1-in-100 years standard is a gamble, or time to go Dutch on flood planning

Abstract

Referring to the recent Queensland and Victoria floods, this article looks at Australian flood safety standards from the perspective of a flood-sensitive country on the other side of the globe, the Netherlands. From this perspective, the widely accepted ‘1-in-100 year flood’ standard is considered to be surprisingly low. In comparison, the Netherlands’ flood prevention system is based on a variable 1-in-1250 to 1-in-10,000 years standard. A major argument for this high and costly standard is that it convinces foreign investors that their investments will be safe, insurable and re-insurable on a long-term basis. Spending billions on flood prevention is an indispensable way of keeping the flood-sensitive country trustworthy and creditworthy. Similar arguments apply to Australia. Taking into account the obvious differences in geography, size and density, it could sensibly be argued that Australia should raise its standards for urban and industrial areas to the 1-in-1000 to 1-in-2000 range. This will be a costly affair, but arguably no more costly than the current practice of waiting for the flood to come and paying billions of dollars afterwards.

Keywords:

• flood planning
• flood safety standards
• the Netherlands