NELSON CITY COUNCIL. Application for Resource Consent Remediation of Slip Damage to Cable Bay Road Cable Bay, Nelson

Transcription

1 NELSON CITY COUNCIL Application for Resource Consent Remediation of Slip Damage to Cable Bay Road Cable Bay, Nelson An Application to Nelson City Council Pursuant to Section 88 of the Resource Management Act 1991 Prepared by Planscapes (NZ) Ltd November 2012

2 APPLICATION FOR RESOURCE CONSENT To Nelson City Council Pursuant to Section 88 of the Resource Management Act 1991 To: The Chief Executive Officer Nelson City Council PO Box 645 NELSON 1. Applicant: Nelson City Council (Attn: Simon Talbot). 2. Proposal: To undertake earthworks and install retaining structures and replacement or upgraded culverts to remediate slip damage and reinstate the carriageway to Cable Bay Road following the December 2011 flood event. (A detailed description of the proposal is contained within Annexure A Assessment of Effects on the Environment and accompanying plans and diagrams in Annexure B and C). 3. Location: The application relates to Cable Bay Road, between within 574 and 780 Cable Bay Road. The location of the slip damage and proposed remedial works is shown on the site plan in Annexure B. 4. Legal Description: The activities subject of this application are to be contained within road reserve, except: Pt Sec1 Blk II Wakapuaka SD (CT31149) DA and CR Haig Lot 6 DP5832 (CT NL154/27) CJ Lewis and SE Lewis Lot 28 DP5832 (CT NL2B/977) MP and PA Dawson CTNL12B/1099 and Pt Wakapuaka Block 2 and Lot 4 DP (CT ) Cable Bay Farms Lots 1 and 2 DP (CsT and ) Cable Bay Farms. Copies any titles (beyond road reserve) are contained in Annexure F. 5. Owner / Occupier: Any land within road reserve is owned and administered by the Nelson City Council. Ownership of these other titles is noted above. CT31149, CTNL154/27 and CT NL2B/977 are residential properties. CsT and are undeveloped residential lots, each with a nominated house site well removed from the proposed earthworks in Site 21. The balance of land uphill of the road is owned and farmed by Cable Bay Farms. 6. Resource Consents: Resource consent under the land use and freshwater rules is sought for these activities. No further resource consents or permits are required under the Nelson Resource Management Plan. 1

3 7. Effects on the Environment: An assessment of actual or potential effects on the environment of the proposal is contained as Annexure A, prepared in accordance with Section 88 of and the Fourth Schedule to the Resource Management Act Other Information: The following information is enclosed to assist in understanding the proposal, and in accordance with the requirements of the Nelson Resource Management Plan: - Site plan (Annexure B); - Engineering Plans for Remediation Works Tonkin and Taylor Ltd (Annexure C); - Geotechnical Assessment Tonkin and Taylor Ltd (Annexure D); - Environmental Management Plan Tonkin and Taylor Ltd (Annexure E); - Certificates of title (Annexure F); - Consultation and Written Approvals of Affected Persons (Annexure G); - Photographs of the application site and existing damage, incorporated in the AEE. 9. Application Fee: This is to be addressed interdepartmentally within Council - please contact Simon Talbot for payment of the application fee.... (Signed by the Applicant or its Authorised Agent) Dated this th day of November 2012 Address for Service: Nelson City Council C/- Planscapes (NZ) Ltd PO Box 99 NELSON Attn: Jane Hilson Ph: (03) jane@planscapes.co.nz 0457application.doc 2

4 ANNEXURE A Assessment of Effects on the Environment Prepared by Planscapes NZ Ltd 3

5 INTRODUCTION 1. Nelson City Council seeks resource consent to undertake earthworks and install retaining structures and replacement or upgraded culverts to remediate slip damage within road reserve and reinstate the carriageway to Cable Bay Road following the December 2011 flood event. 2. The general location of the proposed works is shown in Figure 1 below: Figure 1: Application Site 3. Tonkin and Taylor Ltd has been engaged by Nelson City Council to investigate the options for remediation works at 28 identified sites along the road, and has provided a detailed engineering design for each of these (see Annexures B and C). 4. Tonkin and Taylor s brief was that all remediation works are to be contained within road reserve, and Cable Bay Road is to remain open to traffic at all times, as far as practical. The remediation works are to allow for construction of a 5.5m wide sealed carriageway (5.8m on bends), with 0.5m wide unsealed shoulder on the outer edge of the road. 5. The remediation works subject of this resource consent application include re-design and replacement of damaged culverts under the road, upgrading of culvert intake/outlet features, repair and/or installation of new retaining structures (gabion, concrete pole, timber or palisade walls) at slip sites, and fill placement where slumping of the road has occurred. Use of geogrid reinforced fill, with appropriate subsurface drainage, is proposed throughout. Relocation of several at-risk power poles has already occurred. 6. A basic description of the proposed remediation works is contained on Tonkin and Taylor s Drawings to in Annexure B. 7. Tonkin and Taylor Ltd has prepared an Environmental Management Plan for the project (Annexure E). This specifies the methodology that will be adopted during construction to manage stormwater runoff, sedimentation, dust and erosion arising from the earthworks, and to minimise disturbance to Cable Bay residents both in the hours of construction and road access to their properties. 4

