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Flood Management | Changes in Selwyn

By Lisa Perry and Laurie Atkinson, Planners, Baseline Group | Sept 08, 2023

Natural hazards pose a growing threat to communities and properties worldwide, and New Zealand is no exception, meaning flood management is essential. A recent example is the Selwyn River flood that occurred in July of this year.To address such challenges amongst others, Selwyn District Council establishes a District Plan. At present Selwyn has two district plans: the outgoing Operative District Plan and the new Partially Operative District Plan (PODP) Within these plans is a significant focus on flood management. It's crucial to understand the implications of both plans when engaging in land development.

How have the new district plans shifted focus to natural disasters?

One of the significant shifts in the new plans is the focus on flood management. There is now greater emphasis on natural hazards. The old plan, which featured two maps related to natural hazards, the new plan encompasses a comprehensive set of 18 maps related to natural hazards.

What are the requirements for a Flood Assessment Certificate?

Under the new plan, there is now a requirement for Flood Assessment Certificates for various scenarios, including new dwellings, main buildings, new subdivisions, and additions of 25 m² or more to existing structures. These certificates, issued by the Selwyn District Council, determine whether your land or proposed activity is susceptible to flooding. Additionally, they provide specifications for the minimum finished floor level required to mitigate and manage flood risks.

This requirement primarily pertains to areas within the Plains Flood Management map of the new plan, which covers a substantial portion of the Selwyn District southeast of the foothills. If your property is not situated on higher ground, it is likely to be affected.

The specific requirement is to have a finished floor height at least 300 mm above the 200-year Annual Return Interval (ARI) flood event (a flood that has a 0.5 % chance of occurring in any given year). For new subdivisions, a Flood Assessment Certificate will be issued for each new lot created by the subdivision.

How do you get a Flood Assessment Certificate?

To obtain a Flood Assessment Certificate, the most significant requirement for developers and individuals will be providing site specific flood information and a site-specific flood hazard assessment prepared by a suitably qualified and experienced person to confirm flood management is in place. Dwellings or main buildings on rural sites will require a recent site-specific flood hazard assessment from Environment Canterbury. Subdivisions will require an assessment from a suitably qualified and experienced person confirming flood levels for each lot, and if the land is below the 200-year flood event level, details of minimum floor levels for each lot will need to be provided in order to confirm flood management has been established.

Why is implementing this flood management so important?

Although adjusting to new requirements can be tricky, avoiding a Flood Assessment Certificate is not an option and will only delay the resource consent process. As with any new requirement, there will be a period of adjustment to understand what acceptable information on flood management looks like. Over time, more and better information will become available, which will help developers, individuals, and Council officers alike. The intent of the changes is to protect people and property from the devastating effects of flooding. Given future flood predictions in relation to global climate change, protecting you and your property from natural hazards is crucial.

For more information on flood management and gaining your flood assessment certificate, contact us today!

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