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Rainwater harvesting systems (RWHs) are identified as an alternative technology that is important for sustainable stormwater management through reuse, conservation, and reduce runoff. In recent years there has been a growth of studies on the effectiveness of RWHs. However, analyses of the system performance based on the site specific conditions are still limited. The aim of the study was to assess of the potential for rainwater reuse (householder's interest) and reduction of roof runoff by RWHs (an environment's perspective) assumed in a singlefamily building. Two performance indicators have been calculated i.e. water saving potential (WSE) and overall efficiency (OE). Four realistic scenarios (S1-S4) and three main non-potable water requirements were defined. The results of the study showed that WSE and OE varied depending on the type and size of the tank, the economic purpose, and the amount and irregularity of precipitation. The potential for the use of water stored in above-ground tanks for plant watering ranged from 62 to 82%. Underground reservoirs, with a larger capacity, were able to cover water requirements for this purpose up to 100%. However, the OE of tanks receiving runoff from the entire roof area were at low levels. Values of OE ranged from 3.7 to 6.8%, from 5.5 to 9.2%, and from 42.9 to 71.0%, for above-ground (S1 and S2) and underground (S3) and (S4) tanks, respectively. The results of the study may be useful for planning domestic rainwater harvesting systems and for comparison with practices in other countries. [ABSTRACT FROM AUTHOR]

The paper presents the evaluation of the relation between meteorological elements and air pollutants’ concentrations. The analysis includes daily concentrations of pollutants and variation of meteorological elements such as wind speed, air temperature and relative humidity, precipitation and total radiation at four monitoring stations located in the province of Lower Silesia in individual months of the winter half-year (November–April, according to hydrological year classification) of 2005–2009. Data on air quality and meteorological elements came from the results of research conducted in the automatic net of air pollution monitoring conducted in the range of the State Environment Monitoring. The effect of meteorological elements on analysed pollutant concentration was determined using the correlation and regression analysis at significance level α < 0.05. The occurrence of maximum concentration of NO, NO2, NOX, SO2 and PM10 occurred in the coldest months during winter season (January, February and December) confirmed the strong influence of “low emission” on air quality. Among the meteorological factors assessed wind speed was most often selected component in step wise regression procedure, then air temperature, less air relative humidity and solar radiation. In the case of a larger number of variables describing the pollution in the atmosphere, in all analyzed winter seasons the most common set of meteorological elements were wind speed and air temperature.

The intensive development of urban areas results in the sealing of increasingly large areas. In such conditions the existing sewer systems are quite often unable to simultaneously collect sewage along with the additional volume of rainwater. These systems require control of the hydraulic parameters in order to recognize the hydraulic conditions that occur in different operational states. Nowadays, such control may be exercised through the use of models that are capable of prediction as a result of the process of learning from a database of historical events. The study presents the possibilities of using Artificial Neural Networks (ANNs) for the analyses of the time series of waste-water depth and flows in a combined sewer system. The measurement campaign organized in Wrocław (Poland) enabled obtaining data on the hydraulic parameters of the flow of sewage in the sewer systems, and rainfall of various characteristics. The test results demonstrate that algorithms of the MLP (Multi-Layered Perceptron) Artificial Neural Network may be implemented to predict the flow rate in the system. The method presented in the paper may be applied to the daily operation of sewer systems to predict transient flows. The obtained results demonstrate a good and very good accuracy of prediction model.

Modern engineering workshop of designing and modelling complex drainage systems is based on hydrodynamic modelling and has a probabilistic character. Its practical application requires a change regarding rainfall models accepted at the input. Previously used artificial rainfall models of simplified form, e.g. block precipitation or Euler's type II model rainfall are no longer sufficient. It is noticeable that urgent clarification is needed as regards the methodology of standardized rainfall hyetographs that would take into consideration the specifics of local storm rainfall temporal dynamics. The aim of the paper is to present a proposal for innovative methodology for determining standardized rainfall hyetographs, based on statistical processing of the collection of actual local precipitation characteristics. Proposed methodology is based on the classification of standardized rainfall hyetographs with the use of cluster analysis. Its application is presented on the example of selected rain gauges localized in Poland. Synthetic rainfall hyetographs achieved as a final result may be used for hydrodynamic modelling of sewerage systems, including probabilistic detection of necessary capacity of retention reservoirs.

At present, stormwater management is one of the key issues in urban policy. This is due to the increasing urbanisation, climate change, the growing threat of extreme (weather) events and the need to protect water resources. Legislation plays an essential role in the process of project planning and implementation. The recognition of opportunities and barriers contained in these regulations forms the basis for action by the central government, local authorities and investors. The article aims to analyse legal provisions, administrative decisions and factual circumstances that provide the foundation of administrative court rulings in Poland and regard the legal possibilities of rainwater management in urban areas. The adopted research method allows for/includes the author's interpretation and formulation of de lege ferenda conclusions. The results of analyses of both European and national legislation and case law indicate that there is a problem with the interpretation of existing legislation and the lack of legal definitions of basic equipment and solutions in the field of water law, for instance. Such legal circumstances make it difficult to make the required legal decisions, and have a negative impact on the timing of implementation and number of these muchneeded projects. [ABSTRACT FROM AUTHOR]

