Richmond Residential Red Zone: Summary of Technical Information As at Area ID: 15A, September 2016 15B

Richmond residential red zone: Summary of Technical Information as at Area ID: 15A, September 2016 15B

Purpose of this document:

The following information provides a summary of the local environmental values, conditions and potential hazards. The information has been gathered using the best available technical data held by a number of agencies and organisations. It does not identify or assess land use options or the feasibility of land uses. The information in this document is not, and should not be interpreted as, a pre-determination, recommendation or decision about future use. No decisions regarding the future use of this land have been made.

Overview of Richmond residential red zone (Area 15): Area 15 is approximately 27 hectares in area and adjoins River Road along the margins of the Ōtākaro/Avon River from Banks Avenue to the east and Fitzgerald Avenue to the west. To the north and west, Area 15 adjoins existing urban areas. This Area had a number of significant home gardens with mature trees some of which are still being tended.

Area 15 is susceptible to a number of natural hazards, which can potentially occur either in isolation or collectively leading to a number of adverse cascading effects. The risk from many of these hazards will increase over time due to the accelerating effects of sea level rise. The area is particularly prone to lateral spreading. Land contamination may be an issue for much of the site.

Location Map

Natural Environment and Cultural Setting and Features

Natural Environment Adjacent to the Ōtākaro/Avon River and Tributaries Significant Ecological Site (site ID no. SES/LP/24) in Chapter 9 (Natural and Cultural Heritage) Appendix 9.1.4.1 of the notified version of the proposed Christchurch Replacement District Plan1. This site is significant because it 'supports At-Risk fish species including their migration routes, and supports indigenous vegetation and avifauna that is representative of the Low Plains Ecological District'. The site includes Dudley Creek. Located at the south western corner of Harvey Terrace and Templar Street is a Significant Tree (Black Locust) – identified as Tree ID No. T139 in Chapter 9 of the notified version of the proposed Christchurch Replacement District Plan. The adjacent Ōtākaro/Avon River main stem has a significant yellow flag iris (Iris pseudacorus) infestation. This plant is a weed that forms dense tuberous mats excluding native wetland plants, choking wetlands, waterways and may degrade whitebait spawning areas. The plant is designated an “unwanted organism” under the Biosecurity Act and is identified as a pest by ECan.

Waterways Adjacent to Ōtākaro/Avon River (which is classified as a Downstream River) with a 30m setback and Dudley Creek (Upstream River) with a 10m setback2 as per Chapter 6 (General Rules and Procedures) of the notified version of the proposed Christchurch Replacement District Plan3. A small section of the lower reach of Dudley Creek flows through Area 15A. Christchurch City Council’s vision for the Ōtākaro/Avon River catchment is set out in the following document: http://ccc.govt.nz/assets/Documents/Environment/Water/Avon-River-Catchment- Vision-and-Values.pdf

Groundwater – Current median groundwater depth is predominantly deeper than 1m below depth below surface surface, except for lower-lying terrace at the Dudley Creek confluence (0.5 – 1.0m depth). Median groundwater depth with 1m sea level rise is anticipated is to be predominantly deeper than 1m below surface, except for the lower-lying terraces at the Dudley Creek confluence (at the surface, 0.0 – 1.0m depth) and Flesher Ave (0.5 – 1.0m depth).

Coastal Marine Area Outside the Coastal Marine Area.

Public Facilities Adjacent to Banks Ave School and in close proximity to the Shirley Boys High campus. Avebury House is located within the adjoining Avebury Park. The tennis courts below Harvey Terrace at the western end of Area 15.

1 The Independent Hearings Panel is yet to issue its decision on Chapter 9 hence the provisions and related maps are subject to change 2 A resource consent is required from the Christchurch City Council to fill, excavate or build within setbacks 3 The Independent Hearings Panel is yet to issue its decision on Chapter 6 hence the provisions and related maps are subject to change 2

Reserves Adjacent to Avebury Park, a Garden and Heritage Park (9,124m2) which has a significant cluster of mature trees, and is zoned Open Space Community Parks under the proposed Christchurch Replacement District Plan. Also adjacent to Richmond Park which is a sports park (37,529m2), and reserves alongside the river.

Mana Whenua / The whole of Area 15 is shown as a culturally significant zone and is part of a larger Ngāi Tahu Interests Ngāi Tūāhuriri takiwā area of interest. Mana Whenua and Ngāi Tahu strongly recognise the relationship of this area with Te Ao Tūroa (Natural Environment), ecological values and the water. This area also has significant Mahinga Kai values

Archaeology and Chapter 9 (Natural and Cultural Heritage) of the notified version of the proposed Heritage Christchurch Replacement District Plan4: There is one heritage feature in Area 15B, being a cottage on River Rd (now removed). A Heritage Setting in Avebury Park adjacent to Area 15A is noted. New Zealand Archaeological Association: There are six recorded European archaeological sites, predominantly in Area 15B and the south end of Area 15A. Five of these relate to historic house sites and one is not identified. Material evidence of Māori occupation has been found in this locality in the past. There is a recorded Māori archaeological site in the vicinity of Banks Avenue and there is an area of potential Māori archaeological sites near Dudley Creek. Accordingly, there is potential for further items or sites of archaeological value to be discovered.

Special or Other The house in Templar Street formerly owned by Bill Sutton, while not a listed Features heritage feature, is considered to have value for its association with an important Canterbury artist.

