River flow

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 power spectra S(f) for transport phenomena in many diverse physical systems including transistors, superconductors, highway traffic and river flow ([bak88a],[carl90]) - has been experimentally observed to diverge at low frequencies with a power law f, with 0.8 < (3 < 1.4, Moreover, S f) obeys this power-law behavior over very large time scales. Commonly referred to as the l//-noise (or Bicker-noise noise) problem, there is currently no general theory that adequately explains the ubiquitous nature of 1/f noise. 

Rivers flowing into the Lagoon (the Brenta, Bacchiglione, Dese, Sile, and Piave) were progressively silting up large areas. At the same time, the... 

Though extremes are part of the normal hydrologic behaviour in Mediterranean-type rivers, a consistent trend of water flow decrease has been described in many of these systems. The Ebro is the largest Iberian river flowing into the Mediterranean Sea. The flow records at its mouth (mean annual runoff 13,408 Mm ) show a decrease of nearly 40% in mean annual flow in the last 50 years. The forces behind these flow decreases are multiple. Higher water withdrawal, climate change and... 

Werritty A (2002) Living with uncertainty climate change, river flows and water resource management in Scotland. Sci Total Environ 294 29 0... 

Topaloglu F (2006) Regional trend detection of Turkish river flow. Nord Hydrol 37 165-182... 

Another manifestation of climate warming can be seen in the timing and volume of spring runoff from the Sacramento River [4, 33]. River flows are peaking earlier in the year compared to the early twentieth century (about 3 weeks earlier on... 

Minutes/hours for example, storms affecting sewer systems, punctual discharges, river flow rate variations due to hydroelectric plants, residence time in a WWTP, etc. 

Days/weeks for example, algal growth, variations of water demand, news on newspapers, residence time in a river flow, etc. 

In the case of river streams, the effect of dispersing the oil creates a strong peak of pollution running along the river flow. The living organisms are submitted to short-term but intense pollution, leading to acute effects. 

River inputs. The riverine endmember is most often highly variable. Fluctuations of the chemical signature of river water discharging into an estuary are clearly critical to determine the effects of estuarine mixing. The characteristics of U- and Th-series nuclides in rivers are reviewed most recently by Chabaux et al. (2003). Important factors include the major element composition, the characteristics and concentrations of particular constituents that can complex or adsorb U- and Th-series nuclides, such as organic ligands, particles or colloids. River flow rates clearly will also have an effect on the rates and patterns of mixing in the estuary (Ponter et al. 1990 Shiller and Boyle 1991). 

Electric current, which is the flow of electrons, is in many ways directly analogous to the flow of water. Think of a river flowing over a waterfall. The volume of water flowing past a point in the river each second is analogous to electrical current, and the height of the waterfall is analogous to a voltage drop. 

A worst-case scenario for delivery of pollutant to the Mississippi River would entail the assumptions that (1) The rainfall on all lagoons becomes saturated with the contaminant (2) all contaminated rainwater reaches the river, and (3) characteristic river flow is at an historic low. 

Insertion of values for area, rain, and river flow,converted to a consistent unit basis, yields... 

Fig. 4 GREAT-ER - refinement of generic regional exposure models, by taking into consideration actual discharge pathway, river flow and waste water treatment plant (WWTP) (as described...

GREAT-ER system the required river flow distributions, flow velocities and river characteristics. 

At the medium reach, the river flows into the Iberian Depression, with marl and gypsum Miocene deposits in some areas. The dissolution of evaporitic sediments (gypsum, halite, and sodium-sulfates) gives rise to numerous sinkholes. However, subsidence is also being masked by morpho-sedimentary dynamic processes such as aggradation and erosion [12]. 

Xu C (1999) From GCMs to river flow a review of downscaling methods and hydrologic modelling approaches. Prog Phys Geogr 23(2) 229-249. doi 10.1177/030913339902300204... 

Fowler HJ, Kilsby CG (2007) Using regional climate model data to simulate historical and future river flows in northwest England. Clim Change 80 337-367... 

Nash JE, Sutcliffe JV (1970) River flow forecasting through conceptual models part I - a discussion of principles. J Hydrol 10(3) 282-290... 

The summer pattern of circulation with the Segre River flowing above the Ebro River water has been pointed as providing optimal epilimnetic conditions for the growth of the zebra mussel [40]. 

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