The influence of stoppages on productivity during construction of water supply and sewage systems

The influence of stoppages on productivity during construction of water supply and sewage system

Management of Alterations to Project Documentation – a Case Study of Water Supply and Sewerage Works

Background. The implementation of alterations to project documentation is the modification of certain solutions, assumptions or requirements. It mostly involves the verification or the specification of project documentation with regard to the actual conditions of execution or the investor’s expectations. The management of alterations in a construction project is aimed at predicting any negative consequences caused by changes in the investment process and their prevention or mitigation. Previous experience indicates that alterations to project documentation introduced during the execution of the work are widespread. They contribute to loss of time and increase in the cost of the project. For this reason, it is necessary to develop and implement an effective model for the management of such alterations.Research aims. The project manager, before construction, should be aware of any alterations to the project documentation that may have occurred during its execution, and their possible consequences. The aim of the study is to identify the causes, the structure and the consequences of alterations to project documentation with regard to water supply and sewerage construction.Methodology. The basis of the research and analyses constitute a detailed review of documentation compiled from eight projects in water supply and sewerage. Among the documents concerned, the “Records of Necessity” and “Records of Negotiations” were especially valuable for conducting the analysis.Key findings. The research conducted indicated the crucial role of the investor in the process of managing alterations to project documentation. The research revealed that proper preparation of the investment process, i.e. recruiting the best designers to prepare the project documentation, tracking changes in the nearer and farther surroundings, may significantly contribute to reducing or even eliminating many alterations to project documentation during the execution of the work

ECOLOGICAL RISK ASSESSMENT IN THE REGULATED WATERCOURSES

Ecological risk has not been identified well enough for the designers and contractors to take any actions for its limitation. It results from the lack of the basis formed to assess its level objectively. The aim of this study was to determine the standards useful in the evaluation of the ecological risk for aquatic plants in rivers, where it is planned to conduct regulatory works. The basis for the analysis were the results of the study performed in 2008–2014 in unmodified and transformed lowland watercourses in Lower Silesia. 41 study sections were analysed in 11 watercourses. 30 sections were located in regulated watercourses, while 11 were in unmodified streams. The research included vascular aquatic plants identification and the degree of the bottom coverage by these plants. As a result of regulatory works qualitative and quantitative changes in aquatic plants communities were observed. The analysis of these changes concerning the range and conditions of works conduction enabled assigning measures to the factors of the considered risk. It served as a basis for describing the risk register and the matrix of risk. The study demonstrated that the most important threats resulting from the river regulation from the point of view of environmental protection are complete shading of watercourse bed, and in some cases, bed widening and deepening, embankments slope of 1: 1, 1: 0, embankments protection with stone material or their concreting

ECOLOGICAL RISK ASSESSMENT IN THE REGULATED WATERCOURSES

Ecological risk has not been identified well enough for the designers and contractors to take any actions for its limitation. It results from the lack of the basis formed to assess its level objectively. The aim of this study was to determine the standards useful in the evaluation of the ecological risk for aquatic plants in rivers, where it is planned to conduct regulatory works. The basis for the analysis were the results of the study performed in 2008–2014 in unmodified and transformed lowland watercourses in Lower Silesia. 41 study sections were analysed in 11 watercourses. 30 sections were located in regulated watercourses, while 11 were in unmodified streams. The research included vascular aquatic plants identification and the degree of the bottom coverage by these plants. As a result of regulatory works qualitative and quantitative changes in aquatic plants communities were observed. The analysis of these changes concerning the range and conditions of works conduction enabled assigning measures to the factors of the considered risk. It served as a basis for describing the risk register and the matrix of risk. The study demonstrated that the most important threats resulting from the river regulation from the point of view of environmental protection are complete shading of watercourse bed, and in some cases, bed widening and deepening, embankments slope of 1: 1, 1: 0, embankments protection with stone material or their concreting

VULNERABILITY OF THE BIOLOGICAL ELEMENTS OF RIVER BED ECOSYSTEM ON REGULATORY WORKS

The vulnerability of the system to changes is an additional factor often taken into account in risk analysis. Usually this assessment takes into account only two elements – probability and consequences of an event. The study attempts to assess the vulnerability of vascular aquatic plant communities to the qualitative and quantitative changes as a result of regulatory works in a river bed. The aim of the paper is to assess the possibility of using biological indicators, commonly used in assessing the status of aquatic ecosystems, as indicators of the vulnerability of analyzed communities. These are: the number of plant species, the degree of their bottom coverage, Shannon-Wiener diversity index, Pielou evenness index and ecological status. Field studies were carried out in growing seasons from 2008-2014 in small and medium-sized lowland watercourses in Lower Silesia. The field study included an inventory of vascular aquatic plants. Based on the results of the research values of biological indicators were calculated and statistical analysis (cluster analysis and Spearman’s rank correlation) were performed. On this basis it was found that the number of aquatic plants species and diversity index may be indicators of the vulnerability of plant communities to the changes as a result of river regulation

