The execution of work in hydro-engineering and land reclamation takes place in difficult conditions, because of the presence of water, the variety and changeability of conditions, the changes of the work-stands and work-fronts, the seasonal employment of the workers, the necessary of interference in the environment. This attributes result in appearing of different risk types. In this paper we present the identification and description of factors generating the unpunctuality of work execution. These factors are presented on a Ishikawa diagram. These are: management of investment process, organization and technology of work, machines, workers, building materials. These factors were divided in subfactors which are the sources of breach of contract of the time limit realization. These subfactors are: insufficiency of funds, absence of modern technologies, high work costs, seasonality and special requirements of work execution, necessity of nature protection in the water-course bed, incomplete dates of work quantity, absence of standard work time, planning using method with sequence work execution, planning of the work execution by deterministic methods, difficult selection of machine parameters, variety and changeability of work field, using of alternative schemes, inconvenient weather conditions, limited accessibility to the work-station, technical and organization breaks, tough and dangerous work conditions, deficiency ...
This paper describe the possibility to application the benchmarking for betterment the executing of maintenance works from the point of view the flora and fauna protection on water-course bed. Benchmarking used in the engineering and business gives in many cases profitable results. This method was don’t be used in executing works of water engineering and land reclamation. By the main-tenance work the essential problem is the effective protection of biocenosis on the water-course bed, because the conditions in work execution are changeable. Also the plant and animal community on the water-course bed, the slopes the coastal zone are changeable. The proecological activity consist in analysis of the ecolo-gical risk, properly time-limit to executive the maintenance-works, application of alternate technological schemes and machines suitable machine equipment. These activities can have a positive influence on ones kind of organisms and inadequate-ly on another organism. The evaluation of those activities is the changes of orga-nisms quantity as the consequence of executive works on water-courses. In this paper those consequence has been shoved on an example of six water-invertebrates Tubifex tubifex, Galba palustris, Gammarus pulex, Asellus aquati-cus, Limnophilus flavicornis and Ephemera vulgate. For three of them this – Tubi-fex tubifex, Galba palustris, and ...
In this paper we described the process of watercourses maintenance and analysed the problems involving its quality management in terms of the water-course efficiency. The watercourse efficiency is determined by running waters use and maintenance works. Both actions are characterized by good quality when the good technical condition of the river-bed, its capacity and the good ecological status are provided. River-bed capacity ant the ecological status of the running waters are influenced by the aquatic plants. Therefore control and assessment of aquatic plants abundant are major elements of the quality management of the wa-tercourses efficiency.To identify the problem of overgrowing of running waters with plants, the lowland watercourses in the Lower Silesia were investigated during the years 2007-2009. Field studies showed, that the overgrowing of river-bed begins straight after the maintenance works. Generally the aquatic plant development is rapid. Therefore the correct watercourse maintenance demands cyclical mainte-nance works. Maintenance works comprise a lot of technical actions, which are related to each other. In this paper we showed, that each of these actions affects the watercourse efficiency. The field studies and analysis proved, that quality management of the watercourses maintenance requires establishment criteria of the process quality assessment. Criteria should consider ...
This paper presents the ecological risk factors related to the watercourses regulation and maintenance works on the small and medium-sized lowland water-courses found in Lower Silesia. These factors include: occurrences related to the execution of regulation and maintenance works, which have an impact on the eco-logical condition of the watercourses, probability of these occurrences and their consequences in the form of adverse ecological changes in the river beds. Based on the observed responses of aquatic vascular plants species to the technical inter-ference on a watercourse's bed, a detailed assessment of one of these factors - ecological changes in the watercourse's bed was made. Field studies were con-ducted during 2007-2008 on 44 sections of various unregulated, conserved and regulated watercourses. Research included identifying the species of aquatic macrophytes found in the streambed as well as determining the degree of cover-age.The field studies showed, that the regulation and maintenance works had an adverse impact on the aquatic plant species composition. In most cases species removed during the technical interference did not regenerate. In some transformed study sections the plant species abundant was lower than on the unregulated tran-sects. Only in rare cases the plant species abundant in the compared study sec-tions was ...
