Dr Roger Wade Environment Agency. Severn Tidal Impoundments Environmental Unknowns. The role of the Environment Agency. Regulator Operator Advisor. Hydraulics and Geomorphology. Erode or Deposit? The impact on Flood Defence. – May have some benefit but other impacts.
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Dr Roger WadeEnvironment Agency Severn Tidal Impoundments Environmental Unknowns
The role of the Environment Agency • Regulator • Operator • Advisor
Hydraulics and Geomorphology Erode or Deposit? The impact on Flood Defence. – May have some benefit but other impacts.
Climate change impacts drainage coastal development channel morphology UPSTREAM DOWNSTREAM defences natural habitats de-commissioning
Water Quality and Quantity Water Quality Algal activity –( eutrophication). Could be added cost Water Resources – future availability? May be improved.
Fish and habitats directive. • The estuary is an important nursery area for fish • Over 100 species are found • Some species are protected by the Habitats Directive • Over 25% of the salmon in England and Wales spawn in the rivers affected • Twaite Shad spawn in 4 rivers in the UK- 3 of which are upstream of the Cardiff Weston Barrage. • Compensation for any loss may not be possible. • We do know turbines kill fish.
Proposed turbine designa 7m diameter “Straflo” turbine 9 OR 10m proposed for Severn. AT 60 rpm BLADE TIP VELOCITY WOULD EXCEED 30 M/S
turbine mortality (source STPG, from SDC Report 2007). Salmon - adults = 40% - smolts = 10% Eels adult = 28% Shad juvenile = 53%
EUROPEAN EEL – Anguilla anguilla European Eels in decline and now protected by Eel Regulations. Valuable commercial net fishery for elvers Long lifetime (up to 30 years ) makes prediction of impact very difficult
The Environment • Messages from the Bay of Fundy-Eric Van Walsum • “Environmental Issues need to be part of the Design”
Conclusions • The last 30 years – knowledge gaps • Unknowns and risk • The Challenge! Can we find an option to produce energy and not respect the environment?