SampleLmoments: \(l_1, l_2, t_3, t_4\) from unbiased
probability-weighted moments (Hosking 1990), as lmom::samlmu.
FloodFrequency: T-year floods \(F^{-1}(1 - 1/T)\) of annual
maxima by GEV or Gumbel L-moment fits (GEV shape by Hosking's rational
approximations, as lmom::pelgev) or Bulletin 17B log-Pearson III
(moments of \(\log_{10} Q\), bias-corrected skew).
LowFlowFrequency: the d-day, T-year low flow from
annual minima of the d-day moving mean, by the three-parameter
Weibull (L-moments, as lmom::pelwei) or log-Pearson III.
FlowDurationCurve: descending flows against exceedance
\(i / (n + 1)\), with interpolated quantiles. Identical to the Python arm
morie.fn.hydro.
Usage
SampleLmoments(x)
FloodFrequency(amax, dist = "gev", return_periods = c(2, 5, 10, 25, 50, 100))
LowFlowFrequency(flows, years, d = 7L, T = 10, dist = "weibull")
FlowDurationCurve(flows, probs = NULL)References
Hosking, J. R. M. and Wallis, J. R. (1997). Regional Frequency Analysis: An Approach Based on L-Moments. Cambridge University Press.
Interagency Advisory Committee on Water Data (1982). Guidelines for Determining Flood Flow Frequency, Bulletin 17B. USGS.
Vogel, R. M. and Fennessey, N. M. (1994). Flow-duration curves. I: New interpretation and confidence intervals. Journal of Water Resources Planning and Management 120, 485-504.