6 8. Subject to the necessary resource consents being obtained, it is intended that construction is commenced over the summer period 2012/2013. The estimated duration to complete remediation of all 28 sites is 2-3 years. 9. Cable Bay Road is zoned Rural in the Nelson Resource Management Plan (NRMP). Resource consent is required under the earthworks and rural building rules and, for works in the bed of any stream (at 6 sites), the freshwater rules. The proposed earthworks and retaining walls are discretionary activities, and works to and around culverts within waterbodies a controlled activity, under the NRMP. 10. Adjoining properties down-slope of the proposed remediation works are: Adjoining Property Address Remediation Site Remediation Works Cable Bay Scenic Reserve 1A and 1B, 2A New timber retaining wall and extension to existing gabion wall, culvert inlet upgrade 574 Cable Bay Road 2B and 2C Culvert inlet upgrades and culvert extension 580 Cable Bay Road 2C, 3-11 Culvert inlet and outfall upgrades, culvert extension, upsize of existing culvert, nine new retaining walls (timber, gabion basket, concrete pole and panel, and palisade) 636 Cable Bay Road 12 and 13 New timber retaining walls 638 Cable Bay Road 14 and 15 Upsize existing culvert and upgrade its inlet and outfall, new gabion wall 660 Cable Bay Road Culvert inlet upgrade, three new retaining walls (gabion, timber and palisade)) 676 Cable Bay Road 19 and 20 New timber retaining wall, upsize existing culvert and upgrade its inlet and outfall 682 Cable Bay Road 21 and 22 Culvert inlet and outfall upgrades, new gabion retaining wall 698 Cable Bay Road 22 and 23 New gabion retaining wall, new timber pole and palisade retaining wall 718 Cable Bay Road 24 Timber retaining wall 744 Cable Bay Road 25 Culvert inlet upgrade 748 Cable Bay Road 25 Upsize existing culvert and upgrade its inlet and roadside watertable channel 778 Cable Bay Road 26 New gabion basket and palisade wall 780 Cable Bay Road 27 Culvert inlet and outfall upgrade, and improved roadside watertable channel, timber retaining wall 796 Cable Bay Road 28 Culvert inlet and outfall upgrade, and improved roadside watertable channel 11. The plans in Annexure C for each site include a Working Area and Erosion Sediment Control Plan. All work sites are fully contained within road reserve except for Sites 6 and 7 (extending up-slope), Site 14 (down-slope), and Sites 20, 21 and 27 (upslope) and Sites 27 and 28 (down-slope). In the case of Site 7 the anchors to the retaining wall, and the inlet riprap for the existing culverts at Sites 20 and 21, extend under or onto the up-hill property, and the outlet structures for culverts at Sites 14 and 28 extend onto the down-slope properties. Copies of these titles and identified of their owners are contained in Annexure F. 12. The Council, as Applicant, has consulted with the Cable Bay community by letter drop ( X May 2012), public meeting (X June 2012) and one-on-one meetings with those landowners identified in 10 and 11 above. 13. Written approvals from those adjoining land owners (and Iwi) considered to be potentially affected by the proposed remediation works are being sought where possible, copies of which will be submitted to Council with the application (Annexure G). 5

7 14. In the event that some, but not all, of the affected parties give written approval to this proposal, it is intended that this application be submitted in two parts: The first to deal with those sites and works consented by affected parties, to enable some priority to be given to that remediation; and A second application capturing the remainder of the sites, for which a notified application would be required. 15. The application is accompanied by a Geotechnical Assessment prepared by Tonkin and Taylor Ltd, and design plans for each of the slip or culvert sites requiring resource consent. This, and their Environmental Management Plan, form part of the Assessment of Effects on the Environment (AEE) accompanying this application. 16. The following assessment of the actual or potential effects on the environment of the proposed activities has been prepared in accordance with Section 88 of and the Fourth Schedule to the Resource Management Act FLOOD EVENT AND RESULTING DAMAGE TO CABLE BAY ROAD 17. Cable Bay Road is the only road access into the small rural community of Cable Bay. 18. As a result of the December 2011 Floods, the road was closed for several days by a large number of slips orientating from land both above and below the road. The extent of damage to the road and surrounding land is shown in Figure 2 and Photos A1-A4 below, and is described in the Tonkin and Taylor Geotechnical Assessment in Annexure D as generally earth flow ie a fluidised material mostly containing fine grained materials, topsoil, clay and colluviums together with slope vegetation and boulders of variably weathered rock which inundated the road. The road is now open to all traffic, but signage and traffic restrictions are to remain in place until the repair work is completed. 19. Tonkin and Taylor state in their Geotechnical Assessment: In the 10 months following the December rainstorm event there has been some localised slope failures following rainstorm events but nothing on the scale of the December 2011 event. The majority of the sites have remained in a similar condition to how they were following the general clean up after the December event. We assess the slopes to be marginally stable under normal rainfall events but are likely to experience localised reactivation of instability during high intensity rainfall events, although of lower intensity than the December 2011 event. 20. The Nelson City Council, as roading authority responsible for Cable Bay Road, has resolved to rebuild the road to the same level as it was before the floods. The full cost of these repairs is estimated to be $3.5million, and is subject to approval under the Long Term Plan and with NZTA funding its share of the costs of emergency works. PROPOSED REMEDIATION WORKS 21. There are 28 sites subject of the proposed remedial works (see Annexure B). 22. The engineering brief for the remediation design is outlined in 5.1 of Tonkin and Taylor s Geotechnical Report in (Annexure D). The design has been guided by geotechnical subsurface investigations and locating the start of the South Island fibre optic cable which is location within road reserve. 6

