River system

C. D. Becker and D. A. Neitzel, eds.. Water Quality in North American River Systems, BatteUe, Columbus, Ohio, 1992. 

L. Bowling, The Cyanobacterial (Bine-Green Algal) Bloom in the DarlingJBarwon River System,... 

Finally, in this Introduction, it is worthwhile to reproduce one of the several current definitions, in the Oxford English Dictionary, of the word simulate To imitate the conditions or behaviour of (a situation or process) by means of a model, especially for the purpose of study or training specifically, to produce a computer model of (a process) . The Dictionary quotes this early (1958) passage from a text on high-speed data processing A computer can simulate a warehouse, a factory, an oil refinery, or a river system, and if due regard is paid to detail the imitation can be very exact . Clearly, in 1958 the scientific uses of computer simulation were not yet thought worthy of mention, or perhaps the authors did not know about them. 

The second type of hydroelectric plant is called a run-of-the-nver system. In this case, the force of the river current applies pressure to the turbine blades to produce electricity. Run-of-the-river systems do not usually have reseiwoirs and cannot store substantial quantities of water. As a result, power production from this type of system depends on the river flow— the electricity supply is highly dependent upon seasonal fluctuations in output. Run-of-river projects are most successful when there are large flows in flat rivers or when a high natural geological drop is present, and when the required electricity output is below the maxiniuiii potential of the site. 

The basis for assessment of river quality is valid data, but the question of data validity is secondary to the fundamental question What is the purpose of the river quality assessment activity What questions are being asked In short the means are determined by the ends. If, for example, the intent of an assessment program is to ascertain compliance with law, then a fixed interval "grab sampling program could be established at various river system sites selected on the basis of established guidelines which are consistent with the... 

Nitrification as a deoxygenation process is normally significant only in river systems receiving pollutional inputs of ammonia. The kinetics of nitrification are less clear than those for carbonaceous deoxygenation (33). 

Atmospheric Reaeration. Interfacial properties and phenomena that govern oxygen concentrations in river systems include 1) oxygen solubility (temperature, partial pressure and surface dependency), 2) rate of dissolution of oxygen (saturation level, temperature and surface thin film dependency, i.e., ice, wind), and 3) transport of oxygen via mixing and molecular diffusion. A number of field and empirically derived mathematical relationships have been developed to describe these processes and phenomena, the most common of which is (32) ... 

The following chapter is a case study of how the three problem areas illustrated (dissolved oxygen depletion, erosion/deposition, and potentially toxic trace elements) may be successfully addressed on a major river system using quantitative, semi-quantitative and qualitative approaches respectively. 

The travel time for suspended load is controlled by the flow velocity and the distance to the basin outlet. Flow velocities do not change much downstream in a typical river system (Leopold, 1953) and typically range from 0.1 to several m/s. Hence, suspended load should be able to travel at least 10 to 100 km per day and the travel time for suspended sediment to traverse even the longest rivers in the world should be less than a season. Although some of the suspended load will be deposited in floodplains, the component of the suspended load that does not get sequestered in terrestrial depositional environments is delivered almost as fast as the water that it flows in. Bedload travels much more slowly. In mountain drainage basins, the velocity of individual bedload clasts is on the... 

Franzinelli, E. and Potter, P. E. (1983). Petrology, chemistry, and texture of modem river sands, Amazon River system. /. Geol. 91, 23-39. 

Gibbs, R. J. (1967). The geochemistry of the Amazon River system Part 1, The factors that control the salinity and composition and concentration of suspended solids. Geol. Soc. Am. Bull. 78,1203-1232. 

Koehnken, L. (1990). The composition of fine-grained weathering products in a large tropical river system, and the transport of metals in fine-grained sediments in a temperate estuary, Ph.D. thesis, Princeton University, Department of Geological and Geophysical Sciences. 

