Projects of Internal Grant Agency of CTU

Reconstruction of water supply systems

Duration: 2007
Contact person: Ing. Filip Horký

Water is the basis of life, so supplying people with drinking water is one of the topics of our interest. Because of this fact, sustainable development is necessary in order to ensure the quality and reliability of drinking water supply. Reliability depends on many factors: from the characteristics of pipe material used and discipline during underground laying to consequential servicing and well-timed and suitable reconstruction. The project is focused on a review of possible reconstruction methods of water supply systems (usage possibilities, positives and negatives and economic comparison). Special attention will be devoted to the application of trenchless technologies, which is currently a domain development trend. The project will further deal with the methodological process of failure recovery and the methodology of recognition and evaluation of the current state of the system in relation to mathematical distribution networks modeling and failure simulation.

Terms of application of rainfall-runoff simulation models in field of urban drainage

Duration: 2007
Contact person: Ing. Lukáš Novák

In the Czech Republic, rainfall-runoff simulation tools have been used for solving problems of urban drainage for more than 15 years. They are an important decision support tool for increasing efficient operation of urban drainage, efficient capital assets for reconstruction and development of these systems and for decreasing negative effects on environment. Costs of urban water management and the penalties of its mismanagement are so high that computer models used for its design and analyzing ought to be solidly reliable.
A number of Czech governmental standards recommend the application of simulation tools, but they don’t specify in detail which requirements should models fulfil, e.g. aspects of data requirements or descriptions of hydrological and hydraulics processes.
The proposed project will summarise recommendations for quantity aspects of rainfall-runoff modelling in urban catchments used in other regions over the world. Based on this information, recommendations for the solution of these problems in the Czech Republic will be suggested.

Comparison of separation efficiency of new and conventional types of CSO devices

Duration: 2007
Contact person: Ing. Petr Srníček

Combined sewer overflow chambers (CSO) are an indispensable component of unitary sewer systems. The main function of CSOs is to safeguard hydraulic capacity of sewer network and to allow overflow of excess diluted wastewater into receiving waters. CSOs constitute a significant source of pollution of receiving waters (organic matter, suspended solids, heavy metals, visual pollution etc.) Traditional design of CSO chambers is based on hydraulic balance (dilution ratio). However, modern trends in urban drainage demand some kind of treatment of CSO, at least removal of gross solids. The objective of this project is to evaluate the efficiency of separation of suspended solids in various types of CSO chambers and compare them. The project will combine mathematical simulation of CSOs with field research.

Management of Water Supply Operations - Analyse to Loss

Duration: 2006
Contact person: Ing. Renata Veselá

Water losses indicate the amount of water leaked out of the water distribution system, not efficiently used and the amount of water taken but not discovered and not registered by the operator. Loss monitoring is one of the basic obligations of operators. Their size points to technical states and network operations, and at the same time is decisive for returns on future investment. Loss reports have recently recorded several changes. Values that describe the amount of unique leakage are continuously more often being used with traditional percentage data on losses related to the overall volume of supplied water. These methods try to cover various types of plants.

Incipient motion of cohesive sediment

Duration: 2006
Contact person: Ing. Jakub Jirák

The presence of the sewer sediment is unwished phenomenon in both the manner nature protection and the sewer network maintenance. On the one hand the presence of the sewer sediment leads to decrease in flow capacity on the other hand the sewer sediment behaves like an accumulator of toxic pollutants (e.g. heavy metals, organic pollution). The effort to understand the sediment transport has been mainly focused on natural rivers and streams in the past. However, by contrast to natural streams the sewer sediment is often cohesive. Therefore, the mechanisms of occurrence in natural streams are not fully applicable in sewer management. Thus, for the better understanding of the sediment transport in sewer system, the knowledge of sediment cohesion is essential. It can be obtained from shear stress produced by water flowing over the sediment bed. The time synchronization of hydraulic and turbulence measurement in inner region together with video recording of bed-load movement using CCD camera is the way how to define objectively the sediment cohesion.

