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Hydropower and Floods
Published in Saeid Eslamian, Faezeh Eslamian, Flood Handbook, 2022
Sachin Kumar, Aanchal Singh S. Vardhan, Akanksha Singh S. Vardhan, R. K. Saket, D.P. Kothari, Saeid Eslamian
The most common cause of flooding is watercourses' incapability to drain away water during unusually heavy rainfall. Floods, however, are not always caused by heavy rainfall. They can result from other natural or human-made phenomena. For instance, inundation in coastal areas can be caused by a storm surge associated with a tropical cyclone, a tsunami, or a high tide, particularly when the rivers are flowing at a higher than normal river level. Inundation of normally dry areas can be caused by a dam failure, triggered, for example, by an earthquake. Other factors that may contribute to flooding include rivers or streams overflowing their banks, encroachment of encroaches land areas by sea-water during high tides, excessive rain (coupled with poor drainage system), a ruptured dam or levee, ground cover and topography, rapid ice melting in the mountains, and an unfortunately placed beaver dam. Flooding can also occur due to an earthquake-triggered landslide blocking the channel or when such a temporary dam is swept away due to increasing water levels. Coastal flooding occurs when a large storm or tsunami causes the sea to surge inland.
The Functional Significance of Selection of Particles by Aquatic Animals during Building Behavior
Published in Roger S. Wotton, The Biology of Particles in Aquatic Systems, 2020
By contrast with marine environments, many of the particles in fresh waters are too large to be sorted, or manipulated, by organisms. Consequently, there is much less evidence of modification of sedimentary characters by benthic animals, and comparatively fewer studies of bioturbation and sediment-water interactions.247 Beaver dams may have a major influence on stream community structure, through habitat modification and increased organic matter accumulation at impounded sites.248 Other effects include local alteration of carbon cycling due to increased methanogenesis.249
Critical evaluation of the hydrological, biological and sociological impacts of the implementation of flood control check dams in the Upper Marikina River Basin Protected Landscape, Philippines
Published in International Journal of River Basin Management, 2023
Rej Winlove M. Bungabong, Wade L. Hadwen, Larry V. Padilla
Though there are differences in community structure and characteristics, the results of this study were comparable to the studies conducted by Fuller and Peckarsky (2011) and Bagatini et al. (2012). Their studies showed that there were no differences between upstream and downstream abundances on beaver dam altered downstream ecosystems and 1st order stream impacted by agricultural areas. However, there may be instances when downstream sites may harbour greater diversity and richness when compared to upstream sites. One reason could be attributed to higher levels of pollutants in downstream sites that promote the proliferation and existence of pollution tolerant species, thereby contributing to the higher number of taxa (Kabore et al., 2016; Thorne & Williams, 1997). Presence of communities which was observed utilizing the stream for washing clothes and bathing, establishment and the proximity to main road of the downstream of Site 2 was the probable cause of the significant difference in total individual and taxa richness when compared to the upstream site.
Assessment of the hypolimnetic withdrawal system at Pine Lake, Alberta
Published in Lake and Reservoir Management, 2022
During the first year of operation, from 19 May to 2 September 1999, instantaneous flow in the pipe was roughly 43% of that predicted for lake levels on sampling days using a Hazen–Williams formula by AWARE Engineering Ltd (1997, Appendix D). Lower flows were recorded in late 1999 and again in late 2001 (Figure 2), when stainless-steel straps holding the concrete weights along some sections of the pipe snapped, allowing the pipe to float to the surface. The reason for this breakage of straps is not known, but expansion of the pipe against excessively tight straps may have been the cause (Sosiak 2002). Much heavier 907 kg fiberglass bags filled with gravel (Figure S5) were installed in October 1999 and 2001–2002 to sink the floating sections to the lake bottom. Venting pipes were also added to allow the escape of any gas (Sosiak 2002). Between October 1999 and July 2007, average pipe outlet flow was 82% of the predicted flow (Figure 2). Ice within sections of the pipe near the stilling basin and impounding of the pipe outlet by a downstream beaver dam may have also reduced pipe flow during the first 2 years of operation.
On dynamic naturalness, static regulation and human influence in the Ems-Dollard estuary
Published in International Journal of Water Resources Development, 2022
Karianne van der Werf, Herman Kasper Gilissen, Maarten Kleinhans, Marleen van Rijswick
How this coexistence of humans and nature should be regarded and when the presence of humans becomes a disruptive interference in natural systems can be illustrated by the example of beavers building a dam in a river, as they do in their natural way of living (Jones et al., 1994). If the river is only to follow its own natural course, the beavers can be seen as a disruption, for their actions cause the development of a lake upstream of the dam; the river may also change its course. On the other hand, if the beavers are viewed as a part of the greater ecosystem of nature, which also encompasses the hydro-morphodynamics of the river, the beaver dam is also part of the ecosystem, where beavers and river together find a new balance of coexistence. The extent to which humans build their more intrusive version of a beaver dam (including all adaptations and construction works) goes beyond coexistence, for it disrupts the functioning of the river and the ecosystem that the river supports. If problems such as the deteriorated ecosystem and the hyperturbidity of the Ems-Dollard are to be solved, the challenge for present and future restoration projects is to find a way of interconnected coexistence where both humans and the natural system can function in a healthy balance. Defining the ‘naturalness’ of the system should include not only the ecological components it is commonly limited to (Dussault, 2016) but importantly also the abiotic components, and even the interconnectedness with humans. The answer is not straightforward nor easy to accomplish, but a dynamic process towards an interactive equilibrium, just as the natural functioning of a natural system always demonstrates.