MISSION STATEMENT Merging agricultural processes within an urban fabrication: retaining the land’s sustainability and ecological values of Puhinui whilst providing urban space for the rising Auckland population.
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Contents CONTEXT Urban Growth Introduction to Puhinui Surrounding Settlements Our Rationale
3 4 5 6
ANALYSIS Slope Hydrology Land Use Capability Existing Agricultural Values Vegetation and Ecological Areas Cultural Considerations Intersecting Infrastructure Industrial Influences Development Constraints
7 8 9 10 11 12 13 14 15
DEVELOPMENT Design Driver: Multiple Nuclei Model Development Strategy Strategy Dissection Density Estimations
17 18 19 20
CONCLUSION
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REFERENCES
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Urban Growth Along with the rest of the world, Auckland City is experiencing urban intensification; an estimated 1 million people are expected within the city’s limits in the next 30 years. This puts pressure on New Zealand’s largest city to redevelop its strategies for urban growth and planning, in order to successfully establish 400,000 new homes while maintaining an urban model that is considered both ‘liveable’ and sustainable. In response, the Auckland Unitary Plan aims to acheive a liveable, sustainable city by advocating the model of a compact city - avoiding urban sprawl and acheiving sustainable growth by concentratng population density within the proposed urban limits of the city. Our focus is to explore an alternate model of urban development, testing the theory of horizontal urbanisation outside of the proposed urban limits.
AUCKLAND
PUHINUI
SCALE: 1:250,000
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Introduction to Puhinui
Puhinui is presently a 1100 hectare rural backdrop in South Auckland. Situated on a peninsula that extends into the Manukau Harbour, the area is consistant in the coastal characterictics of the Auckland Ithsmus. The landscape is comprised of small pockets of agricultural and rural land that border commercial and residential areas, the result of an accumulation of physical and cultural processes acting in the area. A brief investigation into the site’s topography reveals a relatively flat landscape prominent in large open spaces of paddock areas, fields, shelter belt planting, outstanding outlooks, and low density rural housing. The Puhinui area faces significant pressure for urbanisation due to its close proximity to the Auckland International Airport and large adjacent urban centres.
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Surrounding Settlements
Puhinui is situated South of Auckland’s current Metropolitan Urban Limit line, and is approximately 23.7km away from Auckland’s CBD. Several major towns of the Manukau region lie adjacent to the development site, including Mangere and Papatoetoe. According to the 2006 census, Puhinui has a small population of 3, 500, while the whole of Manukau is home to approximately 283, 000 people. 5
Our Rationale The Puhinui landscape is a primary agricultural base for Auckland City – siting one of the last remaining food production areas close to the CBD. Values of rural land tend to be overlooked when planning new suburban areas, as taking over vast ‘empty’ landscapes is regarded as the only answer for a city requiring more space for sprawl. However productive rural land is also the key to keeping our city alive – a rising population means an increased need for local food productivity. Thus our objective is to analyse both existing and potential features of the site. Taking into consideration the agricultural processes and ecological habitats present, we aim to develop an urban strategy for Puhinui that will merge agriculture within a new urban realm.
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Slope Analysis Development on slopes of >15o can result in high erosion rates and the compound sedimentation of waterways, and should thus be avoided when planning a suburban subdivision. As the map illustrates in red, these steeper slopes are predominantly along the coastal edge and upper tributaries of streams on site â&#x20AC;&#x201C; providing a potential for the re-vegetation and enhancement of riparian edges whilst protecting the steep land from intense urban development. The rest of the Puhinui landscape largely sits at <4o, a gentle slope rendering the land suitable for both urban housing developments and agricultural processes.
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Hydrology Puhinui is made up of several catchments that drain naturally into the surrounding streams and rivers, subsequently all feeding into the Manukau Harbour. Auckland Council has already identified the Harbour and three key streams (Puhinui, Pukaki and Waokauri) as Significant Ecological Areas, in recognition of the high habitat values these water systems support. Therefore we have shown all existing streams on site with a proposed 15m (per embankment) vegetative buffer which will help to sustain the rich diversity of ecological habitats provided by the water systems, and protect them from urban development.
