Geological Survey Water-supply Paper

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U.S. Government Printing Office, 1950 - Irrigation

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Page 7 - Time-weighted average is computed by multiplying the number of days in the sampling period by the concentrations of individual constituents for the corresponding period and dividing the sum of the products by the total number of days. A time-weighted average represents the composition of water that would be contained in a vessel or reservoir that had received equal quantities of water from the...
Page 8 - The mineral constituents and physical properties of natural waters reported in the tables of analyses include those that have a practical bearing on the value, of the waters for most purposes. The analyses generally include...
Page 10 - Magnesium (Mg) Magnesium is dissolved from many rocks, particularly from dolomitic rocks. Its effect in water is similar to that of calcium. The magnesium in soft waters may amount to only 1 or 2...
Page 18 - Grande and the industrial application of water analyses, 1911. •339. Quality of the surface waters of Washington, 1914. *363. Quality of the surface waters of Oregon, 1914. *418. Mineral springs of Alaska, with a chapter on the chemical character of some surface waters of Alaska, 1917.
Page 14 - It is commonly recognized by the increased quantity of soap required to produce lather. The use of hard water is also objectionable because it contributes to the formation of scale in boilers, water heaters, radiators, and pipes, with the resultant decrease in rate of heat transfer, possibility of boiler failure, and loss of flow.
Page 17 - River drainage basin, with an introductory chapter on physiographic features, 1904. *161. Quality of water in the upper Ohio River basin and at Erie, Pa.
Page 10 - Natural wa ters that contain only 3 or 4 parts per million of the two together are likely to carry almost as much potassium as sodium. As the total quantity of these constituents increases, the proportion of sodium becomes much greater.
Page 10 - As the total quantity of these constituents increases, the proportion of sodium becomes much greater. Moderate quantities of sodium and potassium have little effect on the usefulness of the water for most purposes, but waters that carry more than 50 or 100 parts per million of the two may require careful operation of steam boilers to prevent foaming. More highly mineralized waters that contain a large proportion of sodium salts may be unsatisfactory for irrigation.
Page 12 - Fluoride in water is known to be associated with the dental defect known as mottled enamel, if the water is used for drinking by young children during calcification or formation of the teeth. This condition becomes more noticeable as the quantity of fluoride in water increases above 1 part per million.
Page 8 - The quantity of dissolved mineral matter in a natural water depends primarily on the type of rocks or soils with which the water has been in contact and the length of time of contact.

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