as well as human behaviour and demands threaten water, and solutions must be sought for the immediate future.

Application for the parametrization and automatic running of the HEC-HMS rainfall-runoff model

This article presents an application developed in the Czech Hydrometeorological Institute (CHMI) to support hydrologic modelling using the HEC-HMS model as the primary used rainfall-runoff model. The application enables group editing of selected parameters of the model schematiza-tion, automatic running of simulations, display of selected simulation results, and communication of the HEC-HMS
model with GIS and other selected models, e.g., HEC-RAS or MIKE 11. The application is designed to use only freeware and open source libraries and is capable of operating under both Windows OS and UNIX/Linux OS. This article briefly describes the current state of the application devel-opment and its functionality, even for readers without major IT background. Further development is outlined in the last part of the article. Further development of the application is aimed at higher support for hydraulic modelling at the level of communication between the HEC-HMS and HEC-RAS models, as well as at the level of automatic parameterization and launching of the HEC-RAS model and its communication with other tools, e.g. hydraulic model MIKE 11 or GIS post-processing of the results.

Atmospheric deposition as a possible source of surface water pollution (Results of the project, part 2. – polycyclic aromatic hydrocarbons)

From October 2020 to September 2021, in two forest micro-catchments in the Czech Republic, the quality of wet atmospheric deposition (bulk and throughfall) was monitored simultaneously with the surface water quality in the local watercourse, humus, and the moss species Pleurozium schreberi. An evaluation is presented of the 15 polycyclic aromatic hydrocarbons (PAHs) burden of the above-mentioned matrices. The first site was chosen in the Beskid Mountains in the Moravian-Silesian region, in the cadastre of the village of Bystřice in the upper basin of the Suchý stream (altitude 590 to 835 m a.s.l.). This area is affected by industrial activities. The second reference site was chosen in the Bohemian-Moravian Highlands near Košetice observatory (altitude 520 m a.s.l.).

Development of pond locations in the Polabí lowland since the mid-19th century – part 2 – Poděbrady region

This article presents the results of research on landscape changes in the Poděbrady region as part of the Polabí lowland, where there have been significant changes in the location of ponds. The area of all types of ponds (according to stability) makes up 3.17 % of the Poděbrady region. Ac-cording to their occurrence in the area in 1836/1852–2022, the ponds (or their parts) were divided into disappeared, continuous, and new. Disap-peared ponds have the largest representation – about 60 % of the total pond area according to stability. They are followed by continuous ponds, with the minimum area represented by new ponds. The historical or (more precisely) disappeared ponds were more robust than the present ones, i.e., they had a larger average size. Analyses show that almost three-quarters of the disappeared ponds have been replaced by arable land.

Fundamental revision of the Urban Waste Water Treatment Directive provokes conflicting reactions from European Union member states

Council Directive 91/271/EEC of 21st May 1991, the Urban Waste Water Treatment Directive (UWWTD), entered into force 32 years ago, which is a respectable age for a legal regulation. Since then, through the consistent implementation of its requirements, good results in water protection have been achieved in practice. Between 1990 and 2014, there was a reduction in the amount of pollutants in treated and discharged urban waste water for organic pollution expressed as BOD5 by 61 %, for total nitrogen by 32 %, and for total phosphorus by 44 %. The extensive support pro-vided to cities and municipalities from EU financial instruments as well as from national sources and the relatively strict application of sanctions have led, according to data published by the European Commission (EC), to the fact that currently 98 % of waste water in the EU is effectively collected and removed of and 92 % properly treated. Until now, the Directive’s requirements have primarily focused on centralized systems for the collection, removal, and treatment of waste water in agglomerations producing loads at the level of 2,000 population equivalent (PE) and more.

Juvenile fish assemblages – appropriate tool for monitoring of the ecological status

Aquatic organisms have a very good ability to reflect the conditions of the environment they live in and, therefore, they are often used to assess the ecological status of that particular environment. of juvenile fish assemblages (0+) represent an appropriate tool for monitoring the ecological status of watercourses as they show a very rapid response to changes in environmental conditions. The goal of this study was to assess assemblages of juvenile fish (0+) at 22 sites across the Czech Republic between 2019 and 2021.

Development of pond locations in the Polabí lowland since the mid-19th century – part 1 – Pardubice region

This article focuses on mapping the development of the lowland landscape over the last 180 years, related to pressures to use lowland areas for economic purposes, including transformation of wetland habitats (specifically ponds) into arable land.  The Polabí lowland was chosen as the study area because it is currently affected by a lack of water and there is an occurrence of seasonal drying up of small watercourses. This issue will probably be of greater significance in the future, particularly in the context of the expected continued extreme climatic phenomena. Within the Polabí lowland, the results from the Pardubice region (where the biggest change in pond locations occur) are presented here. The area of all types of ponds (according to their stability) makes up 6.83 % of the study area. According to their occurrence from the Second Military Mapping (1836–1852) up to 2022, the ponds were divided into disappeared, continuous, and new. Disappeared ponds have the largest representation – about two-thirds of the total pond area according to stability. They are followed by continuous ponds, and the smallest area is represented by new ponds. The historical, or more precisely, disappeared ponds were more robust than the present ones, i.e., they had a larger average size. Analyses show that almost half of the disappeared ponds have been replaced by arable land.