This paper presents an assessment on the ecological status of various low-land watercourses found in Lower Silesia, determined by using aquatic macro-phytes as the primary biological indicator on the health and condition of such wa-tercourses. Field studies were conducted during 2007-2008 on various unregulated, conserved and regulated watercourses. Research included identifying the species of aquatic macrophytes found in the streambed as well as determining the degree of coverage. On this basis was the RI index calculated and the ecological status of watercourses defined.The field studies showed, that the watercourse's ecological status depends on many factor. To identify those factors we analyzed the correlation between the class of watercourse's ecological status and technical parameters like: bottom width, watercourse's depth, inclination of the slope and longitudinal profile. The analysis showed that the impact of channel parameters on the ecological condition of watercourses was similar in the case of natural watercourses and those that were transformed as a result of technical interference. However based on the survey cannot be found, that the technical parameters of watercourse's bed shaped as a result of regulatory and maintenance works affect the improvement or the dete-rioration of the ecological status. This follows from the fact that the ...
Construction works in the open air, in particular laying sewage systems, are susceptible to weather conditions. Weather conditions, such as very high or low emperatures, strong winds, intense and prolonged precipitation, interfere with work and they can even lead to cessation of construction. In consequence, the construction work lasts longer than originally assumed. On the other hand, it is impossible to alter weather. Therefore, it is vital to conduct a thorough identification of threats related to adverse weather conditions. This work makes an attempt to determine basic relationship between adverse weather conditions and the possibility of completing construction work according to a schedule. This analysis is a part of Schedule Risk Assessment. The findings show that the frequency of adverse weather occurrence is high and it affects schedule risk with special regard to air temperatures below -5°C and above 25°C. Thus, before starting construction, the probability of adverse weather conditions should be considered. Accurate identification of weather factors during the planning phase may help in accumulation of adequate reserves. Therefore, any unavoidable circumstances that are forced by adverse weather seem to be allowed in the schedule. This work focuses on air temperature, precipitation and wind because of their ...
Occurence of minus air temperature, precipitation and wind worsen tech-nical conditions of the performance of maintenance works and it also has an impact on the occupational safety. Some of the results of considered weather events are the delays in the performance of particular works and an increase of their costs in a result of additional works. Potential financial loss that may influence enterprise in a result of unfavourable weather conditions is determined as the weather risk. In the following research the level of the risk in maintenance works in watercourses was assessed. The analysis of the weather forms was conducted in Wrocław between 2000 and 2011 for that purpose. Three weather conditions such as the air temperature below 0, rainfall, snowfall and the velocity of the wind were considered. Analysis was conducted basing on the data obtained from the Wroclaw Airport station. It was performed for the period recommended for the performance of maintenance works in watercourses from the 1st to the 31st of December. Frequency of the days occurence while weather conditions constituted an obstacle was determined basing on the obtained data. The analysis revealed that unfavourable weather conditions occurred often in realization of the works in the considered ...
The following study presents an assessment of the influence of fascine and stone scarp`s reinforcement on the quantitative and qualitative composition of vascular water plants. The analysis was based on field results obtained between 2007 and 2008, and 2011-2012. The research was performed in four small and medium lowland watercourses located in Lower Silesia were 16 study sections were established. These sections varied in the material used for scarps` reinforcement. The field research included identification of vascular water plants occurrence in the river bed and determination of the degree of their bottom coverage. These factors served as the basis for Shannon-Wiener biodiversity index calculation. Jaccard`s species similarity index was used for the assessment of similarities among water plants communities in different study sections. Conducted research indicates that the choice of the scarp`s reinforcement has an impact on analyzed plant indexes and it does not undergo any changes re-lated to time. However, positive indexes change has been reported in water plants communities. ...
The aim of the following research was an assessment of the impact technical interference has over Smortawa riverbed`s hydromacrophytes communities. The measure of this impact based on the following four biological factors: the number of species, the degree of the bottom coverage, Shannon-Wiener index and Macrophyte River Index. Field study was performed in vegetation season of 2012 in three river sections presenting different degree of anthropogenic modification: natural, modified moderately in the result of ecoregulation and severly modified in the result of technical interference. In order to assess the impact of modification on the quality and quantity of hydromacrophytes communities Spearman`s ranks correlation analysis was performed. Performed analyses indicated that the biodiversity of biological indexes in study sections in linked with the range of works conducted in the riverbed. Stronger connection with these factors showed elements of the watercourse system modified in a result of technical interference such as: river filing, shape of the riverbed, width of the bottom and the way of scarp`s strengthening and shading the watercourse. ...
