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Flood Analysis
Published in Ian Watson, Alister D. Burnett, Hydrology, 2017
Ian Watson, Alister D. Burnett
Flood routing is the general term embracing a variety of techniques used for predicting what happens to a flood-flow surge, or wave, as it moves downstream. This may consist of a simple graphically-derived prediction of the flood level (stage elevation) at some location on the downstream reach of a river, based on an observation of a flood-stage elevation upstream. At a more advanced level flood routing may comprise a computer prediction of the flood discharge and the time of occurrence of this discharge over the spillway of a downstream dam, or along a downstream reach of river.
Floodmark and Its Areas of Applications
Published in Saeid Eslamian, Faezeh Eslamian, Flood Handbook, 2022
Niranjan Bhattacharjee, Ratneswar Barman, Saeid Eslamian
Normally the level at which the river overflows its banks and inundates the adjoining areas of a river is called the flood stage [24]. In Webster's New International Dictionary, flood is defined as “a great flow of water especially a body of water, rising, swelling and overflowing land not usually covered; a deluge, a freshet and, an inundation.”
Lithofacies characteristics and sedimentary model of a gravelly braided river-dominated fan: a case study of modern Poplar River alluvial fan (northwest Junggar Basin, China)
Published in Australian Journal of Earth Sciences, 2021
D.-W. Liu, Y.-L. Ji, C.-L. Gao, J. Zhong, Y. Qi
The main lithofacies associations during the flood stage are the FC and S1 deposits in the proximal region of the alluvial fan. The fan surface can be divided into sedimentary active and non-active zones. In active areas, the energy of the floodwater is very high and large amounts of sediments are transported. Flow carried sediments are rapidly deposited on the fan, filling the channels and forming the FC channel deposits. Then, as the accommodation space in channels gradually decreases, floods overflow the gullies and form unlimited S1 sheet-flow deposits, which require sloped geomorphic conditions and high hydrodynamic conditions (Blair, 1999a, 2000). Therefore, a large proportion of thick layer sheet-flow sediments are produced in the proximal region. On the related outcrop sections (Figure 11), the sequence changes through the flood phase can be identified, although the interphase surface is difficult to compare. In general, the FC deposits gradually change to S1 deposits in the proximal region owing to the controlling hydrodynamic and geomorphic factors (De Haas et al., 2014), and on outcrops depositional environments show changes in the vertical direction (Figure 16a).
Scalable Feature Tracking for Finite Element Meshes Demonstrated with a Novel Phase-Field Grain Subdivision Model
Published in Nuclear Technology, 2021
Cody J. Permann, Andrea M. Jokisaari, Michael R. Tonks, Daniel Schwen, Derek R. Gaston, Fande Kong, Robert Hiromoto, Richard C. Martineau
After the flood stage completes, each processor contains the data structures for several partial features found within their respective partitions. However, only a small subset of this information needs to be shared with processors involved in constructing a complete global feature map. Specifically, ghosted element information within each feature is shared to facilitate stitching. For algorithmic efficiency, we also construct an axis-aligned bounding box that completely contains all interior and halo elements for each feature. Several other pieces of information detailed here are also serialized to be sent to a subset of processors responsible for stitching. If a feature lies on a boundary of the domain and the simulation has periodic boundary conditions applied (Sec. II.F), those boundary node IDs are also saved in the feature’s data structure. Next, the lowest element ID representing the feature is saved for parallel agnostic sorting purposes. This sorting ID is discussed more thoroughly in Sec. II.D. Finally, the halo set introduced in Sec. II.A is adjusted to remove all entries that would make up any part of the interior of the completely stitched feature. This reduces the amount of data that must be communicated for all further stages of the algorithm.
Revisiting hysteresis of flow variables in monitoring unsteady streamflows
Published in Journal of Hydraulic Research, 2020
Marian Muste, Kyutae Lee, Dongsu Kim, Ciprian Bacotiu, Marcela Rojas Oliveros, Zhengyang Cheng, Felipe Quintero
The present discussion revolves around flow situations where the unsteadiness-induced hysteresis acts in isolation from other potential causes (e.g. effects of instream vegetation, bedform-induced roughness development, and baseflow–stream interactions). From the same perspective, we analyse flood wave propagation in channels predominantly controlled by friction (channel control) rather than channel geometric features (local control) (WMO, 2010). In addition, the hysteresis-related aspects are discussed only for stages up to bankfull stage (i.e. flood stage), as the mass and momentum exchanges that occur between the main channel and floodplain above this stage generate additional flow complexities that impede the interpretation of the process of interest herein. Finally, it is assumed that there are no issues related to instrumentation deployment and operation, as these factors can also produce hysteresis due to improper sensor positioning and time synchronization. Under the aforementioned conditions, the major contributor to hysteresis is the flow unsteadiness that is well-described by mean flow governing equations for unsteady flow as presented in, for example, Henderson (1966) or Fenton and Keller (2001).