Floor Levels Above the 2% Flood Event - Are they High Enough?

Stormwater Conference

The 2% Annual Exceedance Probability (AEP) flood level is our national benchmark, defined by Clause E1.3.2 of the Building Act. This level of service is used widely across the country with few territorial authorities requiring a more conservative approach. When applied to the letter, this level of service can have some unintended consequences and risks the creation of future flood disasters.

A 2% AEP flood event can be close to impossible to define, particularly when multiple flooding sources need to be accounted for, which can include rainfall, tidal, tsunami, rivers, stopbank/dam failures and infrastructure blockages. The uncertainty associated with the derivation of design events from short term records and ‘best guess’ allowances for climate change should also be accounted for. We look at the approaches and solutions that have been applied in the Canterbury environment and how these have fared in recent significant flood events. We also present recent case studies from residential developments and proposed plan changes where a higher level of service than required by the building act was provided and how this will help to reduce the probability of future flood disasters.

Conference Papers Resource - Conference Papers Stormwater

2. Luke Edwards.pdf

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22 Jun 2016