Stream and River Water

River water results mainly from two contributions surface runoff of falling rainwater and groundwater upflow. Surface overland runoff is the consequence of precipitation on saturated or impervious surfaces its behavior is cyclical because it depends on the wet and dry spells on Earth. 

On the average, of the nearly 120,000 km3 of rain that fall on land each year, about one-third becomes river runoff. Because of the changing climatic conditions during the last few decades, there has been an increase in river runoff in South America and a decreasing runoff in Africa. 

Organic complex acids Typical color Average formula Average molecular weight 

Fulvic acids (soluble) Light yellow to brown C12H12N0.2O6 1 x 103 

Humic acids (dissolved) Dark brown C10H11N0.3O6 2-5 x 103 

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The army needs a system to clarify medium amounts of stream and river water for drinking, cooking, and washing. The use of aluminum and gravel filtration is not very portable, and an alternative is being sought. You are to demonstrate that gas-assisted flotation will work and will use water from around your area to prove it. In addition you will use a quaternary amine as the surfactant, knowing that any excess will act as a disinfectant in the water. 

Differences in the intensity of management clearly influence the relative concentrations and importance of organic phosphorus, which is reflected in stream and river water. As an example, Christmas and Whitton (1998) reported that filterable organic phosphorus concentrations in the... 

Worman, A. and A.I. Packman. 2002. Effect of flow-induced exchange in hyporheic zones on longitudinal transport of solutes in streams and rivers. Water Resources Research, 38( 1), 2-1-2-15. 

The environmental sampling of waters and wastewaters provides a good illustration of many of the methods used to sample solutions. The chemical composition of surface waters, such as streams, rivers, lakes, estuaries, and oceans, is influenced by flow rate and depth. Rapidly flowing shallow streams and rivers, and shallow (<5 m) lakes are usually well mixed and show little stratification with... 

Because the aminophenols are oxidized easily, they tend to remove oxygen from solutions. Hence, if they are released from industrial waste waters into streams and rivers, they will deplete the capacity of these environments to sustain aquatic life. Concern has also been raised that chlorination of drinking water may enhance the toxicity of aminophenols present as pollutants (138) chlorinated aminophenols are known to be more toxic (139). 

Subsurface runoff. When precipitation hits the land surface, the vast majority does not go directly into the network of streams and rivers in fact, it may be cycled several times before ever reaching a river and the ocean. Instead, most precipitation that is not intercepted by the vegetation canopy and re-evaporated infiltrates into the soil, where it may reside as soil moisture, percolate down to ground-water, or be transpired by plants. 

In most of the world s watercourses, dramatic modifications have occurred as a consequence of their intensive use by human societies [1]. Pollution, water abstraction, riparian simplification, bank alteration, straightening of watercourses, dam construction, and species introduction are widespread perturbations in river ecosystems. These human-driven alterations are part of global changes. The simplification of the channel network and the alteration of water fluxes reduce the capacity of fluvial systems to recover from namral disturbances. Hydrologic alterations affect the functional organisation of streams and rivers, and lead to a simplification and impoverishment of the biota within these ecosystems. 

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. 

Pelletier GJ, Chapra SC, Tao H (2006) QUAL2Kw - a framework for modelling water quality in streams and rivers using a genetic algorithm for calibration. Environ Modell Softw 21 419-425... 

It is desirable to determine the chemical properties of irrigation water, paddy water in the field, and adjacent streams and rivers. Since especially the pH of the paddy water fluctuates diurnally (high in daytime and low at night), this may affect the water solubility of certain chemicals, e.g., sulfonylureas, which have dissociation constants (p/fa) in an environmentally relevant range. 

The Water Cycle. The evaporation of water from land and water surfaces, the transpiration from plants, and the condensation and subsequent precipitation of rain cause a cycle of transportation and redistribution of water, a continuous circulation process known as the hydrologic cycle or water cycle (see Fig. 86). The sun evaporates fresh water from the seas and oceans, leaving impurities and dissolved solids behind when the water vapor cools down, it condenses to form clouds of small droplets that are carried across the surface of the earth as the clouds are moved inland by the wind and are further cooled, larger droplets are formed, and eventually the droplets fall as rain or snow. Some of the rainwater runs into natural underground water reservoirs, but most flows, in streams and rivers, back to the seas and oceans, evaporating as it travels. 

Both nuclear and conventional power plants produce environmentally-sensitive waste. Both use cooling water which when put into streams and rivers while still at elevated temperatures can cause significant damage to the biota. 

For locating these ERWs, the most important characteristic of a body of water is its current. Currents may be nearly nonexistent in some stagnant ponds or irrigated fields. Currents in streams and rivers are usually consistent in direction but variable in velocity. Currents in tidal areas oscillate in direction and vary in velocity. Rapid currents have higher Reynolds numbers, hence more turbulence. Even rather modest velocities in water produce turbulence because the Reynolds number is higher with the higher density than in air. 

The water that falls as rain runs into streams and rivers and then on into lakes, seas and oceans. 

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