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Analysis of an evaporation control system on the sea of Galilee
BOOK REVIEWS
111
The subject matter is divided into parts, each of which covers a major segment of ground-water hydrology. Part I deals with the hydraulic characteristics of rocks, including the nature and the volume of the voids in rocks and their capacity to yield and transmit water. Part II is devoted to the hydraulic characteristics of aquifers - that is, with the characteristics of whole-rock units. In this the reservoir and pipeline functions of aquifers; flow nets; and aquifer boundaries are discussed. Part III, which deals with the field determination of the capacity of aquifers to transmit and store water, introduces the student to some of the concepts and methods used in quantitative studies of ground water. This is to enable the student to move beyond the general description of aquifers and the occurrence of ground water. The effect of the environment on ground water is covered in Part IV. The two chapters in this part deal with the chemical content and the temperature of ground water. The concluding section, Part V, is devoted to syntheses of ground-water information and to the interpretation of maps: the preparation of groundwater maps, the use of topographic and geologic maps and aerial photographs in ground-water investigations, and the methods of water-budget analyses. F.D.
C. O. REISER" Analysis of an Evaporation Control System on the Sea of Galilee. Water Resources Research, Vol. 5, No. 2, April, 1969. Water Planning for Israel is conducting field tests to determine the feasibility of applying long-chain alcohols on the Sea of Galilee for evaporation control reduction. G o o d film covers have been obtained on 280-acre Lake Zohar with winds up to 15 mph, and a spray system is being installed on Lake Kishon to test a larger lake with stronger prevailing winds. Using meteorological data and estimated evaporation rates for the Sea of Galilee, the reduced evaporation when covered with an alcohol film has been calculated from the added film resistance. The iterative solution of an energy balance equating the reduced evaporation energy to increased energy storage, back radiation, and conduction to the atmosphere gave a 40 per cent reduction of the annual evaporation rate of 300 million cubic metres when applying a film for a 10-month period. The film produced a maximum temperature increase of 5 °C at the surface. Since the film is removed by winds at rates of approximately 1/30 of wind speed, effective applications require addition of the material on the windward
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BOOKREVIEWS
shore at rates sufficient to account for all the losses, including wind removal, biological attrition, sublimation and solution. A reduction in the estimated annual evaporation loss of 300 million cubic metres, which is equivalent to nearly a quarter of Israel's present water-usage, could make a significant increase in the country's water supply and materially decrease the salinity of the lake. (From Author's Abs. and text)
Documents on Water Resources, by the U.N. Economic Commission for Africa, Addis Ababa 1. Review of Hydrology in Africa (E/CN.14/INR/17), 1962. 2. Water Supply in Developing African Countries (E/CN.14/INR/21), 1962. 3. Information Note on the United Nations Water Resources Development Decade in Africa (E/CN.14/INR/35), 1963. 4. Notes on the Development of International River Basins in Africa (E/CN.14/INR/38), 1963. 5. Preliminary Views on a Study of Water Legislation in Africa (E/CN. 14/INR/39), 1963. 6. Proposed Water Resources Development Institute for the East African Sub-region. Report of the ECA/Hungarian Mission (ECA internal document, 1966).
111
The subject matter is divided into parts, each of which covers a major segment of ground-water hydrology. Part I deals with the hydraulic characteristics of rocks, including the nature and the volume of the voids in rocks and their capacity to yield and transmit water. Part II is devoted to the hydraulic characteristics of aquifers - that is, with the characteristics of whole-rock units. In this the reservoir and pipeline functions of aquifers; flow nets; and aquifer boundaries are discussed. Part III, which deals with the field determination of the capacity of aquifers to transmit and store water, introduces the student to some of the concepts and methods used in quantitative studies of ground water. This is to enable the student to move beyond the general description of aquifers and the occurrence of ground water. The effect of the environment on ground water is covered in Part IV. The two chapters in this part deal with the chemical content and the temperature of ground water. The concluding section, Part V, is devoted to syntheses of ground-water information and to the interpretation of maps: the preparation of groundwater maps, the use of topographic and geologic maps and aerial photographs in ground-water investigations, and the methods of water-budget analyses. F.D.
C. O. REISER" Analysis of an Evaporation Control System on the Sea of Galilee. Water Resources Research, Vol. 5, No. 2, April, 1969. Water Planning for Israel is conducting field tests to determine the feasibility of applying long-chain alcohols on the Sea of Galilee for evaporation control reduction. G o o d film covers have been obtained on 280-acre Lake Zohar with winds up to 15 mph, and a spray system is being installed on Lake Kishon to test a larger lake with stronger prevailing winds. Using meteorological data and estimated evaporation rates for the Sea of Galilee, the reduced evaporation when covered with an alcohol film has been calculated from the added film resistance. The iterative solution of an energy balance equating the reduced evaporation energy to increased energy storage, back radiation, and conduction to the atmosphere gave a 40 per cent reduction of the annual evaporation rate of 300 million cubic metres when applying a film for a 10-month period. The film produced a maximum temperature increase of 5 °C at the surface. Since the film is removed by winds at rates of approximately 1/30 of wind speed, effective applications require addition of the material on the windward
112
BOOKREVIEWS
shore at rates sufficient to account for all the losses, including wind removal, biological attrition, sublimation and solution. A reduction in the estimated annual evaporation loss of 300 million cubic metres, which is equivalent to nearly a quarter of Israel's present water-usage, could make a significant increase in the country's water supply and materially decrease the salinity of the lake. (From Author's Abs. and text)
Documents on Water Resources, by the U.N. Economic Commission for Africa, Addis Ababa 1. Review of Hydrology in Africa (E/CN.14/INR/17), 1962. 2. Water Supply in Developing African Countries (E/CN.14/INR/21), 1962. 3. Information Note on the United Nations Water Resources Development Decade in Africa (E/CN.14/INR/35), 1963. 4. Notes on the Development of International River Basins in Africa (E/CN.14/INR/38), 1963. 5. Preliminary Views on a Study of Water Legislation in Africa (E/CN. 14/INR/39), 1963. 6. Proposed Water Resources Development Institute for the East African Sub-region. Report of the ECA/Hungarian Mission (ECA internal document, 1966).