Lower Swansea Valley Flood Scheme Background Lower Swansea Valley - - PowerPoint PPT Presentation

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Jan 12, 2023 11 likes •201 views

Lower Swansea Valley Flood Scheme Background Lower Swansea Valley Regionally important economic area 18 th Century heavy industry 1980s enterprise park commercial and retail Investigate problem Update hydrology and improve 1D-2D

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Lower Swansea Valley Flood Scheme

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Background

Lower Swansea Valley Regionally important economic area 18th Century heavy industry 1980s enterprise park – commercial and retail

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Investigate problem

Update hydrology and improve 1D-2D hydrodynamic model. Found:

vertopping 1 in 10 annual

chance event 284 businesses and 16 homes 1 in 100 annual chance Flood hazard due to depths, velocity & transient population Northern embankment substandard factor of safety

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Remove redundant bridges New embankments & walls New flood walls Raised embankments Raise embankment New footbridge New embankment, set back from river NORTH SOUTH River Tawe Fendrod River Tawe New culvert debris screen and flood walls Remove watermain and existing bridge New embankments London railway + emergency planning and awareness raising Remove embankment New wetland habitat area

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Removing redundant structures

Remove redundant bridges River Tawe Footbridge above design flood level

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Making Space for Water

Proposed setback embankment Existing embankment removed River Tawe Caravan Park M4 N Lowered wetland habitat creation along historic river alignment

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Existing

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Summer 2013 - Earthworks

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Excavation of cut off trench

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Installation of new bridge

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Conclusions

Collaborative approach

NRW-CCSwansea Galliford-Black&Veatch