8 Figure 2: Cable Bay Flood Damage Photos A1-A4: Cable Bay Road Slip Damage 7

9 23. The geotechnical and civil work designed by Tonkin and Taylor are (Annexure D, pg 1): 1. Design of remedial works at 22 sites, including retaining walls up to 4m in height and between 12m and 80m long on the downslope edge of Cable Bay Road. 2. Design improvements to the road culverts and road stormwater drainage including: enlarging the inlet structures and improving the water table drains at 12 sites; replacing the culvert pipes with larger diameter pipes at 5 sites; protection of the culvert exit areas at approximately 6 sites; upgrading of the water table drains along sections of the road. 3. Earthworks design, including: temporary excavations to allow construction of the retaining walls and stormwater drainage works; permanent cuts upslope of selected culverts to increase sediment capture capacity; fill to be placed behind the retaining walls and culverts. 24. The proposed retaining walls along the road are either gravity walls or cantilever pole walls., with ground anchors added to the higher walls: a. cantilever walls, of increasing height: i. in-ground timber palisades, ii. timber pole walls (1m-2m high), iii. timber pole with ground anchors (2m-4m), iv. concrete pile with ground anchors (4m-8m). b. gravity walls, of increasing height: i. gabion (1m-2m), ii. anchored gabion (2m-4m). 25. Stormwater improvements have been designed to reduce the impact of another major storm event at Cable Bay Road by improving intakes to existing culverts and increasing the capacity of other culverts to accommodate a Q15 event where practicable, and with enhanced and dedicated secondary flow paths (concrete crossings within the carriageway) at selected higher flow sites (Sites 1, 5, 14, 20, 25 and 28) to cater for Q50 flows directed to existing culverts The remediation works for each of the 28 sites, shown in detail on the Tonkin and Taylor plans in Annexure C, include: Remediation Site Remediation Works (structure, approximate length, maximum height) 1A Timber pole retaining wall 13m long plus returns, 2m high anchored 1B Gabion basket retaining wall 14m long, 4m high (extension to existing gabion basket retaining wall) with anchor pins; existing damage section of gabion wall to be replaced. 2A Upgraded inlet structure (concrete apron) to existing 600mm dia culvert pipe 2B Upgraded inlet structure (riprap and concrete apron and manhole) to existing 600mm dia culvert pipe 2C Upgraded inlet structure (rock apron and headwall) and pipe extension (10m) to existing 375mm dia culvert pipe 3 In-ground palisade timber pole wall 18m long 4 Timber pole retaining wall 11m long plus returns, 2.5m high anchored 5 Timber pole retaining wall 48m long, 2m high anchored Replacement of 450mm dia culvert with 600mm dia culvert New rock riprap apron at inlet, and 5m long gabion basket outlet protection apron 6 Timber pole retaining wall 15m long plus returns, 2.5m high anchored 7 Timber pole and reinforced concrete pole retaining wall 46m long plus returns, 2m high anchored 8 Gabion basket retaining wall replaced with timber retaining wall 16.5m long, 2m high anchored 9 Palisade wall 13.5m long, poles drilled and buried below existing ground level 10 Gabion basket retaining wall 29m long, 3m high anchored 8

10 11 Reinforced concrete pole and concrete panel retaining wall 25m long, 2.5m high anchored 12 Timber pole retaining wall 15m long plus returns, 2.3m high anchored 13 Timber pole retaining wall 15m long plus returns, 2.6m high anchored 14 Culvert upgrade replace 600mm dia pipe with 1050mm dia pipe, stabilise inlet, 4m long gabion basket and 5.5m long rock apron at the culvert outlet 15 Gabion basket retaining wall 20m long, 3m high 16 Upgraded inlet structure (rock riprap) and table drains to existing 450mm dia culvert 17 Gabion basket retaining wall 15.5m long, 2m high 18 Palisade wall 48m long, poles drilled and buried below existing ground level 19 Timber pole retaining wall 20m long plus returns, 1.5m high 20 Culvert upgrade replace 450mm dia pipe with 600mm dia pipe, rock riprap inlet and outlet protection 21 Upgraded inlet structures (rock apron, headwall, and permeable rock weir) and batter slope stabilisation for two existing 450mm dia culvert pipes, and 8.3m long rock riprap apron at the outlet of one culvert. Improved roadside water table channel between culvert inverts 22 Gabion basket retaining wall 40m long, 4m high 23 Timber pole retaining wall 35m long plus returns, 2m high, anchored and palisade wall 7m long, poles drilled and buried below existing ground level 24 Timber pole retaining wall, anchored 17.5m long plus returns, 2m high 25 Upgraded inlet structure (headwall and riprap) for existing 450mm dia culvert Replacement of 450mm dia culvert with a 750mm dia culvert, with headwall and riprap at inlet Improved roadside water table channel between culvert inverts 26 Gabion basket retaining wall 78m long, 4m high and palisade wall 15m long, poles drilled and buried below existing ground level 27 Upgraded inlet structure for existing 450mm dia culvert, and refurbishment of concrete lined outlet channel, improved roadside water table channel; timber retaining wall 28 Upgraded inlet structure and provide riprap outlet apron for an existing 450mm dia culvert, improved roadside water table channel In-ground palisade timber pole wall 20m long 27. Tonkin and Taylor s plans include, for each site, sheets showing the existing site plan (slip damage) and geotechnical investigation sites, a site layout plan, cross-sections, elevations and details of the proposed remediation works, and a sediment and erosion control plan. These plans identify the legal boundary between road reserve and private properties, and, where relevant, are underlain by aerial photographs showing the location of nearby houses and access. 28. The construction works are to be contained fully within existing road reserve, except as follows: the outlet structures for the new culvert at Site 14, and for the existing culvert at Site 28, extend into the downslope properties. the inlet riprap for existing culverts at Sites 20 and 21, and earthworks at Sites 6, 7 and 27, extend into the uphill property. the anchors for the retaining wall at Site 7 extend under the uphill property. 29. The method of construction and earthworks is outlined in 7 of the Tonkin and Taylor Geotechnical Assessment (Annexure D). 30. It is anticipated that a number of sites will be worked at any one time, starting in December 2012 (pending the attainment of resource and building consents), and that the overall remediation programme will take 2-3 years to complete. 31. Individual landowners affected by works at each site will, with 5 working days notice, be advised in writing that construction is commencing. 9