Hierarchia oddziaływania wybranych elementów systemu koryta cieku na rośliny wodne

W pracy podjęto próbę określenia hierarchii elementów systemu koryta cieku, które są kształtowane przez roboty regulacyjne i konserwacyjne, decydujących o składzie jakościowym i ilościowym zbiorowisk makrofitów wodnych. Badania terenowe wykonano w korytach 29 małych i średnich cieków nizinnych Dolnego Śląska. Na ciekach tych wyznaczono 100 odcinków badawczych. Badania obejmowały pomiar i opis wybranych elementów złożonego systemu koryta cieku, takich jak: spadek podłużny, szerokość dna, głębokość koryta, nachylenie skarp oraz sposób ich umocnienia, substrat dna, liczba gatunków roślin wodnych oraz pokrycie dna przez rośliny. Do określenia hierarchii oddziaływania rozpatrywanych elementów systemu cieku na skład jakościowy i ilościowy zbiorowisk roślin wodnych wykorzystano teorię zbiorów przybliżonych. Jej zastosowanie pozwoliło na określenie kolejności oddziaływania: pojedynczych elementów rozpatrywanego systemu koryta cieku, par tych elementów, zespołów złożonych z trzech oraz z czterech elementów na liczbę gatunków roślin wodnych występujących w cieku oraz na stopień pokrycia przez nie dna

Management of Alterations to Project Documentation – a Case Study of Water Supply and Sewerage Works

Background. The implementation of alterations to project documentation is the modification of certain solutions, assumptions or requirements. It mostly involves the verification or the specification of project documentation with regard to the actual conditions of execution or the investor’s expectations. The management of alterations in a construction project is aimed at predicting any negative consequences caused by changes in the investment process and their prevention or mitigation. Previous experience indicates that alterations to project documentation introduced during the execution of the work are widespread. They contribute to loss of time and increase in the cost of the project. For this reason, it is necessary to develop and implement an effective model for the management of such alterations.Research aims. The project manager, before construction, should be aware of any alterations to the project documentation that may have occurred during its execution, and their possible consequences. The aim of the study is to identify the causes, the structure and the consequences of alterations to project documentation with regard to water supply and sewerage construction.Methodology. The basis of the research and analyses constitute a detailed review of documentation compiled from eight projects in water supply and sewerage. Among the documents concerned, the “Records of Necessity” and “Records of Negotiations” were especially valuable for conducting the analysis.Key findings. The research conducted indicated the crucial role of the investor in the process of managing alterations to project documentation. The research revealed that proper preparation of the investment process, i.e. recruiting the best designers to prepare the project documentation, tracking changes in the nearer and farther surroundings, may significantly contribute to reducing or even eliminating many alterations to project documentation during the execution of the work

Applying the Analytical Hierarchy Process (AHP) into the effects assessment of river training works

The aim of the following study was to compare a few methods of river regulations and indicate the one which fully meets technical regulative standard and concurrently ensures protection of the watercourse ecosystem. According to the sustainable development rules it is of the most importance in every human activity to compromise between developmental and environmental needs of current and future generations. Therefore, both technical criteria related to flood safety and environmental ones were taken into consideration in the analysis. Field study was conducted in vegetation stage between 2008 and 2014 in small and medium lowland watercourses in Lower Silesia. The research comprised of measurements and descriptions of selected technical and environmental elements of a complex system of the watercourse river bed. Basing on obtained results a multicriterial assessment of the effects of the works was conducted. In order to assess the results an Analytic Hierarchy Process (AHP) was used in the study. It facilitated the creation of linear ranking of river beds and indicate the most optimal solution in terms of sustainable development. Such methods have not been applied in solving problems connected with river regulation. That’s why this study aims also at checking the utility of this method in decision making in both planning and regulation works realization. Results of the study indicate high usefulness of AHP method in the decision-making process

Application of Game Theory against Nature in the Assessment of Technical Solutions Used in River Regulation in the Context of Aquatic Plant Protection

The anthropogenic transformation of riverbeds causes a violation of the dynamic equilibrium of the river and its environment, threatening the ecological safety of aquatic ecosystems and dependent waters. However, the differing results of these transformations are dependent on many factors and it is difficult to determine them precisely before the works start. The designers and contractors of these works are dealing with the riverbed, which in terms of hydromorphological and biological features is variable, unique, and strongly diverse. Thus, decisions are followed by an unknown result concerning changes in the riverbed ecosystems. The aim of this study is to determine the suitability of game theory as a tool supporting decision-making in the design of regulatory works including ecological aspects, as well as an indication of a regulatory works model that would meet the expectations of water users while corresponding to environmentally friendly riverbed regulation. The analysis was made on the basis of observed changes in the number of species in aquatic plant vascular communities—one of the most important elements of a riverbed ecosystem. Using game theory, it is possible to create an effective tool for the design of regulatory works and decision-making process