Stage 5 Superlot Subdivision) These conditions apply to
F: STORMWATER DISCHARGE PERMIT (S15)
servicing less than 10 delineated uncovered carparks Mixed Risk
JOAL /
Private road servicing 10 and up to 29 delineated uncovered carparks High Risk
JOAL /
Private road servicing 30 or more delineated uncovered carparks
increase maximum flood water levels upstream of the Sutton Road Culvert 2 under the North Island Main Trunk railway for events up to and including the 100- year ARI rainfall event.
external walls, and to have rainwater harvesting tanks JOALs / Private Roads
• Preference for discharges to be directed to large (communal)
bioretention devices to have gross pollutant pre-treatment as a minimum provided through catchpits.
Alternatively, at-source options as follows:
Low Risk
• Catchpits with grate, sump volume and submerged at outlet at a minimum or any other devices as outlined in Mixed or High Risk
Mixed Risk
• Bioretention device (rain garden, tree pit);
• Swale High Risk
• Bioretention device (rain garden, tree pit);
• Swale;
• Or GD01 equivalent device
• Private trafficked impervious surfaces to use catchpits with a grate, sump volume and submerged outlet at a minimum, or bioretention devices such as raingardens and tree pits, which will be supplemented with tanks for the detention
(where this is not achieved in a bioretention device Road
corridors
Treatment to GD01 for all roads and carparks
Bioretention devices including pre-cast devices and larger, aggregated devices which are preferred
Large communal
bioretention devices to have gross pollutant pre- treatment as a minimum through catchpits
Reserves None Southern sub-catchment
the drainage reserves will include two attenuation basins (for flood attenuation and hydrological mitigation) 187a. Stormwater Implementation Management Plan (SIMP) for 76 and 76A Waihoehoe Road The consent holder must prepare and submit for 76 and 76A Waihoehoe Road a Stormwater Implementation Management Plan to Auckland Council Team Leader – Compliance and Monitoring for certification and prior to submission for Engineering Plan Approval (EPA). The SIMP must:
(a) address how the Stormwater Management Works achieve the design requirements in Condition 187;
(b) describe all the proposed public devices for stormwater attenuation, quality and hydrological SMAF-1 mitigation. This must include a description of the type of device, dimensions (including detention volume),number and location of devices, and the proposed function of the device including hydrological mitigation and/or water quality mitigation;
(c) define the risk criteria performance standard for water quality for future trafficked areas within superlots and residential lots.
187b. The Stormwater Management System for 76 and 76A Waihoehoe Road must be implemented in accordance with the certified SIMP under condition 187A above.
188. The following stormwater management measures are required
a. Stormwater treatment to include vegetation coverage of rain garden surfaces and fringes of wetlands, attenuation basins and streams and partial shading so that to provide sufficient shading to avoid increaseds in surface water temperatures are avoided.
b. All stormwater outfalls must incorporate energy dissipation and / or erosion protection measures which will minimise bed scour and bank erosion.
c. For the southern sub-catchment, the use of Attenuation Basin 1 and Attenuation Basin 2 or similar devices to not increase maximum water level or peak discharge from pre-
Commented [BA17]: Addition of conditions 187 and 187b requiring SIMP is provided for 76 Waihoeohe Road site – in response to Technical Stormwater and Flooding Report dated 9/6/2022
Commented [BA18]: Amended to better clarify purpose of condition to avoid increased surface water temperatures – in response to Technical Stormwater and Flooding Report dated 9/6/2022
development to post-development at the Sutton Road Culvert 2 for events up to the 1 in 100-year ARI rainfall.
d. Maintenance of similar surface water catchments into the wetlands, ensuring the hydraulic neutrality of wetlands between pre and post development.
e. Design (i.e., detailed design) is completed in accordance with Auckland Council Code of Practise Version 3 including climate change provisions.
Modifications approval
189. In the event that any modifications to the stormwater management system are required, that will not result in an application under section 127 of the RMA, the following information must be provided:
(a) Plans and drawings outlining the details of the modifications; and
(b) Supporting information that details how the proposal does not affect the capacity or performance of the stormwater management system.
All information must be submitted to, and approved by the Council, prior to implementation.
Advice Note:
All proposed changes must be discussed with the Council, prior to implementation. Any changes to the proposal which will affect the capacity or performance of the stormwater management system will require an application to the council under section 127 of the RMA.