11 32. All earthworks will be carried out in accordance with the Environmental Management Plan (EMP) in Annexure E. The EMP considers: 1. dust mitigation 2. sediment transport 3. erosion risk during construction 4. protection of the environment (including noise management, avoidance of polluting substances, disposal of asbestos pipes, and protection of vegetation). 5. traffic management. 33. Each work site is less than 0.3ha in area, of which less than 0.2ha will be unvegetated or disturbed during construction. Sediment traps (silt fences) will be installed downslope of each work site, and any stormwater runoff will be discharged to the vegetated slopes above the Wakapuaka Estuary. 34. Tonkin and Taylor propose the following erosion and sediment controls: silt fences (as outlined above); additional wire mesh fence where above residential land or property where this is risk of rock or debris rolling downslope; extension of culverts (via sock or similar attachment) past the area of disturbance; diversion of stream around and below the work site while working on culverts; topsoil, grass seeding and/or, on steeper slopes, planting of deep-rooted trees and shrubs. 35. The Council proposes to develop a planting strategy for land upslope of the road, as a preventive measure to reduce the maintenance requirement from silt and sediment migration onto the carriageway. The strategy will be implemented by Council within road reserve. Planting of trees and shrubs may initially involve exotic stability plants ie poplar interspersed (and later coppiced) within endemic plants suitable for the Cable Bay environs (refer DOC Living Heritage Growing Native Plants in Nelson ). 36. It is intended that at least one lane along Cable Bay Road will remain open to traffic at all times, unless required for short duration critical activities. A Traffic Management Plan will be prepared prior to works commencing on site, the content of which is outlined in the EMP. 37. The Applicant proposes that an Iwi Monitor be advised in advance of programmed earthworks at each site, affording opportunity to be present as required. The Council will enter into a protocol for Iwi Monitoring as required by those parties. 38. As the works are completed, the road pavement will be constructed alongside the retaining walls and culverts. Spill will be disposed of off-site at an NCC designated disposal site. NELSON RESOURCE MANAGEMENT PLAN Zoning and Overlays 39. Cable Bay Road is not designated in the Nelson Resource Management Plan (NRMP). The application site (including road reserve, which assumes the same zoning as land either side of it) is zoned Rural on Planning Maps 36 and 46 in the NRMP. 40. Land above assumed mean high water springs (inland from the outer or seaward edge of the esplanade reserve) is also within the following: the Coastal Environment Overlay the CEO identifies land in the coastal environment where the natural character is such that consideration needs to be given to the nature of activities (including structures or buildings) and their effect on coastal natural character values; 10

12 the Land Management Overlay the LMO identifies land sensitive to activities, such as earthworks, vegetation clearance and soil disturbance, that may cause erosion and sedimentation. 41. The Riparian Overlay extends along the margin of Delaware Bay, within the existing esplanade reserve (CT 128/190) around the estuary, and indicates coastal margins having conservation, public access, hazard mitigation or a combination of these values for esplanade purposes. No remedial earthworks are proposed within the esplanade reserve. The reserve is owned by the Council, administered by its Reserves Department. Any decisions on replanting of portions of the reserve lie with the Reserves Department, are not necessitated by remedial works to the road proposed under this application, and would be a permitted activity under the NRMP. 42. There is a landscape tree shown on road reserve but which Appendix 2 states is a pohutukawa located at 720 Cable Bay Road. The location of this tree is shown on the site plans in Annexure B, and will not be affected by the remediation works. 43. No remedial works is to occur on the seaward of mean high water springs, in the Coastal Marine Area (CMA) under the NRMP. 44. Although there are no recorded archaeological sites annotated on the planning maps on land along this side of Delaware Bay, Delaware Inlet within the CMA is identified as an Archaeological Overlay. This is a Heritage Overlay and identifies areas known to contain a high number of archaeological sites, many of which are not documented, and which may potentially be damaged by activities. 45. Delaware Inlet is also classified as a Marine Area of Significant Conservation Value (MASCV) in the NRMP. The MASCV Overlay covers areas of significant conservation value within the CMA, the values of which must be recognised and provided for as matters under Section 6 of the RMA. Delaware Inlet is of national status (Appendix 4, NRMP): Located north of Nelson, this area includes an estuary, barrier spit (tombolo), boulder bank and island. Delaware Inlet is an estuary of approximately 420ha with a low level of human impact. A large area of salt marsh located at the mouth of the Wakapuaka River supports threatened banded rail. The estuary also supports banded dotterel and variable oystercatcher Delaware Inlet is located down slope of the proposed remediation works, and is potentially part of its receiving environment. While no physical works are to occur within the CMA, the conservation and heritage values of the inlet are of relevance in managing the potential off-site effects (ie sedimentation and erosion) of the earthworks and construction programme. While not giving rise to the need for specific resource consents, this matter has been given consideration in the Environmental Management Plan in Annexure F and as an assessment matter for earthworks in the Coastal Environment Overlay. 47. The proposed remediation works also involve earthworks and culverts within freshwater water courses, and are therefore subject to the Freshwater Rules for the Rural Zone. These rules do not apply to coastal waters, only freshwater. Land Use Rules 48. The relevant land use rules are contained in Chapter 12 (Rural) of the NRMP. 49. The following table establishes compliance with various rules in Chapter 12 of relevance to the proposed remedial works: 11

