Siltation

About: Siltation is a research topic. Over the lifetime, 1420 publications have been published within this topic receiving 20983 citations.

Mining Pollution: the Case of the Baguio Mining District, the Philippines

Abstract: Environmental problems caused by improper mine tailings disposal in the Baguio district include pollution of the Lower Agno River system and its watershed and siltation of irrigation canals in the Pangasinan plains. Direct economic losses are from reduced agricultural production due to siltation of irrigation works and farmlands. To check the adverse ecological effects of improper mine tailings disposal, government regulations have been imposed on mining firms. Several disposal schemes have been proposed, including the use of the reservoir of a multipurpose project to be sited in the watershed where the mines are located. Because of siltation problems, however, trapping the tailings in the reservoir will diminish the economic benefits that can be derived from the project.

Impact of urbanization on the sediment yield in tropical watershed using temporal land-use changes and a GIS-based model

Abstract: Abundant rainfall areas promote sediment yield at both sub-watershed and watershed scale due to soil erosion and increase siltation of river channel, but it can be curtailed through planned urbanization. The urbanization of Skudai watershed is analysed from historical and future perspective. A GIS-based model (Hydrological Simulation Programme-FORTRAN-HSPF) is used to modelled sediment flow using basin-wide simulation, and the output result is utilized in evaluating sediment yield reduction due to increased urbanization by swapping multiple temporal land-use of decadent time-steps. The analysis indicates that sediment yield reduces with increase urban built-up and decrease forest and agricultural land. An estimated 12 400 tons of sediment will be reduced for every 27% increase in built-up areas under high rainfall condition and 1 490 tons at low rainfall. The sensitivity analysis of land-use classes shows that built-up, forest and barren are more sensitive to sediment yield reduction compared to wetland and agricultural land at both high and low rainfall. The result of the study suggests that increased urbanization reduced sediment yield in proportion to the rainfall condition and can be used as an alternative approach for soil conservation at watershed scale independent of climate condition.

Complex Sediment Transport Pattern on a Spit-Platform in the Danish Wadden Sea

Abstract: Spit-platforms have not drawn much attention, despite their expected importance for understanding sediment transport mechanisms leading to siltation of tidal channels. In this article, the complex sediment transport pattern on a shallow spit-platform in the Danish Wadden Sea is described based on measurements from four current meters deployed on the spit-platform in a low- and a high-energy period. The hydrodynamic characteristics at the four stations are different in terms of impact from tidal and wave-induced currents. The sediment enters the spit-platform as sandbars oriented perpendicular to the shore migrating alongshore, because of wave activity, until the sediment reaches an ebb-dominated tidal channel. In and near this channel, the sediment is transported downdrift by the ebb-tidal currents until the sand enters a shallow dissecting ebb channel, where the sand is transported obliquely offshore and deposited on a small ebb-tidal delta. This zigzag pattern of sediment transport continues un...

Management of watersheds and water resources planning

Abstract: Siltation of reservoirs is a consequence of poor management of watersheds. Four case studies have been highlighted in this study to indicate the reasons for increased siltation, such as population growth, deforestation, extensive agricultural operations, cattle grazing and soil erosion. Nizamsagar and Sriramsagar are reservoirs heavily silted due to lack of proper management practices in the watershed. Machkund and Tungabhadra are reservoirs in which siltation has been contained through systematic management of the watersheds. Procedures needed for managing watersheds in water resources projects have been derived based on the four case studies

Grain size distribution and transportation trends of bottom sediments in the sand ridge field of the south yellow sea,china

Abstract: Grain size distribution and end-member-modeling algorithm analysis(EMMA) were conducted for the 117 bottom sediments taken from the radial sand ridge field(RSRF) of the South Yellow SeaSediment sources,transportation pattern and topography changes as well as the shifting of boundaries of the Yellow and Changjiang Rivers and their sediments diffusion pattern were studied for revealing the evolutionary trend of the radial sand ridge field and the siltation potential of the tidal flatsThe RSRF region is dominated by silt and sand,though there is distinguished lateral variationThere occur silty materials in the subaqueous delta of the abandoned Yellow River,sandy silts in the northern RSRF,silty sands in the central RSRF,fine sands in the radial sand ridges,and more silty materials in the southern RSRFThe results of EMMA reveal that coarse silts from the Abandoned Yellow River Subaqueous Delta(AYRSD) and the Changjiang River have a significant effect on the bottom sediments of the RSRFThe fine materials from the AYRSD have been transported southwards and northeastwards,and the fine materials from the Changjiang River delta transported northwards,whereas the fine sands in the central RSRF have been transported southwards up to the foreshore areaCompared with the samples recovered from the RSRF during the surveys in 1980s and 1990s,fine materials in the whole study area are reduced and the sediments getting coarser as the result,showing an obvious trend of erosion