Stallard, R. F. (1980). Major element geochemistry of the Amazon River system. Ph.D. Dissertation, Massachusetts Institute of Technology/Woods Hole Oceanographic Institution, Joint Program in Oceanography, Woods Hole Oceanographic Institution Woods Hole, MA WHOI-80-29. 

Stallard, R. F., Koehnken, L., and Johnsson, M. J. (1991). Weathering processes and the composition of inorganic material transported through the Orinoco River system, Venezuela and Colombia. Geoderma 51,133-165. 

Referring to the discussion of the fundamental concepts regarding half cells and the Nernst equation in Chapter 5 (Section 5.3.1) it is possible to briefly summarize the similarities and differences of these two sets of systems. It is important to recognize the ways in which they are different when considering the behavior of complex multivariate systems such as the oceans and clouds, or a lake-river system. 

Disturbances that increase water scarcity promote the physical uniformity of river systems and the decrease of biological diversity in streams and rivers. The structure and functioning of heavily impacted river systems become mutually and strikingly similar, irrespective of the river s origin and the climate. The more intense and persistent the disturbance, the greater is the resemblance. On the other hand, river organisms use resources most efficiently in spatially heterogeneous chaimels, and under moderate disturbance frequencies, rather than in steady conditions, to which they are not adapted. 

Nilsson C, Reidy CA, Dynesius M et al (2005) Fragmentation and flow regulation of the world s large river systems. Science 308 405 08... 

Dynesius M, Nilsson C (1994) Fragmentation and flow regulation of river systems in the Northern third of the World. Science 266 753-762... 

Hamilton SK, Bunn SE, Thoms MC et al (2005) Persistence of aquatic refugia between flow pulses in a dryland river system (Cooper Creek, Australia). Lirrmol Oceanogr 50 743-754 Bernal S, Butturini A, Sabater E (2002) Variability of DOC and nitrate responses to storms in a small Mediterranean forested catchment. Hydrol Earth Syst Sci 6 1031-1041 Romani AM, Vazquez E, Butturini A (2006) Microbial availability and size fractionation of dissolved organic carbon after drought in an intermittent stream biogeochemical link across the Stream-Riparian interface. Microb Ecol 52 501-512... 

Brion N, Billen G (2000) Wastewater as a source of nitrifying bacteria in river systems the case of the River Seine downstream from Paris. Water Res 34 3213-3221... 

An analysis of the EPA STORET Data Base (1980-1982) found that trichloroethylene had been positively detected in 28% of 9,295 surface water reporting stations nationwide (Staples et al. 1985). An analysis of 1,350 samples taken from 1978 to 1979 and 4,972 samples from 1980 to 1981 from the Ohio River system found a similar percentage of positive detections most positive samples had trichloroethylene levels of... 

Parks J, Hamilton A. 1987. Accelerating the recovery of the mercury contaminated Wabigoon English River system. Hydrobiologia 149 159-188. 

Rudd JWM, Turner MA, Furutani A, Swick AL, Townsend BE. 1983. The English-Wabigoon River system. I. A synthesis of recent research with a view towards mercury amelioration. Can J Fish Aquat Sci 40 2206-2217. 

More recently, Henry et al. (2002) have applied this same profile approach to dorrble-crested cormorants, snowy egrets, and black-crowned night herons from the Carson River system, demonstrating its across-species applicability. Hermy and coworkers expanded the profile to include histopathological parameters. 

Moore DG, Edmond (1984) Radium and barium in the Amazon River system. J Geophys Res 89 2061-... 

Sanchez F, Rodriguez-Alavarez MJ (1999) Effect of pH, conductivity and sediment size on thorium and radium activities along Jucar River (Spain). J Radioanal Nucl Chem 242 671-681 Sarin MM, Krishnaswami S, Somayajulu BLK, Moore WS (1990) Chemistry of U, Th, and Ra isotopes in the Ganga-Brahmaputra river system Weathering processes and fluxes to the bay of Bengal. Geochim Cosmochim Acta 54 1387-1396... 

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