Siltation

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

Impact of Phase III Project of Maji Mountain Port on sediment siltation in adjacent sea area

Abstract: Based on a 3-D Finite Volume Coastal Ocean Model (FVCOM), tidal dynamics has been studied in the sea area around the Phase III Project of Maji Mountain Port (MMP). Furthermore, taking typhoon “Canhong” as an example, a storm surge and sediment model has also been established to study the impact of the Phase III Project on current flows and siltation during extreme weather. Tidal currents before and after the project have been compared. Model results show that the changes of tidal current mainly occur in the engineering areas with a magnitude change of 0.3–0.4 m/s during maximum flood and ebb tides. The flow condition for the port has been improved as the flow direction is changed to parallel to the wharf after the completion of the project. There is little siltation in the adjacent area, which will not affect the safety of ship navigation. Besides, the sudden siltation during typhoon period is relatively weak. The back silting in two days is less than 5 cm indicating no sudden siltation occurs.

Numerical simulations of flow and sediment transport within the Ning-Meng reach of the Yellow River, northern China

Abstract: Effective management of a river reach requires a sound understanding of flow and sediment transport generated by varying natural and artificial runoff conditions. Flow and sediment transport within the Ning-Meng reach of the Yellow River (NMRYR), northern China are controlled by a complex set of factors/processes, mainly including four sets of factors: (1) aeolian sediments from deserts bordering the main stream; (2) inflow of water and sediment from numerous tributaries; (3) impoundment of water by reservoir/hydro-junction; and (4) complex diversion and return of irrigation water. In this study, the 1-D flow & sediment transport model developed by the Yellow River Institute of Hydraulic Research was used to simulate the flow and sediment transport within the NMRYR from 2001 to 2012. All four sets of factors that primarily control the flow and sediment transport mentioned above were considered in this model. Compared to the measured data collected from the hydrological stations along the NMRYR, the simulated flow and sediment transport values were generally acceptable, with relative mean deviation between measured and simulated values of <15%. However, simulated sediment concentration and siltation values within two sub-reaches (i.e., Qingtongxia Reservoir to Bayan Gol Hydrological Station and Bayan Gol Hydrological Station to Toudaoguai Hydrological Station) for some periods exhibited relatively large errors (the relative mean deviations between measured and simulated values of 18% and 25%, respectively). These errors are presumably related to the inability to accurately determine the quantity of aeolian sediment influx to the river reach and the inflow of water from the ten ephemeral tributaries. This study may provide some valuable insights into the numerical simulations of flow and sediment transport in large watersheds and also provide a useful model for the effective management of the NMRYR.

Further studies of the field settling velocities of Thames mud

Abstract: This report describes work undertaken to meet an important need in the successful modelling of siltation processes and prediction of siltation rates. Most previous work on settling of solids from suspension has been laboratory based with little or no attempt to corroborate results in the field. Mr M W Owen developed an appropriate field instrument in 1969 and carried out a limited amount of field measurement, which indicated that settling velocities of cohesive sediments were 10 times higher than previously measured in laboratory tests.

Designing and building gabion check dams in Burkina Faso

Abstract: Gabion check dams (GCDs) are among the most diffused soil and water conservation practices in Burkina Faso, used to cope with soil loss and reservoir siltation. Specifically, CGDs are flexible, permeable structures built in gullies to create a sedimentation bench that decreases the average upstream slope. The consequent slowing-down of the flowing water limits flood-wave sediment transport capacity reducing soil loss upstream, reduces the amount of trapped sediment in reservoirs and promotes water infiltration into the soil. The present work provides concise guidelines for the design and implementation of GCDs in Burkina Faso. This was achieved gathering the experience developed in the frame of several cooperation and development projects led by the Italian non-governmental organization. The theoretical elements and procedural steps to perform an appropriate design and implementation of GCDs are described and discussed, including hydrological and hydraulic methods to assess stream flow characteristics, spillway functioning, siltation rate, dimensions and stability of the structure.

The Connection between a Suspended Sediments and Reservoir Siltation: Empirical Analysis in the Maziarnia Reservoir, Poland

Abstract: This paper presents research on the influence of suspended sediments on selected aspects of a reservoir’s functioning. As the amount of sediment suspended in water (SS) there was found to correlate significantly with sedimentation rate (Us), it was possible to develop a function allowing the rate of accumulation of sediments to be predicted by reference to known amounts of suspended sediment. The latter factor was also shown to correlate significantly with the content of organic matter in suspension (OMSS), in sediment captured in a sediment trap (OMS), and of bottom sediment (OMSB). Analysis of amounts of suspended sediment can provide for estimates of total loads of organic pollutants deposited in the sediments of a reservoir. A further significant correlation with SS was noted for the concentration of total phosphorus in water (TPW), confirming the importance of internal production where the circulation of this biogenic substance in a reservoir ecosystem is concerned. Analysis of stable carbon isotopes in turn showed that entrapped sediments were depleted of—or enriched in—13C, in line with whether concentrations of total P in those sediments (TPS) were at their highest or lowest levels. This dependent relationship may thus be of key importance in assessing sources of phosphorus, as well as in forecasting concentrations present in reservoir sediments. The results obtained make it clear that sediments suspended in the water of a reservoir unify phenomena and processes ongoing there, between elements of the water-sediment system.