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This paper is to present an efficient approach to enriching the quantification model of human-riverine interactions and its anthropogenic impact by a retrospective study on one of the four most famous historical hydraulic projects in China,the Tuoshan Weir.It was constructed in 833 AD and had trajectories of natural resilience and hydraulic engineering maturity more than thousand years.Extensive historical data and maturation procedure of the hydraulic system were used judiciously to examine the spatial patterns of the long-term water conservancy system with agriculture,urbanization and civilization of Ningbo City in Zhejiang Province,Southeast China.Interaction framework is assessed from historical perspective and the deposition rate(DR)is calculated by analyzing the continuous increase of the Tuoshan Weir height.The results show that the declining DR during the 1180 years guaranteed the beneficial role the Tuoshan Weir played in spite of some negative river responses caused by the increase of sediment deposition and decrease of fresh water-retention capacity.The following up revamped workings and well matured hydraulic system around the Tuoshan Weir also contribute a lot to the designed mission of the weir.We conclude that hydraulic system maturation is very important for the proper function and life span of huge hydraulic projects. 相似文献
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SPH simulation of free surface flow over a sharp-crested weir 总被引：1，自引：0，他引：1
In this paper the numerical simulation of a free surface flow over a sharp-crested weir is presented. Since in this case the usual shallow water assumptions are not satisfied, we propose to solve the problem using the full weakly compressible Navier–Stokes equations with the Tait equation of state for water. The numerical method used consists of the new meshless Smooth Particle Hydrodynamics (SPH) formulation proposed by Ferrari et al. (2009) [8], that accurately tracks the free surface profile and provides monotone pressure fields. Thus, the unsteady evolution of the complex moving material interface (free surface) can been properly solved. The simulations involving about half a million of fluid particles have been run in parallel on two of the most powerful High Performance Computing (HPC) facilities in Europe. The validation of the results has been carried out analysing the pressure field and comparing the free surface profiles obtained with the SPH scheme with experimental measurements available in literature [18]. A very good quantitative agreement has been obtained. 相似文献
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H. F. L. Williams 《Environmental Geology》1995,26(3):166-171
Ten cores were obtained from a marsh developed along Mad Island Slough, Texas, USA, upstream of a weir constructed in 1948. The cores were analyzed for cesium-137 to identify time-stratigraphic marker horizons and calculate recent sedimentation rates. The cesium-137 analysis provided a 1954 marker horizon in nine of the ten cores. A second marker horizon, present in all ten cores, consisted of an abrupt downcore change in lithology from dark organic-rich muds to grey organic-poor sands. This transition was tentatively identified as coinciding with 1948 and the beginning of marsh sedimentation. Resulting sedimentation rates show that surprisingly little sedimentation has occurred behind the weir, averaging only 27 cm in almost 50 years. Sedimentation rates in the marsh declined from an average of 2.4 cm yr–1 in 1948–1954 to 0.32 cm yr–1 in 1954–1994. A similar trend of declining sedimentation has been documented for adjoining Mad Island Lake, suggesting that land-use changes in the lake's watershed have reduced the sediment supply in recent decades. The results also suggest that the weir is not a very efficient sediment trap in this watershed. 相似文献
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《Geoforum》2016
River restoration through dam removal provides an opportunity to investigate the changing nature of environmental conflicts and politics in long-humanized landscapes. In New England, where over 14,000 dams fragment the region’s rivers, dam removals are often highly contested. This is due, in part, to how the intertwined roles of history, identity, and aesthetics coalesce to create attachment to place and inspire the defense of dammed landscapes. Dam removal provides a useful lens to consider the following: How do the historical and geographical contingencies of this region shape and alter conflicts over dam removal in specific ways? In instances where conflicts emerge, what do the conflicts reveal about the politics of ecological restoration in highly altered landscapes? We use a political ecology approach to reveal how complex cultural dynamics, competing interpretations of science and the environment, micropolitics, and the role of multiple actors generate and shape conflicts over dam removal. We show that the historical geography of New England influence conflicts over removal in important ways, particularly with regard to the roles of aesthetics and identity in landscapes that are characterized largely by consumptive as opposed to productive uses. Our findings also suggest that restoration in long-humanized landscapes will embroil new constellations of human and nonhuman actors, requiring attention to the political and cultural, as well as the ecological, dimensions of restoration. This paper contributes to research on the political and social dimensions of dam removal, as well as to research at the nexus of ecological restoration and environmental politics. 相似文献
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