13 NRMP Rule Comments Activity Status Vegetation Clearance and Soil Disturbance RUr.24 Clearance of Indigenous Forest RUr.25 Vegetation Clearance RUr.26 Soil Disturbance To the extent that there is any indigenous vegetation significant enough in size, species and canopy cover to be defined as indigenous forest, or any other clearance of vegetation or disturbance of soil within 20m of the CMA, this has already been destroyed or dislodged by the slips rather than being the result of the remedial works. No further vegetation removal of significance is required to give effect to the proposal. Any further disturbance of soil, and management of the associated effects of that, will be addressed under the earthworks rules in RUr.27. Earthworks RUr.27 Earthworks RUr.63 Land Management Overlay RUr.53 Coastal Environment Overlay - Earthworks Retaining Walls RUr.28 Buildings While the NRMP recognises the need for earthworks in maintaining roads, the proposed earthworks, retaining structures and fill will in places exceed 3m, and will be up to and over properties boundaries (Rule RUr.27.1). The height or depth of filling may also exceed 4m and will occur in the Land Management Overlay. The proposed works will all be more than 20m from the CMA. The rules provide for maintenance of existing roads in the CEO as a permitted activity. The scale of the earthworks is considered to extend beyond maintenance of the existing formation of Cable Bay Road, will occur within the Land Management Overlay, and will exceed 1.2m in excavation or fill height or depth. The retaining walls will in places be over 2m in height and are therefore defined as buildings under the NRMP. They will be ancillary to the proposed earthworks, which on the scale required is not a permitted activity. Restricted discretionary activity (Rule RUr.27.3) Discretionary activity (Rule RUr.53.3) Discretionary activity (Rule RUr.28.3), although the interrelationship between the retaining walls and earthworks is such that the assessment criteria and matters of discretion under Rule RUr.27 are most relevant to this aspect of the works. RUr.32 Building Height The highest retaining wall will be 4+m, well within the permitted height of 12m for the Rural zone. Permitted activity 12

14 RUr.43 Structures on Road Reserve RUr.50 Coastal Environment Overlay - Structures Reinstatement of the Road Carriageway RUr.33 Site Coverage by Impervious Surfacing RUr.46 Network Utility - Roads The NRMP permits structures relating to the safe use of the road, and culverts as part of the roading infrastructure. The proposed retaining walls are to provide for the safe use of Cable Bay Road, and are therefore permitted within road reserve. The NRMP permits the erection of new structures in the Coastal Environment Overlay between the road and Delaware Inlet between 636 Cable Bay Road and the Stewarts camping ground, providing the retaining walls are no closer than 20m from m.h.w.s. South of 636 Cable Bay Road some of the larger retaining walls, being non-residential structures, may exceed 20m 2 in ground area and/or 5m in height, but will be at least 20m inland of m.h.w.s Any paving of land with impervious surfacing will be to reinstate road or driveways damaged by the floods. The proposed works relate to an existing road, not a new road. They provide for remediation of the existing carriageway to the same level that pre-dated the flood event, notwithstanding any variation to the standards in Appendix 14 of the NRMP. Permitted activity Retaining structures south of 636 Cable Bay Road are controlled activities Existing use rights Existing use rights 50. The proposed remediation works has been considered comprehensively as one earthworks and construction proposal, rather than assessing the compliance or otherwise of individual site works against the NRMP requirements. 51. The works generally require resource consent under the land use rules in the NRMP as they involve earthworks (in some sites exceeding 4m in height or depth) in the Land Management and Coastal Environment Overlays, and with certain retaining walls of a height, area and/or location deemed to be new buildings or structures not fully complying with NRMP requirements. 52. With the bundling of sites and consents, the proposed remediation works (earthworks and structures) are to be assessed as discretionary activities under the NRMP. 53. The assessment criteria in the NRMP for earthworks, in particular, will form the basis of the AEE later in the application. Freshwater Rules 54. The remediation works involve earthworks and culvert placement or upgrading in several small streams or watercourses that pass under Cable Bay Road. 13

