Lincoln University
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Flood mitigation capability assessment and classification

posted on 2022-12-18, 23:15 authored by Suphicha Muangsri, Wendy McWilliamWendy McWilliam, Tim Davies, Gillian LawsonGillian Lawson

The maximum flood mitigation capability (FMC) of each zone is evaluated by comparing the zone’s collectable runoff volumes with the amounts of catchment runoff reduction required to maintain flood protection objectives under climate change (FMC = 100∀C /CR). The required catchment runoff volume reductions (CR) are calculated by subtracting the amount of current flood protection capacity from the future catchment runoff volumes corresponding to each scenario and future period without GSI implementation. The collectable runoff volume (∀C ) is equal to the total amount of runoff from a zone drainage area if its potential in-ground storage capacity is not reached. However, if the total runoff volume from a drainage area exceeds the storage capacity, the surplus is assumed to discharge into the primary drainage system.

The results of FMC assessment are used to identify FMC classes grouping industrial SWM zones capable of mitigating the similar severity of climate change impact to below the current flood protection capacity. 

FMC sub-classes categorise SWM zones within each class by the key factor that limits their FMC. Sub-classes include the size of the drainage area (d), the high groundwater level (w), and the amount of potential GSI area (a).