Strength and permeability properties along with microstructural evolution of hardened slurries composed of fly ash from fluidal bed combustion of brown coal and an addition of OPC/BFSC is assessed in this paper. An increase in the amount of fly ash in slurries influences the development of mechanical strength and a decrease of hydraulic conductivity. SEM, XRD, and porosity analyses confirmed formation of watertight microstructures. The structure of slurries is composed of ettringite, C-S-H phase, AFt, and AFm phases. Ettringite crystallises as relatively short needles forming compact clusters or intermixed with the C-S-H phase. The occurring C-S-H phases are mainly of type I – fibrous and type II – honeycomb
Runoff estimation is a key component in various hydrological considerations. Estimation of storm runoff is especially important for the effective design of hydraulic and road structures, for the flood flow management, as well as for the analysis of land use changes, i.e. urbanization or low impact development of urban areas. The curve number (CN) method, developed by Soil Conservation Service (SCS) of the U.S. Department of Agriculture for predicting the flood runoff depth from ungauged catchments, has been in continuous use for ca. 60 years. This method has not been extensively tested in Poland, especially in small urban catchments, because of lack of data. In this study, 39 rainfall-runoff events, collected during four years (2009–2012) in a small (A=28.7 km2), urban catchment of Służew Creek in southwest part of Warsaw were used, with the aim of determining the CNs and to check its applicability to ungauged urban areas. The parameters CN, estimated empirically, vary from 65.1 to 95.0, decreasing with rainfall size and, when sorted rainfall and runoff separately, reaching the value from 67 to 74 for large rainfall events.
Formation of cities was always dependent on water. Location over the water areas gave the opportunity for develop-ment and increase of prosperity. And although water was also a threat and cause of damage, the benefits of its neighbour-hood prevailed. Today, the challenge for developing cities is a climate change observed in recent decades, which results in violent natural phenomena, e.g. floods and hurricanes. One of the main problems faced by residents of housing estates lo-cated on the water is the increasing risk of flooding. Actions are taken to adapt the functioning of the urban structure and buildings to new water conditions. Currently, the process of floodplain development is progressing on a larger scale. This phenomenon is intensifying and as a result many housing estates are created in areas exposed to flooding. The approach to flood issues in the context of architecture and spatial planning has evolved in recent decades. The new water paradigm is expressed in striving to keep it in place.
How did the settlement in the floodplains look once and today in Warsaw? The research study was preceded by a his-torical feature and then the article drew attention to the ways of shaping new housing estates in flood areas in Warsaw. Us-ing the case study method, new housing estates developed in the flood plains have been analysed, with a listing of their strengths and weaknesses and the assessment of solutions. Issues were discussed on how to protect the buildings from the harmful effects of water. On the basis of the conclusions from the Warsaw case study, project guidelines for floodplains in Warsaw were developed, the aim of which was to identify the most important priorities in the development of floodplains and increase the security of investment arising in these areas.
The paper presents the results of studies on the influence of the 2010 Vistula flood on the humification process in the bottom sediments of the Goczałkowice Reservoir in southern Poland. Due to its location in the vicinity of farmlands, forests and urbanized areas, the Goczałkowice Reservoir is characterized by amplified and intense humification processes within its sediments. The studies were focused on the determining the influence of the flood wave containing organic and inorganic suspensions on these processes. Humic acids were analyzed using two spectroscopic methods: Electron Paramagnetic Resonance (EPR) and Fourier Transform Infrared Spectroscopy (FT-IR). Application of these methods allowed to determine the values of free radicals and of the g-factor, which are indicators of oxidation, aromatization and maturation of humic acids during the humification process, as well as the value of the 1650/1720 ratio, reflecting the dissociation of the COOH group to COO− and the formation of complexes of transitional metals with humic acids during the humification process.
