The coastal inundation mapping informs Council processes and our statutory obligations, including LIM notations, processing of resource consents and consideration in building consents.
The Council is required by the Local Government Official Information and Meetings Act to include natural hazard information on a LIM if it is known to us.
Under the RMA 1991, councils are required to recognise and provide for the management of significant risks from natural hazards as a matter of national importance (s6(h)) and to have particular regard to the effects of climate change (s7(i)).
National instruments prepared under the RMA 1991 place requirements on councils. The New Zealand Coastal Policy Statement 2010 (NZCPS) details existing national objectives and policies for coastal natural hazards. Policy 24 requires councils to identify coastal areas that will be potentially affected by coastal hazards over at least 100 years. Policy 25 sets the policy framework for planning decisions for land use and development in areas potentially affected by coastal hazards, with an emphasis on avoidance and reduction of risks.
Councils must give effect to the NZCPS and other national direction through their regional policy statement, regional plans and district plans. The operative suites of resource management plans for the two districts set out the [current] management regimes for dealing with risks from natural hazards and include controls on the use of land for the purpose of the avoidance or mitigation of natural hazards (Inundation Practice Note: Calculating minimum ground and/or floor levels for subdivision, new buildings and major alterations’ NCC and TDC, 2019).
For Nelson City Council, there is a review of the planning documents currently underway. The broad approach to coastal inundation will be developed through that process, and involve engagement and consultation with the community as recommended via the Ministry for the Environment’s Coastal Hazard. This means that further information may be produced and information may change.
Both Nelson City Council and Tasman District Council already account for sea level rise and inundation when issuing resource consents. The approach taken for managing risks from inundation is explained in the ‘Inundation Practice Note: Calculating minimum ground and/or floor levels for subdivision, new buildings and major alterations’ (NCC and TDC, 2019).
When considering an application for resource consent, Council must have regard to any actual and potential effects on the environment of allowing the activity, including the effects arising from natural hazards (s104).
Council may refuse or grant a subdivision consent subject to conditions if there is a significant risk from natural hazards (s106). Any assessment of the risk from natural hazards requires a combined assessment of:
(a) the likelihood of natural hazards occurring (whether individually or in combination); and
(b) the material damage to land in respect of which the consent is sought, other land, or structures that would result from natural hazards; and
(c) any likely subsequent use of the land in respect of which the consent is sought that would accelerate, worsen, or result in material damage of the kind referred to in (b) above.
Conditions attached to subdivision consents granted may include the protection of the land and any adjacent land against natural hazards including inundation (s220).
For any new subdivision and development, an applicant will need to demonstrate that newly formed allotments contain adequate space for buildings which are not subject to material damage from inundation in response to a 1% AEP design event (refer to Section 2.3). Furthermore, it will need to be demonstrated that in achieving this there are no adverse effects (raised flood levels, diversion of flood flows and/or secondary flood routes) that occur on adjacent or surrounding property in response to this design flood event. Other resource management plan considerations such as amenity and servicing also need to be incorporated into design and decision making processes.
For other development (on existing titles) subject to the RMA 1991, the practice note process will be the same as for subdivision and development as described above. However, the full application of this process may be modified on a case by case basis where the development is of a limited duration and consequently will not be subject to long term projected climate change effects ((Inundation Practice Note, TDC and NCC, 2019, pg7-8).
As for the Resource Consent process above, both Nelson City Council and Tasman District Council already account for sea level rise and inundation when issuing building consents. In March 2019, both Council’s adopted the ‘Inundation Practice Note: Calculating minimum ground and/or floor levels for subdivision, new buildings and major alterations’. The Inundation Practice Note will continue to apply, and be subject to regular reviews.
The Inundation Practice note sets out a standard approach for industry professionals (e.g. surveyors and engineers) and Council to calculate acceptable floor and ground levels, given the Ministry for the Environment’s predicted increase to sea levels. The document also explains Councils approach under the Building Act 2004 in more detail.
The Building Act 2004 manages natural hazards in relation to the construction and modification of buildings. Council is required to take into account certain natural hazards, including inundation, when determining whether to grant building consents on land subject to specified natural hazards, with certain exceptions (under s.71-74). The emphasis in the management of natural hazards is to encourage people to avoid situations in which they or their property could be at risk:
E1 of the Building Code requires buildings and site work to be constructed to protect people and other property form the adverse effects of surface water. Performance E1.3.2 requires that surface water, resulting from and event having a 2% AEP [i.e. 1 in 50 year event], shall not enter housing, communal residential and communal non-residential buildings (Inundation Practice Note, TDC and NCC, 2019, p8).
The Inundation Practice
Note also sets out Council’s approach to Hazard Notices under the Building Act