Factors of Heavy Metals Mobility in Small Urban Streams

Duration: 2003
Contact person: Mgr. Jana Nábělková

The project aims at the research of heavy metals mobility in the stream ecosystem. Heavy metals belong to the most dangerous contaminants getting to watercourses in urban areas. Most of them are strongly toxic for fishes and other aquatic organisms and via the food chain they get to higher trophic levels (birds and human) and have toxic, carcinogenic and teratogenic effects. The toxic impact depends on the form of incidence of the metal; they are toxic mainly as dissolved ions. Although heavy metals tend to bind into a solid phase (bottom sediment), where they are relatively unavailable for organisms, their behaviour and possibility of releasing to the water phase under changing conditions (pH, hardness, redox potential...) haven't been quite clarified till this time.

Distribution of heavy metal between the water and solid phase is described by Partition (Distribution) coefficient (Kd). Kd is the relation between metal concentration in the solid phase and concentration in water under equilibrium. Kd value changes with changing conditions, so it makes it possible to observe mobility of heavy metals. The project deals with actual problems that have not exam in the Czech republic yet and it is in agreement with ideas of the EU about achievement of good ecological status of watercourses of member countries till 2015.

The project objectives include:

  • Establishment of equilibrium time during distribution of a metal between the solid phase and water solution
  • Determination of Kd dependence on various conditions of water environment for chosen metals (Cu, Zn, Pb)
  • Verification of the possibility to generalize the obtained results for other heavy metals
  • Application and verification of experimental results in real conditions of small urban streams

Ecological risk assessment of urban drainage in a small stream

Duration: 2002
Contact person: Mgr. Gabriela Šťastná

The urban impact in a small stream can show itself in various ways. In my project, I would like to deal with the urban drainage impact into the stream water quality and above all with quality and quantity of makrozoobenthos living in the stream. Currently the stream biological evaluation is underrated, however the organisms living in the water sensitively reflect the change in the evironmental quality over a long time period. The urban drainage directly influences stream water quality with its combined and separate sewer systems outfall.
Storm sewer systems at first cause hydraulic problems, reverberating on the stream, therefore morphology changes and thus changes the water biotop for different kinds of organisms. The combined sewer systems make the biggest risk because of pollution. It brings in (heavy metals, organic pollutant etc.).These pollutants can partially remain solute in the water or sorbs to the sediment. Both of these environments provide living conditions to water organisms and by the way of the food web are accumulated in their bodies from which we can observe environmental changes.


  • stream biological condition evaluation by using predictive system PERLA
  • Phabsim program apllication
  • organisms ressetlememt time assessment
  • water invertebrates heavy metals contain

Assessment of stream ecological status in urban watersheds

Duration: 2002
Contact person: RNDr. Dana Komínková, PhD.

The framework of development of the environmental science in Czech Republic focuses on reduction of negative impact of human activities on the environment. The project addresses on monitoring of changes in quality of rivers and consequently on protection of rivers agains pollution by urban watershed. The background of risk assessment methodology for discharge of pollution from combine and storm sewer during rain will be developed. Proposal of complex methodology will be in agreement with requirements of Directive 2000/60/EU. The Directive required that rivers and streams have to reach minimally good water status. This means not only good chemical status, but also good ecological status. The ecological status describes structure and function quality of ecosystems, which is connected with the surface water. It is necessary to assess rivers as a complex of chemical, biological, hydrological and geomorphological segments.


  • Development of methodology of ecological status assessment in urban watershed. Emphasis will be lay on effect of pollutants with cumulative effect (heavy metals) and in this initial part we will focus on toxicological impact on biota.
  • The background of database about ecological status of small Prague's streams will be developed and the reference stream will be identified.