This study presents the results of a comprehensive geoarchaeological study implemented at an archeological site covering ca. 5 ha near the city of Csorna on the NW part of the Danube Plain, NW Hungary. The site itself exposed a complex fluvial system of an ice age creek with near bank and overbank areas (levee, point bar, back swamp). Spatial distribution of archeological features allowed for the interpretation of differential use of the fluvial landscape by different cultures. According to our data, the referred fluvial system must have emerged during the Late Glacial. At this time, creeks originating from hills to the SE followed a uniform NW trajectory. From the Holocene, small creeks were beheaded turning into inactive flood channels. It was the time when the gradual infilling of the floodplain started. Alternating layers of floodwater coarses and floodplain fines mark recurring floods at our site. These could have been correlated with cooler, wetter climatic phases of the North Atlantic, Western Europe and high stands in Central European lakes. Highest floods are recorded during the Late Bronze and Iron Ages besides the Neolithic. Pollen data enabled us to make inferences on the vegetation as well.
The situation when groundwater considerably rises above the “normal” level, water intake, lowering of groundwater levels and other relevant practical tasks require the drainage facilities. The most effective techniques of numerical studies of the corresponding boundary problems at present time are methods of dealing with inverse boundary value problems (conformal and quasi-conformal mappings). As basis of this research we used the case of combining the fictitious domain methods with quasi-conformal mappings of the solution of nonlinear boundary value problems for the calculation of filtra-tion regimes in environments with free boundary areas (depression curves) and zones of “mountainous” areas. This paper reviews the stationary issue of flat-vertical stationary non-pressure liquid filtration to horizontal symmetric drainage. In the paper a practical methodology for solving boundary value problems on conformal mappings is suggested for the calculation of the filtration process in the horizontal symmetrical drainage. The idea of block iterative methods was used during the creation of the corresponding algorithm which is based on the alternating “freeze” of the anticipated conformance parameter, the internal and boundary connections of the curvilinear area. The results of the conducted numerical calculations confirmed the effectiveness of the suggested problem formulations and algorithms of their numerical solution and the possibility of their use in the modelling of nonlinear filtration processesoccurring in horizontal drainage systems, as well as in the design of drainage facilities and optimizing other hydrosystems. Therefore these results are of great importance.
During the last few years, the City of Bechar in Algeria has witnessed some extreme events, such as the great flood of the year 2008 in which an exceptional amount of rain was recorded with a flow rate of 830 m3∙s–1 (hwater = 4 m, b = 200 m); similar flooding also occurred in 2012 and 2014. The problem is that most of the City of Bechar has an urban sprawl that extends to the banks of Wadi Bechar, which represents a huge risk for the lives of the inhabitants of the region. The present work aims to assess the flood risk through flood hazard mapping. This method consists in determining the flow rates for the return periods of 25 years (Q25 = 388.6 m3∙s–1, hwater = 3.5 m, b = 200 m, Sspot = 55.35 ha), 50 years (Q50 = 478.3 m3∙s–1, hwater = 5 m, b = 200 m, Sspot = 66.48 ha) and 100 years (Q100 = 567.3 m3∙s–1, hwater = 7 m, b = 200 m, Sspot = 133 ha). For this, it is necessary to adjust the flow rates using Gumbel law along with some computer supports such as HEC-RAS, HEC- -GeoRAS and ArcGis for mapping the event. Finally, this work enables us to determine the zones exposed to risk of flooding and to classify them according to the flood water height.
Poland is among the countries that are facing water stress, although we largely remain accustomed to having water always there when we need it. Should we take this unrestricted access for granted?
Weed competition in southern Brazil is one of the main limiting factors for Oryza sativa L. (flooded rice) yield. Echinochloa spp. (barnyardgrass) occurs at a high frequency. Although the potential for weed interference in this cereal is well known, there is little information available about the impact of nutrient competition on rice. Thus, this study aimed to evaluate the relationship between the increase of the barnyardgrass population and the development and nutrition of flooded rice plants at different stages of development. The treatments consisted of growing populations of barnyardgrass competing with the crop from stage V4, which were: 0, 1, 6, 13, 100 and 200 plants · m−2. The experimental design was randomized blocks with two replications, and the experimental units were plots 1.53 m wide by 5 m long. Plant biomass, nutrient uptake and loss of productivity were determined with three replications. An increase in the barnyardgrass population reduced the dry mass of rice leaves and stems, regardless of the evaluation period and the vegetative or reproductive period. Barnyardgrass plants had a significant impact on the reduced grain yield of a flooded rice crop, mainly due to high nutrient competitiveness, especially N in the vegetative period and K in the reproductive period. Barnyardgrass caused a loss of yield by unit · m−2 of 1.13%. The competition for N between rice and barnyardgrass plants was higher in the vegetative period, while for K, Ca and Mg the highest competition occurred in the reproductive period.