15 55. Of the culvert works identified in 23 above, Sites 2B, 5, 14 and 20 involve permanently flowing streams. The watercourses at Sites 25 and 27 are intermittent, flowing only in rainstorm events. With the exception of Site B which flows into the Wakapuaka River, all flow into the estuary. 56. These streams are deemed to be rivers under the definitions in the NRMP, and works within them are subject to the freshwater rules (Appendix 28) in the NRMP. 57. General conditions for the disturbance of river beds are contained in Rule FWr.1. The removal of vegetation and flood debris deposited in the bed of a river is a permitted activity under this rule, however flood remedial works beyond this subject to the general conditions in Rule FWr It is not intended that works on these watercourses cease during the nominated fish spawning seasons in the NRMP: the activity: - shall not affect sediment levels or vegetation in all lower tidal reaches of waterbodies during the main spawning period of inanga (15 March to 31 May); - shall not be carried out between 1 April and 15 August in all water bodies upstream of the tidal reach (which extends for a length 5 times the width of the river mouth) for the protection of koaro and kokopu species spawning habitats unless ambient levels of sediment are returned within 48 hours of construction commencing within the water body;. - shall not be carried out during the trout spawning period (1 May to 30 September) in the Maitai, Brook, Whangamoa, Wakapuaka, Lud and Teal Rivers and Poormans Stream. The slope of their catchments, size and nature of these watercourses means that they do not have a tidal reach and are not one of the nominated trout spawning rivers. They are likely to have limited native fish spawning value, although an eel was observed in the main stream (south of Site 24) during the post-flood emergency clean up works. To the extent that earthworks within the streams needs to be managed to avoid sedimentation downstream of the work sites, this is addressed through sediment and erosion control measures in the Environment Management Plan, including: the proposed diversion/piping of water around instream work sites; and extension, via sock or similar attachment, of culverts past the area of disturbed land within each work site. With this, ambient sediment levels downstream of the culvert sites should be maintained. 59. There will be no refuelling of vehicles, or storage of contaminants, within 5m of the streams. Removal of any asbestos pipes will be closely controlled under the EMP. 60. It is not considered that the works will result in the production of conspicuous oil or grease films, scums or suspended materials, any conspicuous change of colour or visual clarity, emission of objectionable odour or adverse effects on aquatic life in receiving waters, both to the waterway down stream of the work site or the estuary. Disturbance to the bed of each stream will be kept to a minimum (both spatially and with works occurring on a dry bed) so as to minimise effects on the downstream receiving environment. Use of machinery within the wetted bed of the drains will be avoided. 61. To the extent that it is relevant to these waterways, fish passage will be maintained post-construction, and their riparian margins will be rehabilitated to a state similar to that existing prior to the rainstorm event. It is considered that the proposal will meet the general conditions in Rule FWr Rule FWr.1.2 provides for the disturbance of the bed of a river for the purpose of maintaining peak flow capacity, surrounding land stability and public safety as a controlled activity, to be considered as a non-notified application. Given that the proposed works within the streams are part of the overall remediation package for Cable Bay Road, it is considered that they fall within the scope of this rule. The works meet the conditions of Rule Fwr.1.2 in that (i) the general conditions in Rule FWr.1.1 are 14

16 met, (ii) any plantings will be native or exotic species suitable to the conditions, (iii) any rocks used will look similar to those occurring naturally in the area and (iv) the works will be undertaken in such a way to maintain habitat values. 63. Control is reserved over: (i) Disturbance to river banks this will be limited to sites immediately either side of or within road reserve. (ii) The timing and duration of works In-stream works will occur progressively in line with construction at each work site. The amount of time to complete any individual culvert upgrade will need to be minimised to avoid disruption to road traffic. (iii) Method of undertaking the activity refer to the EMP, and the detailed design on the engineering plans. (iv) The avoidance, remedying or mitigation of adverse effects and any alternative options - refer to the EMP, and noting the scale and purpose of the proposed upgrading works. (v) Maintenance of existing structures, including...roads the very purpose of these works is to remediate Cable Bay Road. 64. Rule FWr.4.1 provides for the replacement of any lawfully established structure (and associated deposition and armouring) on or over the bed of the river, and removal of any existing structure on or over the bed of a river, as permitted activities. Because the existing culverts do not have resource consents, the relevant rule is FWr The placement of new culverts and associated armouring is covered by Rule FWr.5. The culvert designs are included in the engineering plans in Annexure C, they will be designed to Q15, they will be set below the bed level of the streams, and they are not associated with residential development, however the catchment upstream of each of the culverts may be excess 10ha, and some of the culverts will be greater than 20m in length. The proposed works are a controlled activity under Rule FWr The culverts will meet the conditions in Rule Fwr.5.2 they will meet the general conditions in FWr.1.1, they will be positioned to maintain the gradient and alignment of the streams, they will be armoured and maintained to avoid blockage by debris, and they will be designed to Q The Council has reserved its control over the following matters under Rule FWr.5.2: (i) Damage to indigenous vegetation and habitats The works are to occur on streams under and immediately adjoining Cable Bay Road, replacing or upgrading existing culverts and their intake/outlets. There is no indigenous vegetation or habitats of significance at any of the sites. (ii) Disturbance to river banks and river beds Disturbance to the bed of the streams, and any downstream effects ie sedimentation, will be kept to a minimum through a combination of works occurring during dry weather conditions, within a dry bed, and for only a short duration. Physical works will be limited to an area including and approximately 5m-10m either side of the road, and the intake/outlets to the culverts will be appropriate armoured to protect the new structures. Any effects on water quality or clarity will be minor and temporary, confined to the construction period. (iii) Adverse effects on fish passage Fish passage will be maintained via the culverts. (iv) Flood capacity Tonkin and Taylor have designed the proposed remedial works to improve the functioning and capacity of the culverts to cater for high rainfall events, including as some works will involve the installation of large diameter pipes, and inlet structures will be enlarged at other sites, to improvement road stormwater drainage. 68. The upgrading and replacement of culverts and their intake/outlet structures within the stream bed at those 6 sites identified in 55 above is a controlled activity under the NRMP. 15

