Barnstaple Flood Defence Improvements Phil Emonson, Principal Analyst 20th April 2016 Contents 2014-15 study Flood cells and existing defences Fluvial risk and tidal risk Discounted options Option 1 and 2 Effectiveness Costs 2015-16 study Works completed to date
Barnstaple Flood Defence Improvements | JBA Consulting FLOOD DEFENCE OPTIONS APPRAISAL 2014-15 Flood Cells Barnstaple Flood Defence Improvements | JBA Consulting Existing Defences Revetments along River Taw Embankment in Pilton Park Barnstaple Flood Defence Improvements | JBA Consulting Tarka Trail and flood wall Floodplain storage Pilton Park
Flood walls along River Yeo Sheet piling Fluvial Flood Risk 2015: Most risk is in Cells A and E 2075: Big increase of risk in Cell B, and to a lesser extent A and E 2115: Significant increase of risk in Cell B, and C 2015 2075 2115 Total properties
176 518 1,269 Economic damages 11.8M 53.2M 166.3M Barnstaple Flood Defence Improvements | JBA Consulting Tidal Flood Risk 2015: Most risk is in Cell B 2075: Big increase
of risk in Cell B, and to a lesser extent A, C and E 2115: Significant increase of risk in Cell B, C and E 2015 2075 2115 Total properties 142 968 2,172 Economic damages
1.3M 80.2M 257.5M Barnstaple Flood Defence Improvements | JBA Consulting Discounted Options Option Why Discounted? Do nothing Deterioration of defences Potential loss of life Huge damage to property and infrastructure
Do minimum (maintain existing) Demountable defences Barnstaple Flood Defence Improvements | JBA Consulting Increased frequency of flooding Increased damage to property and infrastructure Need for a permanent solution strategic planning purposes Deployment challenges Discounted Options Option
Why Discounted? Tidal barrier Estuary is a SSSI Only really benefit Cell A V high costs, and only provides protection from tidal sources Source control (SUDS) Not strategic On a case by case basis with each development DCC now Statutory Consultee Estuary is a SSSI Not a permanent solution Increase channel
capacity Barnstaple Flood Defence Improvements | JBA Consulting Flood Defence Options Barnstaple Flood Defence Improvements | JBA Consulting Option 1 Flood Options Cell A Raising A361 and cycle track north towards Pilton Community College Embankment / land raising around edge of Bradiford Nature Reserve Property level protection (PLP) for properties in Meadow Road area Replace the existing tidal defences over time to meet required standards B
Raising of A361 and cycle track north towards Pilton Community College Raised wall along Rolle Quay Increased parapet along Rolle Street Bridge Piling around existing course of Yeo through Pilton Park Replace /upgrade existing tidal defences over time to meet required standards Barnstaple Flood Defence Improvements | JBA Consulting Option 1 Flood Cell Options C
D Replace / upgrade existing tidal defences over time to meet required standards E Replace the existing tidal defences over time to meet required standards Flood walls along Coney Gut F Flood defences are being upgraded imminently as part of the Anchorwood Bank development Raise wall opposite Raleigh Road Flood relief culverts beneath A39 bridge
Wall raising along Castle Quay Raised existing tidal defence Barnstaple Flood Defence Improvements | JBA Consulting Option 2 Barnstaple Flood Defence Improvements | JBA Consulting Effectiveness Fluvial (1% AEP) Tidal (0.5% AEP) 2015 baseline 176 142 2075 do minimum
518 968 2075 Option 1 45 7 2075 Option 2 45 7 1269 2172
2115 Option 1 46 7 2115 Option 2 46 30 2115 do minimum Barnstaple Flood Defence Improvements | JBA Consulting Cost Option 1 Option 2
Low cost (k) High cost (k) Low cost (k) High cost (k) Cell A 4,815 8,968 4,815 8,968 Cell B 9,767
36,284 3,045 11,182 Cell C 2,129 4,099 2,479 6,035 Cell D 1,152
2,139 1,152 2,139 Cell E 8,484 15,656 8,484 15,656 Cell F TOTAL Excluded from analysis 26,348
67,146 19,975 Capital costs including prelims and optimism Barnstaple Flood Defence Improvements | JBA Consulting 43,979 BARNSTAPLE FLOOD DEFENCES PHASE 2 2015-16 Outline of works Works completed Service searches, topographic survey and Ground Investigation scoping Design concepts (for defences along Rolle Quay as well as Pilton Park)
Preliminary sizings, calculations and drawings Preliminary Environmental Assessment (PEA) Landscape and Visual Impact assessment Works planned Outline Water Framework Directive assessment Supporting NDDC in outline plans for Pilton Park Completion of concept drawings and visualisation Stakeholder engagement Reporting and identification of needs for further survey / assessment Barnstaple Flood Defence Improvements | JBA Consulting Possible alignments Barnstaple Flood Defence Improvements | JBA Consulting Possible alignments
Barnstaple Flood Defence Improvements | JBA Consulting Thank you Phil Emonson Principal Analyst, JBA Consulting [email protected] Barnstaple Flood Defence Improvements | JBA Consulting
