Federation Villages Floodplain Risk Management Study and Plan
Discussion of Results
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Response Modification Measures and Property Modification Measures tend to score more highly than Flood Modification measures, as they can be implemented for a relatively low cost, lead to the reduction of property damage and improvement in community resilience in the long term, and do not incur negative environmental impacts; Majority of flood modification measures, that is, structural options, do not score well in terms of economic merits. Reasons for this include: o “Tangible Benefits” included in the Cost Benefit Analysis are determined from the reduction in property damages (Annual Average Damages (AAD), Section 5.5). o In the same vein, to reduce property damages, structural options need to effectively reduce flood risk in rare events. To do this, structural options need to be substantial in size, i.e. levee height or basin storage capacity – leading to high capital costs, land purchase requirements, and ongoing maintenance costs. The lowest scoring option Aquatic Centre Dam Outlet Upgrade (FMU-07), which involve replacement of the Aquatic Centre Dam Outlet involves substantial capital works for very little benefit in terms of flood risk reduction. Other lower scoring options are drainage focused options and therefore do not have significant benefits in larger flood event.
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The multi-criteria matrix assessment results, presented in Table 29, can be used to both understand the benefits and disadvantages of individual options, but to also see trends across the full suite of options assessed in the FRMS&P. The following results and trends are noted: • Managing Development in the Flood Prone Areas (PM-06/07) and Voluntary Purchase (PM-05) received the highest score, as they deliver benefits across a range of criteria including economics, reduction in flood risk, property affectation, as well as playing a small role in community flood awareness; • Flood Planning Level (PM-01), Flood Planning Area (PM-02), and Community Education and Awareness (RM-02) are the next highest scoring as they are effective methods to reduce property damages in the study area, and have additional benefits relating to improvements to community flood awareness.
118048: R211211_FederationVillagesFRMSP.docx: 11 December 2021
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