This paper attempts to assess an effect of the range of regulatory works in watercourse beds on the aquatic plant communities. The results of field studies carried out on sections transformed as a result of regulatory works and the non-altered sections were compared for this purpose. The field studies were conducted in growing seasons in years 2008-2014 on 11 small and medium-sized lowland watercourses in Lower Silesia. They included identification of aquatic plant species and estimation of the degree of bottom coverage with them. The assessment was based on analysis of changes in the values of five biological indicators such as: the number of aquatic plant species, Jaccard similarity coefficient, ecological status, Shannon-Wiener biodiversity index and Pielou`s evenness index. Comparative analyzes enabled to determine the qualitative and quantitative changes in the aquatic plant communities. However, they did not show any correlation between the analyzed biological indicators and the range of regulatory works in watercourse beds. ...
Every water-course is a complicated system which consists of technical and natural elements. The number of these elements and the connections between them are little-known. The aim of the studies was to evaluate the effect of chosen system elements on the aquatic plant communities on the bottom. Longitudinal profile, bottom width, watercourse depth, substrate, level of bed silting, inclination of the slopes, slope protection and the time from the last interference in watercourse’s bed (regulation, maintenance works) were the chosen system elements. The basis of this paper were field studies, which were carried out in 13 small lowland watercourses in the Lower Silesia during the vegetation season in year 2007. For estimating the results of the studies, the rough sets theory was used. On this basis the hierarchy of the influence of elements of the water-course’s bed on the makrophyten communities was determined. ...
This paper presents the evaluation of the risk factors in the watercourses which will be regulated or maintained in the future. The analysis concerns one of the components of the ecological risk – the risk of the qualitative and quantitative changes by the aquatic plant communities. The basis of the analysis were field studies, which were carried out during the years 2007-2008 in six lowland water-courses in the Lower Silesia. On the river beds there were executed regulation or the maintenance works. The field studies comprised identification of aquatic plant species and es-timation of their cover-abundance. For the abundance analysis we used the Braun-Blanquet Scale. At the natural transects the number of aquatic plant spe-cies ranged from 4 to 7, and abundant from 5 to 100% of the bottom surface. At the altered stretches the number of aquatic plant species ranged from 0 to 5. The plant abundant did not exceed 25% of the bottom surface. On the ground on these dates were prepared a maps of ecological risk, which can be used in planning and execution on watercourses regulation and maintenance works. ...
The construction process begins with the formulation of an idea for the project and finishes with the final commissioning. This consists of many stages, the most important of which is the construction of the buildings for the facility. This results from the specific features of the construction project, such as its long duration, its uniqueness, the seasonality of the work, dependence on weather con-ditions, and the necessity of interfering with the environment. There are many more factors, and when we consider the construction of a treatment works plus the sewerage system itself, we must also take into account any special requirements connected with their function in the local water and sewage management system. All these factors generate the risk exposure. Such risks should be included in the initial project-costing, schedule planning, and establishing the duration of the work. Events which can occur during the building of the sewage treatment works and the sewerage system have been detailed in this paper. Such events can lead to cost overruns and the prolonging of the construction phase. The method known as expert interview was used to establish whether the pre-prepared list contained the most important sources of risk. The specialists, all with long ...
Surveys, documentation reviews and direct observation on the building sites point to a number of "exposures", which can have a negative influence on the sewerage's projects completion. Such exposure occur at every stage of the project. The most important among them are errors in the construction project, materials' defects and damages and disadvantageous meteorological conditions. They cause a high level of quality, schedule and cost risk. Risk response development can lower the level of risk. In this paper a risk response matrix was used to achieve this purpose. This technique is used in a risk management plan. The activities, which allow the achievement of a lower frequency of risk and reduction in their consequence have to be determined by this technique. This paper indicates that activities based on risk avoidance and mitigation have their best application in sewerage's projects. These include: tightening contractor selection's criteria, a detailed contract and contingency reserves. Analysis of risk response development indicates that to lower levels of quality, schedule and cost risk throughout a project suitable action should be taken as early as at the planning phase and the contract stage.
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The following study concerns an assessment of ways of the littoral zone management in both small and middle lowland watercourses on the composition of hydromacrophytes in water communities. The research was performed between 2007 and 2012 in 20 study sections located in Lower Silesian watercourses. The research included an assessment of the development of the littoral zone and identification of water hydromacrophytes and determination of the level of their bottom coverage. Each study section had a Shannon-Wiener biodiversity, Pielou evenness and species shortage indexes calculated. Results of the following study indicate that ways of using the littoral zone have a significant influence on analyzed vegetal indexes. The highest values were observed in study sections where littoral zones were such as:. uncultivated lands such as wetlands, bushes and tall herbs. While the lowest observed values in all compared indexes were noted in forest sections. ...