17 ACTUAL OR POTENTIAL EFFECTS ON THE ENVIRONMENT 69. Section 88 of the Resource Management Act states that any application for resource consent must be accompanied by an assessment of effects on the environment, prepared in accordance with the Fourth Schedule of the Act. 70. Such assessment must be commensurate with the scale or significance of the effects on the environment that may arise with the proposal. 71. Use of the words effect, environment and amenity values in this assessment of effects on the environment should be interpreted as follows, in accordance with Sections 2 and 3 of the Resource Management Act 1991: Effect... includes- (a) Any positive or adverse effect; and (b) Any temporary or permanent effect; and (c) Any past, present, or future effect; and (d) Any cumulative effect which arises over time or in combination with other effectsregardless of scale, intensity, duration, or frequency of the effects, and also includes- (e) Any potential effect of high probability; and (f) Any potential effect of low probability which has a high potential impact. Environment includes (a) Ecosystems and their constituent parts, including people and communities; and (b) Any natural and physical resources; and (c) Amenity values; and (d) The social, economic, aesthetic and cultural conditions which affect the matters stated in paragraphs (a) to (c) of this definition or which are affected by those matters. Amenity values means those natural or physical qualities and characteristics of an area that contribute to people s appreciation of its pleasantness, aesthetic coherence, and cultural and recreational attributes. 72. The plans, engineering design, geotechnical assessment and environmental management plan prepared by Tonkin and Taylor Ltd (Annexure B E), and the mitigation measures incorporated in the design of the remedial works and/or the recommendations contained in their reports, form a substantial part of this AEE. The consent authority must take into account any mitigation measures proposed as part of the application which will impact on the potential effects of the proposed earthworks, retaining walls and in-stream works. 73. In making an overall judgement under Section 5 (sustainable management of resources) of the Resource Management Act, the consent authority must consider the positive effects of the proposed activities. The whole purpose of the works is to remediate flood / slip damage to reinstate the carriageway traffic flow on Cable Bay Road. Arising from this will be related benefits for downslope properties and the carriageway itself in minimising the potential risks from further instability of unremediated slips and under-capacity culverts. The potential effects on the environment of not carrying out the remedial works the effects on road users, property owners and structures, and the receiving environment particularly downslope of the sites may be significant and more than minor. 74. Section 104(3) of the Act prevents the Council from taking into account the effects on any persons who have given their written approval to an application. The Applicant is consulting affected parties (those property owners downslope of each of the work sites, and the farmer above) in the course of this process. Any written approvals obtained will be submitted to Council as part of the application (Annexure G), and must be taken into account in assessing any actual or potential effects on neighbours. 16

18 75. The actual or potential effects of the in-stream works (culverts) has been addressed above in terms of the matters over which the Council has reserved its control as controlled activities under the NRMP. Any adverse effects of those works on in-stream values and the downstream receiving environment (including the estuary) will be temporary and less than minor. 76. There will be effects of construction for residents, namely: - noise and amenity effects associated with heavy traffic, use of machinery and work practices; - disturbance to traffic flows on Cable bay Road; - potential dust nuisance and vibration. These will be managed in accordance with the EMP, and will be temporary (confined to the duration of works at each of the sites). For that reason, the effects of construction will be no more than minor. 77. In assessing the environmental effects of the proposed earthworks, it is relevant to take into account the existing environment when considering issues of sedimentation and erosion, visual impacts, access for residents of and visitors to Cable Bay, and potential impacts on neighbours. The proposed works, if appropriately designed and constructed, will address the issues presently experienced by land owners and road users, including land stability, aesthetic or amenity values and the traffic impacts of a badly damaged road and its environs. 78. The assessment criteria in Rule RUr.27.4 for earthworks are relevant to the assessment of the effects of the bulk remedial earthworks and related retaining structures at most of the 28 sites: i) Loss of topsoil or movement of soil downslope The movement of topsoil and soil downslope has already occurred as a result of the December 2011 rainstorm event. The proposed works will prevent a continuation of this slope failure, and with construction undertaken in accordance with the EMP so as to minimise the potential for further loss of material downslope during construction. ii) iii) iv) Potential for slope failure The works are to remediate land suffering existing slope failure. The design has been preceded by geotechnical investigation of sub-surface conditions, and the retaining walls and stormwater controls have been engineered to avoid or mitigate the risks of future slope failure. Damage to structures or adjoining property A majority of works are to occur within road reserve. The engineering designs have been cognisant of the location of structures, houses and property access in the vicinity and downslope of the earthworks and new retaining walls. Mesh fences are proposed below the work sites where there are residence downslope of the works. Soil and vegetation entering rivers and coastal waters The proposed work sites are set back from the coastal margin, and any rivers of significance. There will be no significant disturbance to vegetation, most of which within the work areas has already been affected by the slips themselves. v) Damage to instream and coastal habitats This has been addressed in relation to the instream works (culverts). Sediment and erosion control measures are also outlined in the EMP. vi) Adverse effects on catchment stream flow - This has been taken into account by Tonkin and Taylor in designing the culvert and intake upgrade and replacement works, and in stormwater management and culverts required at the other sites. 17

