During the 20th century many floods of different intensity and extent have occurred on the Odra River and its tributaries. On the basis of long-term water level observations five major floods, that affected the entire upper and middle Odra River basin, were chosen for further analysis: June 1902, July 1903, August 1977, August 1985 and July 1997. However, hazardous floods were not only those that covered the whole upper and middle Odra River basin, so several local floods were also studied. Detailed historical analysis was made of meteorological conditions, with special emphasis on precipitation patterns and amounts. Then, on the basis of flood peak time occurrence, the stages of flood wave formation were formulated. The natural flood wave of the Odra River is often modified by hydro-technical infrastructure, the development and improvement of which is briefly described in this paper. In conclusion, a comparison of flood wave characteristics such as rising time, falling time, duration, peak flow and volume is presented. 相似文献
Methods for the identification of models for hydrological forecasting have to consider the specific nature of these models
and the uncertainties present in the modeling process. Current approaches fail to fully incorporate these two aspects. In
this paper we review the nature of hydrological models and the consequences of this nature for the task of model identification.
We then continue to discuss the history (“The need for more POWER‘’), the current state (“Learning from other fields”) and
the future (“Towards a general framework”) of model identification. The discussion closes with a list of desirable features
for an identification framework under uncertainty and open research questions in need of answers before such a framework can
be implemented. 相似文献
Flood stories in the Hebrew Bible and the Koran appear to be derived from earlier flood stories like those in the Gilgamesh Epic and still earlier in the Atrahasis. All would have their source from floods of the Tigris and Euphrates rivers.
The Gilgamesh Epic magnifies the catastrophe by having the flood begin with winds, lightning, and a shattering of the earth, or earthquake. Elsewhere in Gilgamesh, an earthquake can be shown to have produced pits and chasms along with gushing of water. It is commonly observed that earthquake shaking causes water to gush from the ground and leaves pits and open fissures. The process is known as soil liquefaction. Earthquake is also a possible explanation for the verse “all the fountains of the great deep (were) broken up” that began the Flood in Genesis. Traditionally, the “great deep” was the ocean bottom. A more recent translation substitutes “burst” for “broken up” in describing the fountains, suggesting that they erupted at the ground surface and were caused by an earthquake with soil liquefaction. Another relation between soil liquefaction and the Flood is found in the Koran where the Flood starts when “water gushed forth from the oven”. Soil liquefaction observed erupting preferentially into houses during an earthquake provides a logical interpretation if the oven is seen as a tiny house. A case can be made that earthquakes with soil liquefaction are embedded in all of these flood stories. 相似文献
The internal architecture of the immense volumes of eruptive products in Continental Flood Basalt Provinces (CFBPs) provides vital clues, through the constraint of a chrono-stratigraphic framework, to the origins of major intraplate melting events. This work presents close examination of the internal facies architecture and structure, duration of volcanism, epeirogenetic uplift associated with CFBPs, and the potential environmental impacts of three intensely studied CFBPs (the Parana-Etendeka, Deccan Traps and North Atlantic Igneous Province). Such a combination of key volcanological, stratigraphic and chronologic observations can reveal how a CFBP is constructed spatially and temporally to provide crucial geological constraints regarding their development.
Using this approach, a typical model can be generated, on the basis of the three selected CFBPs, that describes three main phases of flood basalt volcanism. These phases are recognized in Phanerozoic CFBPs globally. At the inception of CFBP volcanism, relatively low-volume transitional-alkaline eruptions are forcibly erupted into exposed cratonic basement lithologies, sediments, and in some cases, water. Distribution of initial volcanism is strongly controlled by the arrangement of pre-existing topography, the presence of water bodies and local sedimentary systems, but is primarily controlled by existing lithospheric and crustal weaknesses and concurrent regional stress patterns. The main phase of volcanism is typically characterised by a culmination of repeated episodes of large volume tholeiitic flows that predominantly generate large tabular flows and flow fields from a number of spatially restricted eruption sites and fissures. These tabular flows build a thick lava flow stratigraphy in a relatively short period of time (c. 1–5 Ma). With the overall duration of flood volcanism lasting 5–10 Ma (the main phase accounting for less than half the overall eruptive time in each specific case). This main phase or ‘acme’ of volcanism accounts for much of the CFBP eruptive volume, indicating that eruption rates are extremely variable over the whole duration of the CFBP. During the waning phase of flood volcanism, the volume of eruptions rapidly decrease and more widely distributed localised centres of eruption begin to develop. These late-stage eruptions are commonly associated with increasing silica content and highly explosive eruptive products. Posteruptive modification is characterised by continued episodes of regional uplift, associated erosion, and often the persistence of a lower-volume mantle melting anomaly in the offshore parts of those CFBPs at volcanic rifted margins. 相似文献
The major obstacles for modelling flood processes in karst areas are a lack of understanding and model representations of
the distinctive features and processes associated with runoff generation and often a paucity of field data. In this study,
a distributed flood-modelling approach, WetSpa, is modified and applied to simulate the hydrological features and processes
in the karst Suoimuoi catchment in northwest Vietnam. With input of topography, land use and soil types in a GIS format, the
model is calibrated based on 15 months of hourly meteorological and hydrological data, and is used to simulate both fast surface
and conduit flows, and groundwater discharges from karst and non-karst aquifers. Considerable variability in the simulation
accuracy is found among storm events and within the catchment. The simulation results show that the model is able to represent
reasonably well the stormflows generated by rainfall events in the study catchment. 相似文献
