It is my understanding that the lagoons will be constructed along side the estuaries which will fill up with the incoming tide. The electricity will be generated by turbines when the water is released from the lagoons at the bottom of the tide. A big tide over on our coast is 5.7m but over on the West coast it's often double that number. Theoretically the migratory fish should not be effected by the lagoons as they will continue to run in the main water course, that said, it's not uncommon for Salmon and Sea Trout to make their way into Royal Quays marina when the Tyne is running above it's normal level.
I think there are several proposals on the table, the ones i have seen, detail a 'Unidirectional rotor', which will be driven as the tide is in both ebb, and flood.
The only 'None flow' period will be at the top of the tide cycle. The 'lagoon'ebb period will be greatly extended, as they will control the outward flow to maximise the peak generating period of the turbine. this will be dictated by: the size,(Capacity/Volume.), of the lagoon, The Number/Size/ Efficiency of the turbines employed. You could well be looking at minimal,( Or Negative?), dwell period at the bottom of the tide cycle.
This will impact the enviroment greatly, in many ways. Some will be beneficial, some will not. There will be species that prosper in the 'Lagoons', and those that will not.
The thing is that the impact must be understood. It must be done with care, and controlled, and the voice of 'All Angling' must be heard, play its role as early as possible!
It would make sense to utilise the 'lagoons' for some sort of fish farming ?
If this were Oyster/ Mussel, etc. it would not be of major concern, as they already exist in several estuary systems without problems, but what if this was fish farming, (Salmon, Bass, etc.) ? The major damage created by such operations, on the Aquatic enviroment is well documented, and very concerning.
In principal I am very much in favour of the lagoon proposals,(Anything to break the dependence on Oil,& Gas, that doesn't make you glow in the dark

), but the people creating these will be working to margins/returns...that concerns me ?
Unless Angling gets in now...it will be ignored. sidelined ?
M....