scholarly journals A PRELIMINARY STUDY ON THE EFFECTS OF WATER POLLUTION ON THE RATE OF EVAPORATION FROM THE WATER SURFACE

1972 ◽  
Vol 45 (2) ◽  
pp. 88-92
Author(s):  
Yoshinari AMBE
Keyword(s):  
Water Pollution ◽  
Water Surface ◽  
Preliminary Study ◽  
Rate Of Evaporation

RATE OF EVAPORATION FROM A FREE-WATER SURFACE AS INFLUENCED BY EXPOSURE

1961 ◽  
Vol 41 (1) ◽  
pp. 199-203 ◽  
Author(s):  
A. C. Carder
Keyword(s):  
Water Surface ◽  
Meteorological Factors ◽  
Free Water ◽  
Water Evaporation ◽  
High Wind ◽  
Progressive Decrease ◽  
Factors Affecting ◽  
Wind Velocities ◽  
Rate Of Evaporation ◽  
Low Rate

In a 3-year free-water evaporation study, an evaporimeter tank in the open field lost 34.5 per cent more water than a tank sheltered by buildings and trees. Meteorological factors responsible for this difference appear to be high wind velocities and long daily periods of sunshine. Changes in temperature regime had no effect.Difference in evaporation from the two tanks led to examination of data obtained over 35 years from the sheltered tank. It was found that, although there was a progressive decrease in amount of evaporation over the years from this tank, rainfall at the same time had increased and that the effect of this increase on evaporation was roughly equal to that of all other factors affecting evaporation, such as a change in exposure, etc. Thus, the comparatively low rate of evaporation from the sheltered tank was undoubtedly due in part to the proximity of buildings and trees which had been established.

scholarly journals Some problems connected with evaporation from large expanses of water

1921 ◽  
Vol 99 (701) ◽  
pp. 472-490 ◽  
Keyword(s):  
Vapour Pressure ◽  
Water Surface ◽  
Complex Problem ◽  
Dew Point ◽  
Ice Age ◽  
Trade Wind ◽  
Tropical Regions ◽  
The North ◽  
Rate Of Evaporation ◽  
Large Stretch

1. The water which falls as rain is originally evaporated either from land surfaces, forests, etc., or from the oceans, in particular from the latter. It is therefore of importance to ascertain how the evaporated water distributes itself in an atmospheric current during its progress across a water surface, and, further, to investigate the relation between the length of the path over the water surface and the amount of water thereby rendered available. In this paper, these problems are treated for the case of a current of air of uniform speed moving over a water surface of uniform temperature. An empirical formula is employed to represent the rate of evaporation from each element of the water surface, and account is taken of the stirring upwards of the evaporated water by the agency of turbulence, assuming the latter to be uniformly distributed throughout the current of air. The results obtained would find application, for example, in discussing problems connected with evaporation in the trade wind zones, or from inland seas and lakes, or, in particular, from the North Sea, winds from which frequently bring much cloud and quite appreciable rainfall to the eastern coasts of Great Britain and the northern coasts of France. All the constants occurring in the formulae obtained are known, either accurately or approximately, and, accordingly, the order of magnitude of the evaporation from a given stretch of water, under assigned conditions, can be estimated. What is also of importance, is the comparison of the amount of water evaporated from a given area or of the distribution of water vapour in the air above it, under one set of conditions, with those under a different set. Of particular interest is the effect of varying the speed of the air. 2. The suggestion which led to the present investigation is contained in a paper on “ The Meteorological Conditions of an Ice Sheet and their bearing on the Desiccation of the Globe.” The author of that paper, in considering the evaporation in tropical and sub-tropical regions during the Quaternary Ice Age as compared with that at the present time, has occasion to compare the rate of evaporation from large expanses of water under different conditions as to wind and surface temperature, and Lt. -Col. E. Gold, in the discussion, emphasises the fact that this is in reality a very complex problem for the formula used (quoted below, p. 474) for the rate of evaporation from an element of the surface, involves the vapour pressure at the dew point of the air “ near ” the surface. Now this vapour pressure varies from point to point along the current of air which is traversing the water, so that an integration is necessary in order to obtain the rate of evaporation from a large stretch of water, and, further, the vapour pressure at any point depends on the speed with which the air has reached that point, which complicates the problem of comparing the evaporation under different wind conditions.