Pre-construction meeting
190. A pre-construction meeting must be held by the consent holder, prior to commencement of the construction of any stormwater devices onsite, that:
(a) is arranged five working days prior to initiation of the construction of any stormwater devices on the site;
(b) is located on the subject area;
(c) includes the relevant Auckland Council representative(s); and
(d) includes representation from the site stormwater engineer (or contractors) who will undertake the works and any other relevant parties.
Advice Note:
To arrange the pre-construction meeting required by this consent, please contact the Council on email at monitoring@aucklandcouncil.govt.nz.
191. The following information must be made available prior to, or at the pre-construction meeting:
(a) timeframes for key stages of the works authorised under this consent;
(b) erosion and sediment control measures during construction activities;
(c) contact details of the site contractor and site stormwater engineer; and
(d) construction plans approved (signed/stamped) by the council’s Development Engineer.
192. A post-construction meeting must be held by the consent holder, within 20 working days of completion of the stormwater management works, that:
• is located on the subject area;
• includes relevant Auckland Council representative(s); and
• includes representation from the site stormwater engineer (or contractors) who have undertaken the works and any other relevant parties.
Certification of stormwater management works (as-builts)
193. As-Built certification and plans of the stormwater management works, which are certified (signed) by a Chartered Professional Engineer as a true record of the stormwater management system, must be provided to the Council for approval.
194. As-Built Plans must be provided to the Council twenty (20) days prior to the post-construction meeting required by this consent.
195. The As-Built plans must display the entirety of the stormwater management system, and must include:
(a) the surveyed location (to the nearest 0.1m) and level (to the nearest 0.01m) of the discharge structure with co-ordinates expressed in terms of NZTM and LINZ datum;
(b) location, dimensions and levels of any overland flowpaths including cross sections and long sections;
(c) plans and cross sections of all stormwater management devices, including confirmation of the Water Quality Volume, storage volumes and levels of any outflow control structure;
(d) the surveyed locations of all soak holes installed for the management of stormwater discharges to ground must be measured to the nearest 0.1 metre with co-ordinates expressed in terms of NZTM;
(e) the soakage capacities of the soak holes; and
(f) documentation of any discrepancies between the design plans and the As-Built plans approved by the Modifications Approval condition.
Operation and maintenance plan
196. An Operation and Maintenance Plan must be submitted to the Council for approval.
197. An Operation and Maintenance Plan must be provided to the Council five (5) days prior to the post-construction meeting required by this consent.
The Operation and Maintenance Plan must set out how the stormwater management system (public and private) is to be operated and maintained to ensure that adverse environmental effects are minimised. The plan must include:
(a) details of who will hold responsibility for long-term maintenance of the stormwater management system and the legally effective organisational structure which will support this process;
(aa) details of how any failures will be addressed or remedied;
Commented [BA19]: Minor amendments to condition in response to Technical Stormwater and Flooding Report dated 9/6/2022
(b) a programme for regular maintenance and inspection of the stormwater management system;
(c) a programme for the collection and disposal of debris and sediment collected by the stormwater management devices or practices;
(d) a programme for post storm inspection and maintenance;
(e) a programme for inspection and maintenance of the outfall;
(f) general inspection checklists for all aspects of the stormwater management system, including visual checks; and
(g) a programme for inspection and maintenance of vegetation associated with the stormwater management devices.
198. The stormwater management system must be managed in accordance with the approved Operation and Maintenance Plan.
199. Any amendments or alterations to the Operation and Maintenance Plan must be submitted to, and approved by the Council, in writing prior to implementation.
200. The Operation and Maintenance Plan must be updated and submitted to the Council for approval, upon request.
Operation and maintenance
201. The stormwater management system must be maintained to ensure all onsite waterways are clear from obstructions, erosion or hazards to safety.
202. Roading, kerbs and channels constructed across overland flow paths must be set at a level that maximises the capture of water by road cesspits. Other than at designated overland flow paths, driveway crossings must be constructed in order to minimise the overflow of water from the road into private properties.
203. For stormwater flows in excess of the capacity of the primary drainage systems, overland flow paths must be provided and maintained to allow surplus stormwater from critical storms (up to the 100 year ARI event), to discharge with the minimum of nuisance and damage. Overland flow paths must be kept free of all obstructions.
204. Secondary flow paths must be kept free from obstructions such as buildings and solid fences.
205. Details of all inspections and maintenance for the stormwater management system, for the preceding three years, must be retained.
A maintenance report must be provided to the Council on request.
206. The maintenance report must include the following information:
(a) details of who is responsible for maintenance of the stormwater management system and the organisational structure supporting this process;
(b) details of any maintenance undertaken; and (c) details of any inspections completed.