Flood with intense rainfall and inadequate drainage system leads to flood inundation in residential areas, which in turn damages the housing components and causes a loss. The different level of flood inundation at various affected locations caused varying degrees of losses. This study aimed to identify the damage conditions and analysed the physical loss of the residential building components. The physical vulnerability level is influenced by two damage qualification: the structural and architectural damages. The third-order polynomial function approach produces the best model for both qualifications, yielding the smallest average of errors (RMSE) of 0.0187 for the structural quality and 0.0672 for the architectural quality. The amount of losses related to the architectural elements of the house is smaller compared to the structural one as it is not its main component. This approach is useful as a guide in determining the post-flood handling rehabilitation cost of both structural and architectural elements that will be more appropriate for future conditions. This information is essential as effective management to design flood disaster mitigation strategies and may serve as a basis for flood risk management.
Two-third of the area of the Netherlands is flood prone. Storm surges at the North Sea, floods in the rivers, failure of secondary dikes, as well as heavy rainfall may cause flooding. Most of the flood prone areas rely for their existence on drainage by pumping, because their surface level may be permanently or during floods up to several metres below the surrounding water levels. During the past decades climate change is generally felt as a reason for major concern. However, the impacts of climate change on increase in extreme conditions may be up to 45% per century. If we look at the man-induced changes in land use, due to increase in population and rapid increase in the value of public and private property, then one may observe an increase of 100–1,000% per century. One should therefore wonder what would have to be our major concern.
In the paper the relevant processes are described, based on some characteristic data on water management and flood protection in the Netherlands. It is shown that impacts of climate change on water management and flood protection may be expected, but that such impacts can easily be accommodated during improvement works on water management systems and flood protection provisions that from time to time will be required. It will be much more important to take carefully into account the risk of flooding in the planning of land use development, especially for valuable types of land use like urban and industrial areas, green houses and recreation areas.
Flood risk management are considerably influenced by several factors, such as all sources of flooding, social circum-stances, policy and even the potential for local economic growth. To encourage government, business, community and oth-er parties to continue investing in flood risk management projects, it is necessary to give understanding that the projects can also provide economic benefits through systematic predictions and assessments of costs, benefits and social values, espe-cially on flood-affected communities. This study aims: (1) to develop knowledge and understanding on small-scale flood risk management project in Malang City, Indonesia, and; (2) to assess the economic efficiency of the project investment considering all benefits, both monetary and non-monetary. The research method is a mixed method combining quantitative questionnaires (N = 53 from 162 families) with qualitative in-depth interviews (N = 10) and field observations. The runoff discharge and the inundation depth were calculated using hydrology and hydraulic analysis, while the economic efficiency was analysed using cost benefit analysis (CBA). The results show that the community-based flood risk management system can reduce the flood risk up to 30% compared to before the implementation of that system. This system also provides direct financial benefits through the use of drainage channels for fish and vegetables farming. It causes the increase of the net so-cial benefit about 70–90% and the net present value (NPV) greater than zero (NPV > 0). Therefore, the project investment is recommended to be proceeded.
The aim of the study was to analyse the state of flood-prone areas development in 10 towns on the Warta River in the Wielkopolska region in terms of the possibility of adapting existing and planned buildings to flood risks. A significant percentage of the areas exposed to floods was the basic criterion for selecting three towns for the second stage of the research. The analysis of the content of 22 local spatial development plans (LSDP) in three selected towns has revealed that the plans for special flood hazard areas (SFH) and embanked areas lack precise requirements for flood adaptation. The research proved that small riverside towns in Wielkopolska region insufficiently use planning tools to create appealing and resilient waterfronts and reduce their vulnerability. New buildings not adapted to changing water levels are still being built in the flood-prone areas, because LSPD plans do not impose such requirements. The authors proposed the graphical analysis method (based on overlay maps), which allows to indicate the areas requiring special flood-adaptation guidelines. The building and site recommendations in LSDP should refer to BFE level and may include various types of amphibious architecture and their location conditions, which has been identified in the study.