Hazards

Coastal Hazard The lowest-lying part of Area 15A (north of Medway St) is mapped as susceptible to coastal inundation and would be subject to coastal inundation in a one in 50 Coastal inundation year storm taking into account sea level rise within the next 50 years. The area Coastal Erosion may potentially be prone to coastal erosion as it is susceptible to daily tidal influence taking into account sea level rise within the next 50 years. This is Tsunami anticipated to be a passive erosion arising from daily tidal flow along the bank SLR = Sea Level Rise margins. assumed to be 0.4m The existing average ground elevation above perigean high tide level is 1.7m in over the next 50 Area 15A and 2.6m in Area 15B. Most of the land is within ±1.0m of these average years and 1m over levels. the next 100 years. For more information on coastal hazards, Christchurch City Council have a web page dedicated to coastal hazards which can be accessed at:

4 The Independent Hearings Panel is yet to issue its decision on Chapter 9 hence the provisions and related maps are subject to change. 3

http://www.ccc.govt.nz/environment/land/coast/coastalhazards/ Information on tsunami risk is available at: http://ecan.govt.nz/advice/emergencies-and-hazard/tsunami/Pages/south- american-tsunami-modelling.aspx

Flooding Flood modelling shows major flowpaths exist within 150m of Dudley Creek confluence at Banks Ave, within 40m of river edge at bends in river at Glade Ave ARI = Average and Lois Pl, within 80m of river edge to the south of Harvey Tce, and within 25m of Recurrence Interval the river edge elsewhere. Lower terrace areas fall within proposed Christchurch Replacement District Plan Flood Management Area (200 year flood). Some small areas at the river edge and Dudley Creek confluence fall within the District Plan High Flood Hazard Management Area (500 year flood and more than 1m depth). Raising the land in the lower terrace areas above flood level, would likely worsen flooding elsewhere. In the higher terrace areas above the 200-year flood level fill would not be required for flood mitigation purposes. Depth of flooding for 50 year flood event with 1m sea level rise may be 0.5 to 0.7 on low lying areas and over 1.0m by Banks Avenue. Depth of flooding for 200 year flood event with 1m sea level rise may be 0.1 to over 1m on the lower terrace levels. For further information on flood hazards refer to the: ‘Flooding’ and ‘District Plan’ pages on the Regenerate Christchurch webpage.

Geotechnical In Area 15 the main geotechnical constraint is the potential for severe area-wide lateral spreading due the long thin nature the area that is exposed to open river Earthquake induced frontage. Liquefaction, lateral spreading For further information on geotechnical issues in this area refer to the following geotechnical summary: Subsidence (consolidation) http://ceraarchive.dpmc.govt.nz/documents/flat-land-geotechnical-summaries

Contamination Only two known sites on the Hazardous Activities and Industries List (HAIL) (identified as activities), but these are likely to be only small domestic tanks. The LLUR Listed Land Use age of dwellings means that soil contamination from asbestos is possible. Register The potential for shallow fill alongside the river was noted. Recent investigations have identified that some areas of shallow fill contain contaminated materials.

Infrastructure

Wastewater Wastewater mains (including the Northern Relief) cross the residential red zone from North Avon Road to Evelyn Couzins Ave, connecting to the pumping station on the opposite side of the Ōtākaro/Avon River. Wastewater mains also travel along Fitzgerald Ave and on Heyward Terrace.

Water supply Water supply mains travel north/south on Fitzgerald Avenue and Stanmore Road. There are pump stations at Glade Ave and Lois Place.

Stormwater Stormwater mains cross Area 15 at Harvey Tce, from Vogel Street to Swanns Rd management and from North Avon Rd. These all service the Richmond area, discharging to the Ōtākaro/Avon River. In June 2015, Christchurch City Council lodged a resource consent application with Environment Canterbury for the discharge of water and contaminants to land and water, including coastal water, from the existing and future reticulated stormwater network. The proposal includes all reticulated networks within Christchurch City and Banks Peninsula. Parts of the residential red zone have been identified under the Ōtākaro/Avon Stormwater Management Plan (appended to the resource consent application) as being potentially developed as a detention storage basin, first flush basins and wetland to service the adjacent existing urban area. The construction of such facilities will depend on the outcome of decisions relating to the future use of the residential red zone. Submissions have closed on the application and a hearing is expected to proceed after February 2017. Further details can be found at: http://ecan.govt.nz/get-involved/consent-projects/ccc- stormwater/pages/notification.aspx

Transport Area 15 is traversed by two key north/south roads. Under the proposed Christchurch Replacement District Plan, Fitzgerald Avenue, has been classified as a Major Arterial route and forms the western boundary of Area 15. Under the new Christchurch District Plan, Stanmore Road is a Collector Road. Swanns Rd is similarly categorised as a Collector road, linking to the bridge across to Avonside Dr and Retreat Rd and providing an east/west connection. The catchment of this route are now predominantly the flat land recovery areas. Dudley Creek Bypass (not mapped) to be built along Medway Street through Area 15 to the Ōtākaro/Avon River. A Major Cycle Route (“Avon-Ōtākaro Route”) is proposed to follow a route on the true right bank of the Ōtākaro/Avon River, along Heywood/Draper/Swanns and River Rd (south of Swanns Rd). More information on the Major Cycle Routes can be found at: http://ccc.govt.nz/transport/cycling/major-cycle-routes/developing-the-major- cycle-routes/