Man-made reservoirs

Reservoirs can be either natural or man-made. Natural reservoirs can include lakes or other contained water bodies, while man-made reservoirs usually consist of some sort of engineered structure, such as a tank or other impoundment structure. In addition to the water containment structure itself, reservoir systems may also include associated water treatment and distribution equipment, including intakes, pumps, pump houses, piping systems, chemical treatment and chemical storage areas, and so forth. 

Retaining river water within man-made reservoirs also can affect water quality. For example, reservoir retention of silicate-rich river water can lead to diatom blooms within the man-made lakes and thus depletion of silicate within the river water. One result is that increased ratios of dissolved nitrate and phosphate to dissolved silica may have helped change primary production in coastal areas from diatom-based to dinoflagellates and coccolithophor-ids. One result of this altered production may be increased hypoxia in coastal and shelf waters in the north-western Black Sea and other areas off large rivers. 

As a specific example, consider oceanic sulfate as the reservoir. Its main source is river runoff (pre-industrial value 100 Tg S/yr) and the sink is probably incorporation into the lithosphere by hydrogeothermal circulation in mid-ocean ridges (100 Tg S/yr, McDuff and Morel, 1980). This is discussed more fully in Chapter 13. The content of sulfate in the oceans is about 1.3 X lO TgS. If we make the (im-realistic) assumption that the present runoff, which due to man-made activities has increased to 200 Tg S/yr, would continue indefinitely, how fast would the sulfate concentration in the ocean adjust to a new equilibrium value The time scale characterizing the adjustment would be To 1.3 X 10 Tg/(10 Tg/yr) 10 years and the new equilibrium concentration eventually approached would be twice the original value. A more detailed treatment of a similar problem can be found in Southam and Hay (1976). 

Studies have indicated that large-scale storage could take place with gaseous hydrogen underground in aquifers, depleted petroleum or natural gas reservoirs or man made caverns from mining operations. One of... 

The release of man-made CFCs in the atmosphere has lead to an increase of chlorine containing reservoir molecules such as CIONO, (chlorine nitrate) and HC1 in the stratosphere. Under normal nonpolar conditions, the reaction between both species is extremenly slow. However in the presence of cold surfaces, the following reactions are believed to occur on the PSCs [33] ... 

Unlike storage in reservoirs or aquifers which rely on natural voids in porous and permeable rocks, with storage in salt caverns, the gas is stored in man-made, solution-mined caverns. Geology is only the starting point, and engineers design and construct the project. 

The sample is exploded under water (in a natural water reservoir or in a man-made pool), and the pressure of the resulting impact wave is measured with the aid of lead or copper membranes. 

Experimental measurements have determined the great speed of development of gas anomalies over man-made underground gas reservoirs. 

Another means to reduce man-made carbon dioxide emissions is sequestration in the land or the ocean. When carbon dioxide is produced locally it may be possible to efficiently separate it from other gases, concentrate it, and dispose of it. A number of complex scenarios may be envisioned to accomplish this disposal, from pumping it into the ocean, to displacing methane in coal mines, to storage in depleted hydrocarbon reservoirs. 

It should be mentioned that only about the half of anthropogenic C02 remained airborne in the past decades.4 However, this does not necessarily mean that the fraction of man-made C02 stored in the atmosphere will always be the same in the future. For this reason it is essential to determine from past variations the factors governing the fate of anthropogenic carbon dioxide. It is also essential to include these factors in so-called reservoir or box models5 to calculate, on the one hand, the fraction absorbed by oceans and, on the other hand, the part of the emission used by the land biota. Since the uptake of carbon dioxide by ocean waters is governed by more or less known physical and chemical laws the response of land plants to the increase of C02 level, which is much more complicated, can be estimated by difference between total C02 input and oceanic absorption (e.g. Keeling, 1973). 

All fractures generated by internal fluid overpressure are here referred to as hydrofractures. The fracture-generating fluid may be oil, gas, magma, groundwater, or geothermal water. Hydrofractures include dykes, inclined sheets, mineral veins, many joints, and the man-made hydraulic fractures that are used in the petroleum industry to increase the permeability of reservoir rocks. Hydrofractures are primarily extension fractures (Gudmundsson et al. 2001). The difference between the total fluid pressure in a hydrofracture and the normal stress, which for extension fractures is the minimum compressive principal stress, oj, is referred to as the fluid overpressure. 

Optimal periodic control involves a periodic process, which is characterized by a repetition of its state over a fixed time period. Examples from nature include the circadian rhythm of the core body temperature of mammals and the cycle of seasons. Man-made processes are run periodically by enforcing periodic control inputs such as periodic feed rate to a chemical reactor or cyclical injection of steam to heavy oil reservoirs inside the earth s crust. The motivation is to obtain performance that would be better than that imder optimal steady state conditions. 

The chemical composition of air depends on the natural and man-made sources of the constituents (their distribution and source strength in time and space) as well the physical (e. g. radiation, temperature, humidity, wind) and chemical conditions (other trace species) which determine transportation and transformation. Thus, atmospheric chemistry is not a pure chemistry and also includes other disciplines which are important for describing the interaction between atmosphere and other surrounding reservoirs (biosphere, hydrosphere, etc.). Measurements of chemical and physical parameters in air will always contain a geographical component, i. e., the particularities of the locality. That is why the terms chemical weather and chemical climate have been introduced. For example, diurnal variation of the concentration of a substance may occur for different reasons. Therefore general conclusions or transfer of results to other sites should be done with care. On the other hand, it is a basic task in atmospheric chemistry not only to present local results of chemical composition and its variation in time, but also to find general relationships between pollutants and their behavior under different conditions. 

Developing technologies for CO2 extraction from natural reservoirs (ambient air, seawater) to achieve a global man-made carbon cycle while allowing CO2 emissions into the atmosphere from mobile and small sources ... 

The Reservoir At elevation 1221.4, Lake Mead, Ae largest man-made lake m Ae United States, contains 28,537,000 acre-feet (an acre-foot is Ae amount of water required to cover 1 acre to a depA of 1 foot). This reservoir will store Ae entire average flow of Ae river fi>r two years. That muA water would cover Ae enAe state of Peimsylvania to a depA of 1 ft. 

The coo Ii ng funct ion of this UHS system can be provided by cooling towers or the natural or man-made passive water sources (e.g., reservoirs, rivers or lakes). For the case of cooling towers, the structure should be designed to withstand the effects of natural phenomena including tornadoes, tornado missiles, hurricane winds, floods, and the design basis earthquake. 

Human activities can affect this water cycle. Cutting vegetation can increase the rate of runoff, causing less water to become absorbed into the soil. Man-made dams and reservoirs increase the surface area available for water evaporation. Using more groundwater than can be replenished may deplete the aquifers and lead to water shortages. And society can contaminate the water in a wide variety of ways that 1 discuss in this chapter. 

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