Optimization network model of water management systems

The paper describes software aimed at analysing water management infrastructure and identifying critical points for water supply and assessing possible measures aimed at optimising the water supply function of the water management system. The computational procedures integrate the evaluation of the hydrological characteristics of the area, the parameters of the water management and water supply systems and the water supply requirements. The solution uses graph theory and network flow optimization (out-of-kilter algorithm is applied). The program is implemented as a PC application and equipped with a user interface.

Technical Heritage of the Elbe-Vltava Waterway

From 8th November 2022 to 31st January 2023, an exhibition entitled “Technical Heritage of the Elbe-Vltava Waterway” took place in the atrium of the Faculty of Civil Engineering of the Czech Technical University in Prague (CTU). The exhibition included exhibition panels, an interactive model of a weir lock, a video projection screen, and a stand with a web application www.lvvc.cz. The exhibition mapped the history and development of this 324 km waterway since the beginning of the 19th century, and it is expected to continue as a travelling exhibition.

Landscape changes in selected locations of the Polabí lowlands with a focus on wetlands

This article presents three typologically different sites from Polabí where large-scale wetland sites were located in the past, including ponds. These sites were chosen in order to present disappeared floodplain meadows, disappeared “field” wetlands, disappeared ponds or pond systems, and, simultaneously, to present sites where wetland habitats have been at least partially restored. The main aim was to present easily accessible archival maps, on the basis of which it is possible to assess the spatio-temporal dynamics of wetland habitats in the places of disappeared wetlands with regard to their possible restoration.

Multi-Criteria Analysis of the Dyje basin

This article deals with applications of the specific method of multicriteria analysis (MCA) and its use in the identification of areas within the Czech Republic where adaptation measures to the consequences of climate change would be most effective. MCA was chosen due to its comprehensive approach and the simplicity of working with available data in the Czech Republic. The first MCA have already been applied in the Pilsen and Pardubice Regions within the framework of the creation of the strategic document Regional Strategy of Adaptation Measures (Regionální strategie adaptačních opatření, ReSAO), whose aim was to assess the vulnerability of the entire area of these regions. The results from both strategies are expedient from the point of view of drafting adaptation measures, and it was therefore decided to use MCA as part of a larger project in the Dyje basin. In the first phase, the implemented analyses were evaluated to improve MCA for the studied area. In the second phase, MCA was applied to the area of agricultural land. Several thematic indicators were evaluated, namely surface drainage, land use, erosion risk, and occurrence of erosion events. The aim was to focus on IV order basins, in which the priority of implementing measures on agricultural land is the highest. The result was a list of IV order basins with a partial and summary assessment of problems within the total studied area of the Dyje basin.

Agroforestry and its effect on the complex of hydropedological properties of the soil

The aim of this article is to evaluate landscape retention capacity based on the use of soil protection technology at the chosen site and to compare selected hydropedological characteristics in the context of land management. Therefore, broken and intact soil samples are taken regularly and laboratory analyses are carried out. The chosen site is located in the Šardice cadastral area, Hodonín district, South Moravian region. At the chosen site it is possible to consider grass strips with one or more rows of trees as a possible agroforestry system, where temperature and humidity are measured continuously by TOMST TMS-4 moisture sensors. The results show that the way land is used and cultivated has an impact on hydropedological properties of the land. We can influence them both positively and negatively.

Planned restoration of aquatic ecosystems in Prague 4

Prague 4 district in accordance with the National Action Plan for Adaptation to Climate Change [1], Concept for Protection from the Effects of Drought of the Czech Republic [2], Strategy for Adaptation of the Capital City of Prague to Climate Change [3] and Methodology for Rainwater Management in the City [4, 5], similarly to other progressive-minded parts of Prague, is preparing investment actions to support and strengthen green-blue infrastructure in the city. One of the most visible measures with truly demonstrable effects on the support of biodiversity and water retention in the landscape is the restoration of aquatic ecosystems. In the case of the capital city of Prague and its most populous district of Prague 4, these are mainly the restoration of canalized (straightened or piped) streams, or desilting, strengthening or comprehensive restoration of ponds and small water reservoirs in a highly urbanized landscape. A specific area is newly emerging bodies of water in places where water naturally tends to be retained after longer periods of rainfall and the area thus cannot be used for any other purpose, or even in places where there was no body of water before (although here in the narrower sense of the word it is not restoration). For such areas created by human intervention in order to strengthen the diversity of aquatic and wetland vegetation, the name artificial aquatic biotope has been adopted. Let us have a look at the differences and specific pitfalls of individual restoration using three specific examples.

Historic floods on Rakovnický stream

This year, TGM WRI is planning to publish a book by Kašpárek, Elleder, Šírová, Dragoun, and Kašpárek Jr., dedicated to floods in the Rakovnický stream basin. It is primarily focused on the occurrence of floods before the start of instrumental observation, that is before 1898. Its purpose is to maximally expand knowledge about the frequency, seasonality, and most significant flood cases, their causes, extent, impact, and damage over the last 500 years.