Modelling of Unsteady Turbulent Flow Characteristics in Circular Tube

Duration: 2001
Contact person: Ing. Vojtěch Bareš

Wastewater flow in urban drainage systems is governed by many specific factors. Water includes many solid particles, and both cross-section area and pipe material is very often varying. Stationary flow with free surface prevails in dry weather periods, while during rain events flow changes to transient and can even develop into pressure-mode flow. Transport of bed sediments occurs usually during rain events when the flow is unsteady. Flood waves in sewer systems have different shapes, so we can consider effects on hydraulic characteristics and impacts to transport of sewer solids both deposited and suspended.
The goal of an experiment was to analyse hydraulic characteristics such as instantaneous longitudinal and vertical velocities, turbulent intensities and shear stresses in circular pipe with unsteady turbulent free-surface flow for both rising and falling branch of hydrograph. Different shapes of hydrographs were analysed.
We can found some experimental studies made in the last decade focused on unsteady free-surface flow like Tu, Graf (1992) or Nezu, Nakagawa (1995). These authors used for experiments specific hydraulic condition, mostly, rectangular cross-section flumes. Methods of measuring of the velocities and turbulence were also different (micropropellers, 2D LDA).

Nutrients management in urban drainage

Duration: 1999
Contact person: Ing. David Stránský, Ph.D.

The suitable definition of space scales of investigated systems is one of the most important questions within the water management. The approach adopted was to identify major (not only nutrient) pollution problems in a regional scale and to determine the cause-effect relationship in a local scale. The regional scale solution methodology was based on combination of monitoring and modelling.
The analysis of the present state of the Litavka River has identified concentrations of total phosphorus above an acceptable threshold. Sensitivity analysis has been used for discovery of major cause - confluence with Pribramsky creek. High concentrations of total phosphorus in Pribramsky creek are directly caused by urban drainage of town Pribram.
Attention was focused on town of Pribram in the next (local) level of investigation, which included description of phosphorus budget within the entire urbanized area.
Evaluation of urban drainage behaviour has been based on 30 hours monitoring campaign. The measuring profiles has been chosen in order to evaluate the effect of town on Pribramsky creek and Litavka River. It allows to identify processes dynamics as well as the phosphorus budget within the catchment. More then 90 samples have been taken in total. Evaluation of urban drainage behaviour has been based on 30 hours monitoring campaign. The measuring profiles has been chosen in order to evaluate the effect of town on Pribramsky creek and Litavka River. It allows to identify processes dynamics as well as the phosphorus budget within the catchment.

Using Mathematical and Physical Modelling for CSO

Duration: 1999
Contact person: Ing. Jaroslav Pollert, Ph.D.

During the last 30 years, a number of devices have been developed for dynamic separation of settleable solids in wastewaters. Initially, these separators were used for control of Combined Sewer Overflow (CSO) pollution by retaining the bulk of solids in the underflow, directed to the sewage treatment plant (STP), and allowing combined sewage with reduced pollutant loads to overflow from the sewer system.
Water flow in sewers is modeled numerically in 3D in real time. Special problems are objects in sewer systems and this model FLUENT was used for simulation CSO (Combined Sewer Outlet).
Simulations show several types of CSO and compare them with reality or physical model. First was solved real problem of CSO in Prague 6, Evropská Street, which had many operational problems.
The main aim of investigations was concentrated into functional dependence between inlet, outlet and overflow. Simulation was carried out with new solver prepared for free surface. The most important was finding of water levels in CSO. Boundary conditions of the whole simulated objects were about 50 m in length and 5 m in high. Inflow tube was 3 m
Results from mathematical modeling were verified with hydraulics conditions in CSO Evropská, which were measured for longer period before. Simulation was done mainly for inflow higher then was measured so it is the only way how to detect behavior of CSO.
Water flow patterns in sewers were modeled numerically in 3D as a time dependent (4D). For simulations was used program FLUENT v5.4. Simulations have been carried out for several different inflows.
Results from mathematical modeling were verified with real hydraulics conditions in CSO Evropská, which were measured for longer period before. Simulation was concentrated mainly for inflow higher then measured and this way went to detection of CSO behavior.
Another problem, which has been simulated, was CSO in Prague 10 Hostivař. Problem was similar as previous one, but in this simulation were also used injection techniques. This model gives us information about separation efficiency.
The last simulation was the vortex separator. The models we want to compare with other CSOs previously modeled and confront their separation efficiency.