Appendix 1
Perth and Kinross Council · 16 November 2022
Back to Climate Change and Sustainability Committee — 16 November 2022 and its agenda
Text extracted from the council's PDF. Layout and reading order may differ from the original.
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Appendix 1 Table 1: Option Appraisal Summary Table Option 1 Maintenance plus small flood defence ancillary works (The Cross and Abercairney Place) Option 2 Property Level Protection (PLP) (residential properties only) Option 3 Direct Flood Defences (Tullibardine & Highland Spring) + Property Level Protection (PLP) (residential properties) Option 4 Diversion Channel (Danny Burn / Back Burn / Kinpauch Burn) plus Direct Defences (Highland Spring) plus Natural Flood Management All properties protected (200 year event)? No No Yes Yes Initial Capital cost £841,769 £192,000 £4,635,345 £7,823,860 Benefit:Cost Ratio 1.4 2.9 1.77 1.36 Assessment of option Option doesn’t fully meet study objectives. Only defends The Cross and Abercairney Place. Other properties still at risk. Repeated dredging not recommended on environmental grounds. Option doesn’t fully meet study objectives. PLP not suitable for non-residential properties, which therefore remain at risk. Flood protection relies on measures being installed properly by homeowners (in advance of flooding), and suitable maintenance. Typical life span of around 20-30 years before replacement required. Uptake of PLP measures is historically poor. Only effective up to certain flood depths (typically 0.6m) – modelled 1 in 200 year flood depths are up to 0.4m (for residential properties). All properties offered a degree of protection but see below. Flood protection provided by PLP relies on measures being installed properly by homeowners (in advance of flooding), and suitable maintenance. Typical life span of PLP around 20-30 years before replacement required also. Uptake of PLP measures is historically poor. PLP only effective up to certain flood depths (typically 0.6m). – modelled 1 in 200 year flood depths are up to 0.4m (for residential properties). All properties defended – plus benefit to the A9. Diversion works are remote from the village thereby reducing impact (both during construction and longer-term). Visual impact of direct defences also limited. NFM opportunities through reuse of material claimed on site during construction. Potential for multiple benefits (biodiversity/habitat creation/amenity) along diversion routes and NFM. Option 1 is not recommended Option 2 is not recommended Option 3 is not recommended Option 4 is recommended