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Land Use Capability Using the LUC assessment of rock types, soil slope, erosion severity and vegetation presently on site, we can demonstrate the key areas of highproducing land with low to moderate limitations within Puhinui. Our aim is to preserve the suitability of these areas for horticulture and pastoral farming by retaining as much of this land as possible amidst the development of residential areas.
SCALE: 1:30,000
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Existing Agricultural Values As illustrated on the map, Puhinui is currently an open arable landscape which utilizes the good soils discovered in our Land Use Capability assessment. There are three key types of agricultural processes occurring on site, with pastoral farming being the most prevalent and occurring on ‘low limitation’ soils. Perennial cropland and short-rotation cropland are both found in pockets of land made up of ‘no limitation’ and ‘low limitation’ soils. This indicates that it is possible for both types of cropland to be re-distributed and established on other areas of the landscape providing the arable soil classification matches the two mentioned above.
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Vegetation and Ecological Areas The southern peninsula of the site is Puhinui Reserve, a protected wildlife refuge for migratory birds as well as native tree species including kanuka, kahikatea and rimu. Majority of the coastline here is covered in mangroves and the last large area of undisturbed saltmarsh remaining in the Manukau Harbour - which is currently protected by the existence of the reserve. Mangrove ecosystems extend up along the rest of the sites coastal boundary, providing existing green corridors on these edges. Puhinui is a relatively undeveloped landscape, and this provides an opportunity for us to establish, and in some areas protect and enhance, a strong network of ecological green corridors both on land and along the coast.
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Cultural Considerations Tangata whenua are the kaitiaki (guardians) of the Manukau Harbour and adjoining lands, where the harbour was once used as an important hub for fishing and shellfish gathering by maori. Evidence of this is seen via the midden sites dotted along the coastline of Manukau. More specifically, the Puhinui region was occupied for several generations by the Waiohua tribes, whose strong ancestral associations with the landscape still remain today in the form of waahi tapu areas, pa sites, and modern kianga. It is essential that we preserve these maori heritage zones in order to maintain the important relationship tangata whenua hold with their ancestral lands. Other heritage zones on site to be aware of include the Manukau Memorial Gardens and five unique geological sites, three of which have been deemed Outstanding Natural Features in the Unitary Plan.
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Intersecting Infrastructure The Puhinui landscape is bound by the South-western Motorway (SH20) to the East, while Puhinui Road (SH20b) cuts through the centre of the site. These main arterial routes provide a good foundation from which to establish smaller road networks within a suburban setting, allowing prospective residents and workers accessibility to both the motorway and Auckland Airport. A rail line is situated in the neighbouring suburb of Papatoetoe, providing a link to Aucklandâ&#x20AC;&#x2122;s expanding public transit system.
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Industrial Influences Puhinuiâ&#x20AC;&#x2122;s close proximity to the Auckland International Airport (on the west) and one of Papatoetoeâ&#x20AC;&#x2122;s commercial zones (on the east) means there are fixed industrial influences currently acting on the site which will restrict how and where the landscape can be developed residentially. The red zone on the map indicates the path where aircraft noise will be the loudest, showing where we are unable to situate residential housing. Prospective commercial buildings can be constructed in this zone but are limited to an 8 metre maximum height restriction, and also require particular acustic insulation to ensure the outside noise level inside each building does not exceed 40 decibels when all windows and doors are closed.
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Development Constraints A post-analysis look at Puhinui has revealed several limiting factors that will directly affect the planning of an urban development area, shown in summary on this exclusions map. Limiting factors include airport noise levels, tangata whenua values, location of the landâ&#x20AC;&#x2122;s water-ways, outstanding geological features and protected open reserve land - representing all the areas we have deemed unfit for urban development within Puhinui.
