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A regional frequency study of extremal rainfall and runoff processes

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The annual maximum daily rainfall and annual maximum flood discharges in Lesotho were subjected to regional analysis. The mean of both time series was found to be a satisfactory parameter for regional study. The nondimensional series generated by using the mean as the divisor rendered the sequences homogeneous in the statistical sense throughout the whole country. The processes in question obey a lognormal probability law and are random in their sequential evolution. The annual maximum daily rainfall does not produce the annual maximum peak discharge in the rivers of Lesotho.

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  1. Adamson P. T., 1979, Probability distributions of best fit to South African flood data, Water SA 5 (2), 70–76.

  2. Box G. E. P. and Jenkins G. M., 1976, Time Series Analysis; Forecasting and Control, Holden-Day, San Francisco, pp. 289–291.

  3. Cunnane C., 1975, Flood estimations by statistical methods, Flood Studies Conference, Institution of Civil Engineers, London, pp. 43–46.

  4. Cunnane C., 1978, Unbiased plotting position—a review, J. Hydrol. 37, 205–222.

  5. Cunnane C., 1985, Factors affecting choice of distributions for flood series, Hydrol. Sci. J. 30(1, 3), 25–36.

  6. Freund J. E., 1971, Mathematical Statistics, Prentice-Hall, Englewood Cliffs, pp. 395–397.

  7. Kite G. W., 1975, Confidence limits for design events, Water Resour. Res. 11, 48–53.

  8. Linsley R. K., Kohler M. A., and Paulhus J. L. H., 1982, Hydrology for Engineers, McGraw-Hill, Tokyo, Japan, pp. 368–369.

  9. Srikanthan R. and McMahon T. A., 1981, Log Pearson III distribution—an empirically derived plotting position, J. Hydrol. 5, 161–163.

  10. Yevjevich V., 1972, Probability and Statistics in Hydrology, Water Resources Publications, Fort Collins, Col., pp. 186–224.

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Sharma, T.C., Makhoalibe, S. A regional frequency study of extremal rainfall and runoff processes. Water Resour Manage 1, 223–235 (1987). https://doi.org/10.1007/BF00429944

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Key words

  • Annual maximum daily rainfall
  • annual maximum flood
  • lognormal probability
  • moment ratio diagram
  • autocorrelation
  • analysis of variance
  • regionalisation