The Rate of Evaporation of Water through Duplex Films

1948 ◽  
Vol 1 (2) ◽  
pp. 197 ◽  
Author(s):  
AR Gilby ◽  
E Heymann
Keyword(s):  
Atmospheric Pressure ◽  
Interfacial Layer ◽  
Water Surface ◽  
Complex Nature ◽  
Water Molecules ◽  
Total Evaporation ◽  
Film Evaporation ◽  
Wind Velocities ◽  
Rate Of Evaporation ◽  
The Stability

The stability of duplex films of hydrocarbon oils containing spreaders is discussed in this paper. Duplex films containing spreaders of high molecular weight and of complex nature, e.g. stand oil, eucalyptus residue, polymerized oleic acid, may remain spread for long periods but are thermodynamically metastable. The penetration of water molecules from a water surface through a duplex film has been discussed in terms of the evaporation resistances of the interfacial layer of spreader, the bulk layer of oil and the stagnant layer of air above the film. Evaporation through duplex films of thickness 1-100 μ has been studied in conditions of " still air " at atmospheric pressure and in a vacuum, and in non-turbulent winds at several controlled wind velocities. The efficiency of duplex films in reducing evaporation is greater in wind than in still air and Increases with the wind velocity. When duplex films thicker than 10 μ are placed on water surfaces, even a wind at 8 miles per hour does not increase the rate of evaporation. Thus with such films the resistance of the stagnant layer of air above the film is small compared with that of the oil layer and of the interfacial film of spreader. With all duplex films thicker than 10 μ the total evaporation resistance is proportional to the film thickness and depends on the nature of the spreader. An analysis of the experimental results suggests that the interfacial layer of spreader makes an appreciable contribution to the evaporation resistance of the duplex films under investigation. Approximate relative figures characterizing the magnitude of this contribution are calculated for several spreaders.

STATE JURISDICTION OVER OIL SPILLS IN A FEDERAL SYSTEM

1971 ◽  
Vol 1971 (1) ◽  
pp. 57-67 ◽  
Author(s):  
Daniel Wilkes
Keyword(s):  
Water Pollution ◽  
Pollution Control ◽  
Preventive Measures ◽  
Oil Spills ◽  
Canadian Arctic ◽  
Contingency Planning ◽  
Federal System ◽  
Water Pollution Control ◽  
Federal Water Pollution Control ◽  
Preliminary Study

ABSTRACT A comparison of the bases for state and federal jurisdictions, in the light of Canadian Arctic, Florida, Maine and Federal Water Pollution Control Acts, shows when, how and why state and federal officials will find they have overlapping jurisdictions. The results of this preliminary study point to several areas in which the overlaps should be kept and some key ways in which they may be more rationally related, especially in preventive measures and contingency planning.

Rate of Evaporation from a Free Water Surface by a Perpendicular Air Stream

1938 ◽  
Vol 30 (10) ◽  
pp. 1131-1138 ◽  
Author(s):  
M. C. Molstad ◽  
P. Farevaag ◽  
J. A. Farrell
Keyword(s):  
Water Surface ◽  
Free Water ◽  
Free Water Surface ◽  
Air Stream ◽  
Rate Of Evaporation

Use of constructed wetlands in water pollution control: historical development, present status, and future perspectives

1994 ◽  
Vol 30 (8) ◽  
pp. 209-223 ◽  
Author(s):  
Hans Brix
Keyword(s):  
Water Pollution ◽  
Constructed Wetlands ◽  
Pollution Control ◽  
Historical Development ◽  
Water Surface ◽  
Subsurface Flow ◽  
Free Water ◽  
Water Pollution Control ◽  
Free Water Surface ◽  
Flow Systems

During the last two decades the multiple functions and values of wetlands have been recognized not only by the scientists and managers working with wetlands, but also by the public. The ability of wetlands to transform and store organic matter has been exploited in constructed wetlands. This paper summarizes the state-of-the-art of the uses of constructed wetlands in water pollution control by reviewing the basics of the technology, the historical development, and the performance expectations with focus on the use of free water surface and subsurface flow constructed wetlands for municipal wastewater treatment. Performance data from a total of 104 subsurface flow systems and 70 free water surface flow systems are reviewed. The present state of knowledge is sufficient to apply constructed wetlands as a tool for improving water quality. The potential applications range from secondary treatment of municipal and various types of industrial wastewaters to polishing of tertiary treated waters and diffuse pollution. In many situations constructed wetlands is the only appropriate technology available. The treatment capacity of subsurface flow systems can be improved by selecting vertical flow systems with intermittent loading, by proper media selection, and by recycling of the wastewater. Further research is needed to help define and optimize engineering design criteria and the long-term performance capabilities and operational problems.

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