Radioactive indicators in surface waters of the Ploučnice river basin

The Czech Hydrometeorological Institute (CHMI) is engaged in systematic monitoring and evaluation of radiological indicators in surface waters. The article describes changes in the values of radiological indicators in surface waters in the time series from 1967 to the present. The evolution of total volume alpha and beta activity, uranium concentration, and radium activity (226Ra) is described on characteristic profiles in the area of uranium-containing raw materials mining, in the vicinity of Stráž pod Ralskem, where the mining of radioactive raw materials has already been suppressed. The Ploučnice river flows through this mining area and flows into the Elbe river in Děčín near the Hřensko border crossing, where activities of radiological indicators are also monitored and documented. Following the cessation of uranium mining at the Stráž pod Ralskem deposit, uranium concentrations dropped by two orders of magnitude, and surface waters on the Ploučnice – Mimoň profile have been classified as Class I – unpolluted water for the last five years. The values of Kendall’s correlation coefficient τ for the profiles evaluated on the selected profiles during the mining period are characterized by an increasing trend (+0.7) for the indicator of total volume beta activity; after the end of mining, a decreasing trend is indicated (-0.5).

Impact of weir construction at locality Abovce (Slovakia) on groundwater levels – a case study from Slaná river basin

The construction of weirs on rivers affects the dynamics of groundwater levels. The weir built on the river Slaná in the year 2010 between the village of Abovce and Chanava brought the opportunity to study such impact due to preexisting groundwater monitoring wells of the Slovak Hydrometeorological Institute. to verify the impact of the constructed weir on groundwater dynamics in the area, records of weekly data were used ranging from 1986 to 2018. In addition, the spatial range of influenced areas was carried out using geographical information systems, and spatial interpolation techniques were used. The results showed that immediately after the construction of the weir, the groundwater level rose significantly.

Potential of areas protected for surface water storage to mitigate the impacts of climate change on drinking water supply

In the Czech Republic, areas morphologically, geologically and hydrologically suitable for surface water storage to mitigate the adverse effects of floods and droughts are defined through the General Plan for Surface Water Accu-mulation Areas. In the context of climate change, these locations create potential for possible adaptation measures. This article describes the assessment of the potential of selected sites for water supply under climate change condi-tions by means of hydrological and water balance modelling.

Small headwater catchments – spatial delimitation and their classification in terms of runoff risks

This article presents an aerial delineation of small headwater catchments up to 5 km2 in the Czech Republic. The aim was not only to present the delineation of these catchments, but also their categorization in terms of the characteristics affecting the formation of direct runoff. Direct runoff caused by torrential rainfall is a very dynamic process of episodic nature and has a major impact specifically in small catchments. The delineation of small headwater catchments, where the aforementioned processes take place, can complement the standard hierarchical classification of basins in the Czech Republic. These basins make up 80 % of the Czech Republic.

Modelling flow distribution in inlet galleries

The main objective of the article was to optimize the facilities used to distribute flows in inlet galleries, which are used not only in water treatment plants, but also in wastewater treatment plants (WWTP). While working in the field of WWTP, it was found that there are no optimized facilities in the Czech Republic or globally for uniform distribution of flows to any number of inlet branches into reservoirs of the same flow rate.  Currently, in most unregulated facilities, there are significant differences between the various inlet branches to the reservoirs. In regulated facilities, the outlets must be regulated at each change in flow rate and, for changes in the number of inlets to the reservoir (e.g., due to reservoir shutdown), each outlet must be manually adjusted (e.g., using a sluice gate) so that all inlets to reservoirs have the same flow rate. In more modern cases, the sluice is equipped with an electric motor for changing the position and a probe sensing the level. The central unit then calculates the flow rate in the individual reservoir inlets and adjusts the position of the sluice gates so that the same flow rate is achieved everywhere. The objective of the research was to optimize the distribution facility so that the inlets to the reservoirs reach similar values for the flow rate when both the inflow to the distribution facility and the number of inlet branches to the reservoirs are changed, without significant regulation at the distribution facility. In order to make the research easily applicable to as many distribution facility as possible, the most commonly used flow distribution facilities (fountain spillway, flume with outlets fitted with a sluice gate and probe for level monitoring, etc.) were selected to address the issue. Different flow conditions were simulated on the selected facilities (in different variants and shapes); after their analysis the facilities were optimized in order to achieve the most similar flows at the inlets to the individual reservoirs.

Interview with Jaroslav Pollert, professor at the Faculty of Civil Engineering at CTU and a successful Czechoslovak representative in canoeing

An interview with Jaroslav Pollert, professor of the Faculty of Civil Engineering at CTU and a successful Czechoslovak representative in canoeing, about his work as part of the Executive Committee of the International Canoeing Federation (ICF), the Czechoslovak and later the Czech Olympic Committee, about his professional career focused on the hydrodynamics of dispersion systems including, among other things, designing channels for water slalom and about his view on water management studies at Czech universities.