The recent Land and Environment Court decision in Gardiner v Central Coast Council [2022] NSWLEC 1007 provides a timely reminder of the Planning Principles that must be considered when determining whether a flood strategy lodged with a subdivision application on flood prone land is adequate.

Applying the ‘Plan of Management’ Planning Principles (Renaldo Plus 3 Pty Limited v Hurstville City Council [2005] NSWLEC 315), the Court held that the residential subdivision could not rely on a 'stay in place' flood strategy which did not provide sufficient level of certainty that the measures could be implemented when a flood event occurs.

Key points

The case was an appeal against Central Coast Council’s deemed refusal of a two lot residential subdivision of land near the Wyong River.

The Applicant proposed a 'stay in place' flood strategy for the development, relying on education, early evacuation, and ‘shelter in place’ protocols for residents until flood waters recede.

The Applicant proposed alternative services including solar power, battery backup, onsite sewer, rainwater storage and medical supplies to support the 12 hour isolation period of residents during inundation. It was proposed positive covenants and maintenance schedules could be implemented to ensure all emergency systems would be operational in a flood event.

The site is in an existing low density residential area and is a Flood Control Lot, with the entire site inundated in a 1% flood and PMF.

Council’s planning documents do contemplate a shelter in place strategy in certain circumstances (such as certain flash flooding areas), which did not apply in this case. Council contended the demand on emergency services would place unreasonable social and economic impost on the community with potential to increase risk to life and property.

Planning Principles applied

When considering the adequacy of the flood strategy, the Court considered the Planning Principles that apply to assessing the adequacy or appropriateness of a plan of management (see Renaldo Plus 3 Pty Limited v Hurstville City Council [2005] NSWLEC 315):

1. Do the requirements of the strategy require people to act in a manner that would be unlikely or unreasonable in the circumstances of the case?

2. Can the people the subject of the strategy be reasonably expected to know of its requirements?

3. Do the requirements in the strategy require absolute compliance to achieve an acceptable outcome?

4. Is the strategy enforced as a condition of consent?

Acting Commissioner Morris found the flood strategy did not provide sufficient level of certainty that the measures could be implemented when a flood event occured; and the strategy relied on too many systems and processes being in place to minimise risk, with no guarantee the occupants would be aware of the complex and costly requirements.

In addition the conditions of consent could not ensure the necessary resident education, continued maintenance or compliance with ‘shelter in place’ would occur. The Court confirmed Council should not have to ensure ongoing compliance with a strategy that safeguards the occupants of the land, the strategy should be self enforcing.

The appeal was dismissed and the subdivision refused.

Implications for councils and applicants

Applicants: if an application relies on a plan of management or strategy to be implemented by occupants, ensure it meets the tests in the Planning Principles set out in Renaldo.

Councils: when determining residential development on flood prone land, assess any proposed flood safety measures against the Renaldo Planning Principles and ensure they are not overly complex and do not rely on unreasonable expectations of residents to ensure their safety.