Most papers discussing MBV (Miljöbasert vannföring – environmental water flow) suggest different methods to assess minimum water flow in a regulated river but conclude in adaptive conditions and management. In contrast NVE has decided year 2012 that the revision of conditions for Folla-Vindölareguleringen in Surna is governed by Vassdragsreguleringsloven and thereby new conditions are valid for 30 years. To add to the confusion the Norwegian Parliament voted for Vannderiktivet year 2008 and there conditions for a regulation shall be assessed every 6 year. The main variable is time and we believe a river is defined by the work its dynamic flow is performing. Biological productivity and diversity are produced in habitats that are created in another flow from a previous time. Boundaries and habitats of a river transform and move all the time and to assess them statically and in a decoupled manner can result in unsound conditions.
The main description of a river is off cause the Navier-Stoke equation (you can Google it), a natural rivers energy consumption is driven by gravity and viscosity. However, pure Navier-Stoke equations can be heavy for a computer but energy consumers as the KE turbulence model can be used in a smeared approach. A natural river is an energy eater in performing biological work, and biological energy of the natural river must be a start in the assessment of regulations to balance the impact of potential energy taken over time and transformed to electricity. As of now tourist industries dependent on rivers diversity and the power industry do not speak the same language. In Norway a rivers environment is handled by OED (where NVE is preparing the material), the Norwegian Ministry of Petroleum and Energy.