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It is common to prepare flow duration curves from a set of daily river flow data, but does it make sense to build a flow duration curve from a set of monthly minimum flow data? I searched on internet, but the key word "minimum flow duration curve" does not return any relevant document.

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    $\begingroup$ What are you trying to determine with the minimum flow duration curve? You can create a flow duration curve on time periods other than daily data (I use 30 min data in one study) but what do you think the minimum monthly data would indicate? Would you do this for just a particular month e.g. minimum June flow? If it tells you something useful then do it and publish it ;-) $\endgroup$ – haresfur Feb 17 '15 at 22:45
  • $\begingroup$ The flow duration curve will naturally show you the trend for low flow values, what you likely want to do is build the FDC and look at the low flow values (i.e. low flow section of the curve) specifically, whether it is built from daily or monthly data. I don't think that building the curve using minimum flow values (daily or monthly) makes sense, although it is an interesting thought. $\endgroup$ – Rob Aug 17 '17 at 14:23
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I believe it is not very useful while FDC's are mostly interesting for the entire discharge record. You can zoom in to the lower part of the curve and analyse it. The problem with the FDC is that it give no indication of sequences of low flows. You can imagine a river with no discharge (=0) during a couple of months for example. With monthly minimum values this problem is smaller.

In the end I believe it's more useful to use probability distributions for frequency analysis of extreme values like low flows. In literature you can find that the Gumbel distribution of the smallest value is one of the most reliable for annual minimum flows.

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