19 vii) viii) ix) Bank and coastal erosion Due to the location and nature of the earthworks and retaining walls, there will be no river bank or coastal erosion as a result of these works. Duration of bare soil exposure to wind and rainfall The slip sites have already been exposed for close to a year and, given the duration of the overall remediation project, that will remain so as the works programme is anticipated to take 2-3 years. As each site is completed, it will be regrassed and steeper sites replanted in accordance with the planting strategy contained in the EMP. Water quality, including suspended sediment load and increased stream bed load water quality will be maintained given the location of the works and the proposed sediment and erosion control measures in the EMP. x) The method and timing of the activity xi) The area to be cleared at any one time xii) The provision of structures to control soil erosion and sedimentation xiii) The timing and techniques for revegetation These matters are all addressed in the EMP in Annexure E and, for sediment and erosion management, the plans in Annexure C. xiv) xv) xvi) xvii) xviii) xix) xx) xxi) xxii) xxiii) xxiv) The long term management of the land cleared The land affected by these works will be managed by the Council as road and/or road reserve, including as the Council will have an obligation to monitor and maintain the structures under its resource consents. The provision of appropriate resources to ensure that adverse effects arising from emergency and unforeseen circumstances are controlled or mitigated Both Council and NZTA funding has been committed to complete the proposed works. Visual effects The retaining structures will be most visible on their downslope side, potentially from residential properties and the coast. They will have limited visibility from the road itself. They will weather in appearance over time, and in some instances be screened as plantings establish. They will also be sited to the rear, and not without the main outlook from, residences. The longer term visible impact of the works will be minor. Impacts on privacy and the admission of daylight and sunlight to neighbouring sites The top of the retaining walls are at existing level of the road, and within proximity of its edge prior to the slips occurring. Any impacts on privacy or sunlight will be unchanged from the preexisting conditions. The values set out in Appendix 6, Table 6.1 (riparian and coastal margins) n/a The matters in Appendix 9 (landscape components and views) n/a The matters in Appendix 4 (marine ASVC overlays) The effects of the works will be managed so as to avoid any adverse impact on Delaware Inlet. The effects of the earthworks in relation to primary and secondary flood flow this has been incorporated within Tonkin and Taylor s designs, and with enhanced secondary flow paths across Cable Bay Road. Control of noise Control of dust Traffic and access issues These matters are addressed in the EMP, including as a Traffic Management Plan is required. It is proposed that access on Cable Bay Road be maintained at all times throughout the 18

20 construction programme, except for very short-term critical works where authorised by the engineer. 79. Any effects on cultural values will be addressed by the inclusion of an Iwi Monitor. Protocols will be put in place to cease work and undertake appropriate action in the event of an archaeological find. 80. Effects on critical infrastructure, namely the fibre optic cable, have been addressed in the site investigations and EMP. 81. Providing the designs and recommendations made by Tonkin and Taylor, included in their plans, Geotechnical Assessment and Environmental Management Plan, are adopted any adverse effects on the environment as a result of this proposal can be adequately avoided, remedied or mitigation so that the effects will be no minor than minor. ALTERNATIVE SITES AND METHODS 82. The actual or potential effects on the environment arising from this proposal will be no more than minor. The Applicant is not required to consider alternative sites or methods under the Act. 83. Notwithstanding that, the proposal relates to a specific locality and section of road affected by the December 2011 rainstorm event. The matter of alternative sites is irrelevant in these circumstances. 84. The remedial works have been subject of detailed geotechnical investigation and engineering design. They are considered the most appropriate and geotechnically suitable means to remediate each of the affected sites. 85. It is acknowledged that the works will take some time to complete, based on the need to keep the road open at all times and for resourcing reasons given the number of remediation sites. MITIGATION MEASURES 86. Mitigation measures have been incorporated within the design and scale of the works and structures proposed, and in the Environmental Management Plan. No further mitigation measures are considered necessary in managing the potential effects of the proposal. MONITORING 87. Any consents or permits issued in respect of this application will be monitored in accordance with Council s standard compliance monitoring function. The Project Engineer will also take a specific interest in supervising and monitoring the standard of work undertaken at each of the sites, in accordance with his design. 88. Given the scale of the works and duration of the remediation programme, it may be appropriate to include a Section 128 review condition to consent. CONSULTATION AND AFFECTED PARTY APPROVALS 89. The Council has consulted with the local Cable Bay community through letter drop and public meeting, and through one-on-one consultation about the proposed works and their design affecting sites above individual properties. 90. The Applicant is consulting all affected land owners and Iwi with a hope that written approvals to the proposal may be obtained. 19