Range of Variability Approach, is introduced in the D. RICHTER 1997 article , "How much water does a river need?" for designing "management targets" for the eco-friendly river management.
My question, is how one can or what are the considerations to design hourly targets based on that approach and those 32 indices he introduced in his seminal 1996 article.
( Should we obtain daily or hourly streamflow records ? but the indices Richter designs targets from are monthly )
Dear Alireza:
Are you referring to hydropeaking? In this case you will need sub-daily data. The hydrologic statistics proposed by Richter are oriented to define environmental flows. For hydropeaking, I suggest you to read the following paper where indexes are proposed to operate reservoirs on sub-daily flow regimes.
Article Characterizing effects of hydropower plants on sub-daily flow regimes
Regards, Alvaro
Dear Dr. Alvaro Sordo-Ward , Thanks for your answer,
Yes, I am looking for designing sub-daily flow requirements. I mentioned the Richter paper because in that they mentioned that the framework is adaptive to management time scales, I was wondering how. When the indexes are monthly one can design sub-daily targets.
I will read the paper you introduced in depth. Thanks for your help.
There are various instream flow methodologies and dependent resources and species. Some of these methodologies require detailed study. Channel maintenance bankfull flows (about 1-2 year storm flow) are needed once every year or two. Maintenance flows help keep vegetation from encroaching on channel and loosing capacity. Fish and other aquatic species may have instream flow needs to maintain their viability and presence. Some apply a minimum flow criteria, such as 7Q10 (the natural minimum weekly average flow that occurs every 10 years). Some flow criteria may be developed for fish spawning, rearing, migration. Other flow criteria set for swimming, dilution of pollution loads, scenic integrity, etc. Fish and aquatic biologists, hydrologists and watershed specialists may help with estimating some of appropriate criteria for situation. Aquatic and riparian habitats also important to many wildlife species. Periodic release of reservoir sediments may be important in maintaining some downstream habitats, point bars, etc. and preventing entrenchment due to clean water releases. There may be many things to consider.
Streamflow and water level correlation are often high, and exponential relationship. If you install recording transducer(s) as backup, you can capture water level changes many times a day. The USGS typically captures flow every 15 minutes. On small flashy catchments, you might go to 5 minute intervals. If flows are pulsing from hydropower. On large rivers at substantialdistance downstream from releases, hourly intervals may be sufficient. Much hydrograph detail is lost if only daily records are considered. Its easy to downsize data, and typically no way to expand it.
Dear Alireza:
I am attaching some studies for operating dams under flood condition and hourly time step:
Article A Parametric Flood Control Method for Dams with Gate-Control...
Chapter Probabilistic methods for hydrologic dam safety analysis
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