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Design Driver: Multiple Nuclei Model The exploration of a Multiple Nuclei Urban Model is the design driver behind our proposed development strategy. Our intention is to be able to create a selfsufficient urban village in a polycentric environment. A Multiple Nuclei model is an ecological urban model based on planning cities around multiple nodes of activity, rather than sprawling out from one focal point (eg. Aucklandâ&#x20AC;&#x2122;s current CBD). The idea behind this is to create areas of different activities that are appropriate to each othersâ&#x20AC;&#x2122; functions, and over time the nodes begin to merge to create a single urban area that allows an even spread of both land and urban resources amongst the sprawling city. The diagram shows an example of a Multiple Nuclei urban model, where there are several different nodes located on the landscape which are circulated respectively by commercial zones, and high, medium and low density residential areas. Using a similar model for Puhinui will ensure an even distribution of urban resources in the area while retaining sustainable communities and exisitng land ecologies. 17
Commercial Zone
High Density Residential
Medium Density Residential
Low Density Residential
Development Strategy SCALE: 1:30,000
Using the Multiple Nuclei model, we have located our main commercial node towards the centre of the Eastern fringe of Puhinui, extending the current industrial and commercial area that exists in Wiri (on the otherside of the motorway). A second smaller node is located approximately 14 ha to the Southwest of the initial hub. Both nodes are surrounded by high density housing, progressing to medium density housing which extends all the way to the Puhinui Reserve boundary (refer to map). The addition of a second main transport route running through these urban areas and adjacent to the current Puhinui Road, will provide direct access to the new urban and commercial area for residents, workers and passer-byâ&#x20AC;&#x2122;s alike. The development of new roading infrastructure also allows the opportunity for a proposed light rail link to the airport which can be formed on the existing Puhinui Road. Low-density housing will be located around the rim of Crater Hill - adjacent to Mangereâ&#x20AC;&#x2122;s existing urban zone. This will be zoned as Residential 3 under the Auckland Unitary Plan, allowing the Outstanding Natural Feature status of Crater Hill to be preserved. Puhinui Reserve will be maintained and protected, with several new urban reserves created on Crater Hill and extending from the Manukau Memorial Gardens - creating green space for wildlife and people alike, as well as enhancing native planting and trees in Puhinui. The important agricultural productivity of the landscape will be preserved, with majority of current productive areas kept for agricultural processes, as seen on the map. 18
Development Strategy Dissection 1. Urban Processes
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As per our urban model strategy, urban developments begin with the two commercial nodes (in red). Residential areas are then fabricated surrounding the nodes - providing easy access for residents to the ammenities they require. Immediately surrounding the hubs are high density areas in the form of terraced housing and apartment blocks. Circulating outward from these are medium density areas of single dwelling properties. Low density housing (single dwellings on 600m2 plots) are located further north on site - one area extending from an existing urban centre (Mangere). The housing here surrounds Crater hill, and thus is fully buffered with planting to ensure the characterictics of the crater are preserved. Two smaller pockets of low density housing are located on coastal edges providing ‘desirable’ housing areas for more up-market home buyers.
2. Agricultural Processes
The large northwestern portion of the site will remain as agricultural land, with the redistribution of short-rotation and perennial croplands to sit between existing pastoral grassland. As discovered in our analysis, this area has the best arable qualities, therefore is an ideal site to continue agricultural processes. This move will ensure the sustainability of the rural area is retained, and will provide a historical link to Puhinui’s productive past, as well as help to provide a secure food source for Auckland’s increasing population.
3. Ecological Processes
A proposed series of green infrastructure on the site will ensure the ecology of Puhinui continues to flourish, and includes a rejuvenated buffer zone of at least 15m around the entire coastal and estuarine edges. This will maintain and enhance biodiversity and habitats while mitigating the effects of runoff from the agricultural and urban landscapes. Establishing green corridors throughout the site in the form of protected reserve land and vegetated shelterbelts will encourage more wildlife habitats and thoroughfare, as well as proivde visual and interactive green amenities for people. The use of these green corridors also supplements the aesthetic quality of the area, allowing dense residential zones to be merged with the surrounding natural landscape.
Density Estimations After deciding where residential development should occur on site, settlement densities can be calculated to determine how many dwellings, and therefore people, can be accomodated for each of the density zones (high, medium and low).
