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- ItemDouble-Mass Curves(1960) Searcy, James K.; Hardison, Clayton H.The double- mass curve is used to check the consistency of many kinds of hydrologic data by comparing date for a single station with that of a pattern composed of the data from several other stations in the area. The double-mass curve can be used to adjust inconsistent precipitation data. The graph of the cumulative data of one variable versus the cumulative data of a related variable is a straight line so long as the relation between the variables is a fixed ratio. Breaks in the double-mass curve of such variables are caused by changes in the relation between the variables. These changes may be due to changes in the method of data collection or to physical changes that affect the relation. Applications of the double-mass curve to precipitation, streamflow, and sediment data, and to precipitation-runoff relations are described . A statistical test for significance of an apparent break in the slope of the double-mass curve is described by an example. Poor correlation between the variables can prevent detection of inconsistencies in a record, but an increase in the length of record tends to offset the effect of poor correlation. The residual-mass, curve which is a modification of the double-mass curve, magnifies imperceptible breaks in the double-mass curve for detailed study. Of the several methods of fitting a smooth curve to cyclic or periodic data, the moving-are method and the double-integration method deserve greater, use in hydrology. Both methods are described in the manual. The moving-arc method has general applicability, and the double integration methods is useful in fitting a curve to cycles of sinusoidal form.
- ItemA Study of the Pollution and Natural Purification of the Ohio River(U.S. Department of Health, Education, & Welfare, 1958) Streeter, H.W.; Phelps, Earle B.
- ItemReservoirs in the United States(U.S. Government Printing Office, 1966) Martin, R.O.R; Hanson, Ronald L.This report summarized the storage capacities and related data of reservoirs and controlled natural lakes for the conterminous United States, Alaska, Hawaii, and the Commonwealth of Puerto Rico. Data are given for all storage facilities having a usable capacity of 5,000 acre-feet or more and completed or under construction as of Jan. 1963. A descriptive list of reservoirs in the United States completed as of Jan. 1, 1947, was first published (Geol. Survey Circular 23) in March 1948. In 1956 Water-Supply Paper 1360-A, "Reservoirs in the United States," by N.O. Thomas and G.E. Harbeck Jr., updated this listing and included lists of reservoirs completed or under construction as of Jan. 1, 1954. Some of the data shown for reservoirs constructed before 1954 may have been corrected herein on the basis of the latest available reservoir survey. This report list 1562 reservoirs and lakes; their useable storage totals 359,360,000 acre-feet, and the corresponding surface area in 14,831,000 acres.
- ItemBiological Implication of Metals in the Environment(Technical Information Center Energy Research and Development Administration, 1977) Drucker, Harvey
- ItemFlow-Duration Curves(1960) Searcy, James K.The flow-duration curve is a cumulative curve that shows the percent of time specified discharges were equaled or exceeded during a given period. It combines in one curve the flow characteristics of a stream throughout the range of discharge, without regard to the sequence of occurrence. If the period upon which the curve is based represents the long-term flow of a stream, the curve may be used to predict the distribution of future flows for waterpower, water-supply, and pollution studies. This report shows that difference in geology affect the low-flow ends of flow-duration curves of streams in adjacent basins. Thus, duration curves are useful in appraising the geologic characteristics of drainage basins. A method for adjusting flow-duration curves of short periods to represent long-term conditions is presented. The adjustment is made by correlating the records of a short-term station with those of a long-term station.