Nowadays green roofs play a key role in alleviating the negative effects of urbanization. Despite investors awareness of the advantages of green roofs, there are still some barriers that hinder investments on a large scale. As a result a financial and non-financial incentives are implemented. The review presented in this paper allowed to identify the most popular initiatives and to formulate recommendations for creating incentive supporting implementation of green roofs in urban areas. [ABSTRACT FROM AUTHOR]

Green roofs as solutions that can offer varying levels of stormwater management are the topic of current interest. In order to use this form of reconstructing retention capacity, it is important to understand the influence of meteorological conditions on the functioning of living roofs. The study presents the results of research, using of the ANOVA variance analysis method, on retention performance (i.e. volumetric control) and detention (temporal delay run‐off) carried out in the years 2009–2014. The results indicate that the green roof can effectively retain rainfall and delay the initiation of run‐off from the rainfall events included in the analysis. Understanding the hydrological performance of green roofs in different local meteorological conditions is key to the successful implementation and development of sustainable practices to control run‐off in urban areas. [ABSTRACT FROM AUTHOR]

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Accurate dimensioning of drainage systems requires assumption of reliable design rainfall intensities as a function of its duration and probability of exceeding according to PN-EN 752:2017. Design rainfall intensities are determined by application of an adequate rainfall model that is based on statistical analysis of local precipitation time series recorded at high time resolution and covering a period of last 30 years minimum. Beside application of the obsolete Błaszczyk's formula, the Bogdanowicz-Stachý's probabilistic maximum precipitation model based on 1960-1990 rainfall records from 20 rain gauges (Institute of Meteorology and Water Management) becomes increasingly popular in Poland. However, this model does not support full coverage of the country and is based on the discontinuous regionalization. Evolving climate conditions demand validation of the model for use throughout the country. This paper presents results of verification of the actual values of rainfall intensities derived from 30-year time series from the period of 1986-2015 for given probabilities of exceeding, in comparison to the estimates delivered by the Bogdanowicz-Stachý's model. The conducted analysis undermines legitimacy of the simple regionalization concept for precipitation in Poland. Moreover, rainfall intensity values calculated by Bogdanowicz-Stachý's model for probabilities of p = 100% and p = 50% are mostly understated and for p = 20% and p = 10% are overstated in comparison to actuals (1986-2015). The results of the research confirm the need to replace Bogdanowicz-Stachý's model with "new generation" local maximum precipitation models developed as part of the PANDa (the Polish Atlas of Rainfall Intensity) atlas, not only to obtain full coverage of the country, but also to make the values of rainfall intensities reliable for design of drainage systems. [ABSTRACT FROM AUTHOR]

Despite serious questions to the theoretical fundamentals as well as the limited and outdated precipitation data, the Blaszczyk's formula for the design rainfall intensity is still in use for sizing drainage systems in Poland. The assumption of close functional dependence between the average annual precipitation depth and maximum rainfall intensities is the basis for the formula (IDF-type, i.e. intensity-duration-frequency). The assumption was verified against the actual values of maximum rainfall intensity, derived for the purpose of development and implementation of the Polish Atlas of Rainfall Intensity (PANDa rainfall model). The actual maximum rainfall intensities for different duration periods were retrieved from the precipitation records obtained from the nation-wide network of 100 rain gauges of the Polish Institute of Meteorology and Water Management (IMGWPIB) for the period of 1986-2015. These values were compared to the corresponding Blaszczyk formula's estimates. Based on the results, the basic assumption of the formula was questioned, namely that the maximum rainfall intensity values are not correlated with the normal annual precipitation depth. A clear tendency for the rainfall intensity values to be underestimated by the Blaszczyk's formula was observed. It was demonstrated that the mean relative error between the actual and estimated rainfall intensities was 33%. Even for the original hydrological Warsaw conditions, the Blaszczyk formula proved unacceptable due to significant underestimation of current rainfall intensities. In view of the findings, a complete elimination of the formula from drainage system engineering in Poland is recommended. [ABSTRACT FROM AUTHOR]

Granulometric composition of suspensions contained in filter backwash water affects filter treatment technology selection. The paper describes results of granulometric composition studies on filter backwash water suspensions collected from 46 groundwater treatment plants. An original, modified Avrami equation was proposed to interpret the results of studies on granulometric composition determined by the use of laser diffractometer. The equation enabled identification of mechanism in which suspensions are formed in filter beds applied for groundwater iron and manganese removal process. The research showed that iron and manganese concentration growth in treated groundwater correlated with increase in the percentage of suspended particles with small equivalent diameter and in changeability range of particle equivalent diameters in backwash effluent. At low contents of iron and manganese compounds in treated water polydisperse suspensions were formed, characterized by narrower changeability range of particle equivalent diameters. [ABSTRACT FROM AUTHOR]

The paper discusses the problem of increasing population and associated water usage in cities. With this in mind, an attempt was made to use Water Footprint (WFTP) indicator as a tool facilitating decision-making process in order to improve water management in urban areas. A need for preparing water balance analysis of cities was demonstrated and examples of indicators so far developed given, addressing that need. Furthermore, a new term of Urban WFTP indicator for urban areas was introduced and its justification. Methodological basis and examples of its calculation were provided. Finally, purposefulness of knowledge dissemination was demonstrated regarding urban water balance modeling as well as developing long-term modernization strategies for water supply and sewage systems. This will also enable an increase in water resource management rationalization factor in urban areas, but also will support development and implementation of new technologies and alternative solutions as regards natural water cycle. [ABSTRACT FROM AUTHOR]