High
Proposed Development Type: High Density
Total Population Accommodated:
Number of Dwellings:
30% of allocated high density area will be 4 storey apartments, housing 2.5 people @ 150m2 plot sizes.
340 apartments at 5 ha ground level (1360 total apartments if each ground plot rises up 4 storeys)
3,400 people
50% of allocated area will be terraced dwellings, housing 3.5 people @ 200m2 plot sizes.
1,600 houses
32 ha
5,600 people
20% of area will be services such as roads, shops, cafes etc 339 apartments at ground level (1356 total apartments if each ground plot rises up 4 storeys)
Medium
Low
Total area in Hectares:
Dwelling Parameters:
Medium Density
Single Dwellings, housing 3.5 people @ 300m2 plot sizes
2,500 houses
80 ha
9,000 people
Low Density
Single Dwellings, housing 3.5 people @ 600m2 plot sizes
1,300 houses
80 ha
4,600 people
Total Estimated Population 22,600
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Conclusion Our initial stance towards this project was to investigate how significant site characteristics can be preserved or remediated to ensure the land retains its character while also providing urban development connections. Through our research and analysis it became clear that high soil quality provides for the rich agricultural processes that dominate Puhinui. Agriculture is an essential industry which is fast becoming undermined by urban development in Auckland City, so we decided it was in our best interests to preserve as much of this productive land as possible when designing the development growth strategy. This led to the evolution of our mission statement Merging agricultural processes within an urban fabrication: retaining the landâ&#x20AC;&#x2122;s sustainability and ecological values of Puhinui whilst providing urban space for the rising Auckland population. The location of Puhinui to Aucklandâ&#x20AC;&#x2122;s largest port provided sufficient reason to maximize development where possible on site, and therefore development to become its own centric environment. Looking at the Multiple Nuclei Urban Model, we devised a centralized development strategy that involves commerical, high, medium and low density areas radiating from two central nodes/transport hubs. This allows an even spread of resources amongst the differing zones in the city. Residential development is situated on land we deemed most ideal, while pockets of agricutural land have been re-distributed and established predominantly on the western side of the site. We have also enhanced the ecology of the site through green infrastructure in the form of vegetated buffers and shelterbelts, as well as the creation and preservation open reserve land and habitats. 21
References BACKGROUND INFORMATION AND STATISTICS: Auckland Unitary Plan, Auckland Council Document. Retrieved from http://www.aucklandcouncil.govt.nz
Preparation of a Structure Plan for Puhinui. Auckland Council Document. Retrieved from http://infocouncil.aucklandcouncil. govt.nz/Open/2014/02/AUC_20140213_AGN_4737_AT.htm
Puhunui â&#x20AC;&#x201C; Mangere Mitigation. Auckland City Council Document. Retrieved from; http://www.aucklandcity.govt.nz/council/ documents/districtplanmanukau/text/chap17.3mangerepuhinu.pdf
Puhinui Communuity Profile. Statistics New Zealand. Retrieved from; http://www2.stats.govt.nz/domino/external/web/comm profiles.nsf/printing/1EFD23172FCA69C9CC256D2B0073E046
Landscape Assessment Mangere Puhunui Rural Zone Review. Auckland City Council Document. Retrieved from http://www. aucklandcity.govt.nz/council/documents/districtplanmanukau/changes/pc14proposedapp12.pdf
Harris and Ullmanâ&#x20AC;&#x2122;s Multiple Nuclei Model. Retrieved from http://angelicaavila.weebly.com/multiple-nuclei-model.html
Urban Planning Theories and Models. Geofrey Yator. Retrieved from http://www.slideshare.net/bgeffa/urban-models-23134278
IMAGERY: Puhinui Reserve. Auckland Design Manual. Retrieved from http://www.aucklanddesignmanual.co.nz/design-for-places/parks/ typologies/ecological/case-studies/puhinui-reserve
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Annual Population Growth Rates Diagram. Statistics NZ. Retireved from http://www.stats.govt.nz/browse_for_stats/people_ and_communi ties/Geographic-areas/mapping-trends-in-the-auckland-region/population-growth.aspx
Google Earth Application
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