Generally, to maintain ecological status, five factors are considered for a river ecosystem:
1. flowing water that is mostly unidirectional
2. a state of continuous physical change
3. many different (and changing) microhabitats
4. variability in the flow rates of water
5. plants and animals that have adapted to live within water flow conditions.
During water distribution of trans border water resources, only water is considered irrespective of water ecology. If we want to consider river ecology, especially for maintaining fish population, and want to estimate minimum water flow, what procedure may be adopted to identify minimum required flow?
Well,
brief answer; the flow that ensures dissolved oxygen concentration is greater than 3 mg / L.
Sincerely
There have been various instream flow methodologies developed. A lot depends on the natural range of variation and species present. Some use a minimum value of 7Q10 (the weekly average low that occurs at 10 year frequency). For channel maintenance, there should be at least a bankfull event every year or two to prevent vegetation encroachment, move sediment to maintain channel dimension. I would suggest that one size or cookbook approach is not going to fit all circumstances. Perennial side tributaries along rivers can be localized habitat refuges of cool water and elevated oxygen for mobile species as they enter warm and low oxygen rivers. Fishery and aquatic biologists are apt to have information on the needs of species present. There may be other water use needs to consider, such as swimming, scenic, water available for emergencies as fire control, community and industrial needs, waste treatment and water discharge standards, etc. Some ecosystems also provide important habitats for water birds and animal species.
In my opinion the minimum stream flow to consider river ecology should be slected to ensure sufficient reaerarion from ambient air and that it is the flow to ensure a minimum self cleansing velocity = 0.6 m/sec.
As per internet search, I came accross various a method called "Tennant methods". But I don't understand the various calculations. This why, I am in search of a method easy to understand.
Hi, perhaps it could be interesting:
Article Characterizing effects of hydropower plants on sub-daily flow regimes
Conference Paper Trade-off Between Environmental Flow Policy and Run-of-River...
Chapter Caudales ambientales a escala regional: una metodología basa...
Article Flow regime patterns and their controlling factors in the Eb...
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