Reservoirs sedimentation

Reservoir sedimentation data allow estimating sediment loads of regulated catchments, although it is important to note that this sedimentation represents a fraction of the true yield since reservoir sediment trapping efficiency is usually... 

Wright, J.F., Dallimore, S.R., Nixon, F.M., Duchesne, C. 2005. In situ stability of gas hydrate in reservoir sediments of the JAPEX/JNOC/GSC et al. Mallik 5L-38 gas hydrate production research well. Geological Survey of Canada, Bulletin 585. 

Wastes generated by mining and milling released these metal sulfides as particulate substances (i). Mixed with uncontaminated sediment in the river system, these particulate wastes moved hundreds of kilometers downstream from their original source (4-7). Channel, floodplains, and reservoir sediments throughout the river now contain much of this contamination. 

Fine-grained reservoir sediments Interlayered silt, sand, gravel Coarse-grained sand and gravel Low-conductivity Belt metasediments... 

All of these reactions are partially or strongly controlled by bacterial interaction. These reactions develop a general vertical zonation of oxic, anoxic sulfidic, and anoxic methanic environments (13) within the reservoir sediment (Figure 7) that migrates with the rise and fall of the reservoir stage. This fluctuation develops a redox pump that mobilizes contaminants with each successive stage cycle. 

In Milltown Reservoir sediments and other metal sulfide contaminated systems (18), FeS2 (pyrite) in this reaction can be replaced by any number of other metal sulfides (for example, arsenopyrite, chalcocite, galena, and... 

Johns, C. Moore, J. N. Trace Metals in Reservoir Sediments of the Lower Clark Fork River, Montana Montana Water Resources Research Center Bozeman, MT, 1986. 

Lake Superior, Duluth, Minnesota and Superior, Wisconsin harbors, USA Lake Superior, Great Lakes, North America Lake SuRer See, Germany sediment core Lake Waco (Reservoir) sediments, Texas, USA 48 samples... 

Abraham, J. (1998) Spatial distribution of major and trace elements in shallow reservoir sediments an example from Lake Waco, Texas. Environmental Geology, 36(3-4), 349-63. 

Christensen, V.G. and Juracek, K.E. (2001) Variability of metals in reservoir sediment from two adjacent basins in the central Great Plains. Environmental Geology, 40(4-5), 470-81. 

Kneebone, P.E., O Day, P.A., Jones, N. and Hering, J.G. (2002) Deposition and fate of arsenic in iron- and arsenic-enriched reservoir sediments. Environmental Science and Technology, 36(3), 381-86. 

In these examples as well as for most aquatic sediments, the principal diagenetic reactions that occur in these sediments are aerobic respiration and the reduction of Mn and Fe oxides. Under the slower sedimentation conditions in natural lakes and estuaries, there is sufficient time (years) for particulate organic matter to decompose and create a diagenetic environment where metal oxides may not be stable. When faster sedimentation prevails, such as in reservoirs, there is less time (months) for bacteria to perform their metabohc functions due to the fact that the organisms do not occupy a sediment layer for any length of time before a new sediment is added (Callender, 2000). Also, sedimentary organic matter in reservoir sediments is considerably more recalcitrant than that in natural lacustrine and estuarine sediments as reservoirs receive more terrestrial organic matter (Callender, 2000). 

In general, reservoir sediments can be dated by several techniques. In one technique, the sediment surface is dated by the time of coring while in the other the date is derived from a visual inspection of the cored sediment column which often penetrates the pre-impoundment surface. The primary... 

In natural lacustrine and slowly-accumulating reservoir sediments, core dating with the isotope °Pb has been used extensively (Schell and Earner, 1986). Appleby and Oldfield (1983) found that the constant rate of °Pb supply model (CRS) provides a reasonably accurate sedimentation chronology. The basic assumption of the CRS model is that the rate of supply of excess °Pb to the lake is constant. This model, thus, assumes that the erosive processes in the catchment are steady and give rise to a constant rate of sediment accumulation (MAR) (Appleby and Oldfield, 1983). In practice, for reservoirs, this assumption is rarely met because, for example, an increase in the MAR caused by land disturbances, such as those associated with the urban development, transports additional surficial soils and sediments to the lake. This additional erosion increases the MAR and also increases the rate of supply of °Pb to the lake. In general, because excess °Pb is an atmospheric fallout radionuclide, the model works better in low sedimentation rate, atmospherically dominated lakes with undisturbed watersheds, than in high sedimentation rate, fluvially dominated urban lakes and reservoirs. 

Another problem with age dating of reservoir sediment is the concept of sediment focusing. This concept was developed to correct for... 

Figure 9 (a) Temporal distribution of total sedimentary zinc in US reservoir sediment cores, (b) regression of... 

Run Reservoir, Southwestern West Virginia, USA (b) Temporal distribution of Ti-normaUzed S-IRM-Fe (wt.%/wt.%) in the Mile Tree Run Reservoir sediment core. 

Figure 14 (a) Scatter plot of Appalachian Basin temporal coal production versus temporal concentration of Zn in a Mile Tree Run Reservoir sediment core, (b) Scatter plot of the temporal concentration of IRM (magnetite) versus the temporal concentration of Zn in the Mile Tree Run Reservoir sediment core. 

Callender E. and Van Metre P. C. (1997) Reservoir sediment cores show US lead declines. Environ. Sci. Technol. 31, 424A-428A. 

Ritchie J. C., McHenry J. R., and Gill A. C. (1973) Dating recent reservoir sediments. Limnol. Oceanogr. 18, 254-263. 

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