What Shape Will Christchurch Become?
TL: DR
1. For most possible futures Christchurch’s proposed draft spatial strategy has insufficient housing developmental capacity.
2. There is an ‘all the eggs in the one basket’ risk that the positive benefits of the proposed mass rapid transit (MRT) growth corridor will not be actualised because insufficient transit is being planned for.
3. This outcome can be avoided. Win-win outcomes that are both good for affordability and the environment are possible if preparatory planning and infrastructure investment are made for secondary growth corridors that use new transit-oriented development (TOD) tools, institutions, and policies.
Discussing The Draft Greater Christchurch Spatial Strategy
The Greater Christchurch partnership has released its draft spatial strategy alongside of the Greater Christchurch Public Transport Futures Mass Rapid Transit Indicative Business Case. The draft spatial strategy relies heavily on the mass rapid transit (MRT) plan. To understand the rationale of the draft spatial strategy you need to have an overview understanding of both documents. These are hugely important pieces of work because they will determine the shape of Greater Christchurch going forward. Unfortunately, the draft spatial strategy has received little public discussion.
Mass Rapid Transit to Shape Greater Christchurch
Overall, I am supportive of the transport aspects of MRT plan, as it will be a much-needed multi-modal improvement to Greater Christchurch’s transport network that will deliver many benefits. I have some quibbles about the route — but my major concern from the two reports is the draft spatial strategy.
Before I discuss my concerns, it is worthwhile detailing the benefits of the transport and spatial planning proposals.
The MRT transport proposal is a genuine mass rapid system. It has been carefully designed to a familiar international standard (Sydney, Brisbane, Edinburgh, and other European light rail projects etc). The MRT business case is the culmination of a large body of work that tackles worthy causes, such as, addressing climate change, providing a solution to the build-up of motor vehicle congestion, and combating negative externalities that result from Greater Christchurch’s excessive car dependency (Canterbury has a higher per capita car ownership rate than even the US).
When the MRT system is built it will unlock the infrastructure and upzoning for 50,000 additional housing units. Thus, MRT will significantly increase the development capacity of Christchurch. Increased development capacity means more housing choice, more competition, and more affordable housing. This is a very good thing that underpins many initiatives — from attracting students to study at the region’s tertiary institutions, to improving the work/life balance for industries with worker shortages, and many more initiatives of an economic, inequality, or environmental nature. From a spatial planning perspective this does though raise the question:
If a mass rapid transit corridor is to shape Christchurch’s future growth is the planned 22km long growth corridor enough?
The Christchurch Press has written an article titled Mass rapid transit and high-density housing — how Greater Christchurch can cope with 1 million residents. I question the validity of the claim that higher density housing within the proposed MRT corridor would be able to cope with Christchurch growing to 1 million residents.
The expectation that Christchurch can cope with growing to 1 million residents is because the main map in the draft spatial strategy explicitly states the proposed city design would have a capacity for 1 million people. Map 2 is titled “The Greater Christchurch spatial strategy (1 million people)”.
This map visually represents what the document describes as the “opportunities, directions and key moves” that make up the draft spatial strategy.
The draft spatial strategy does not detail its workings for how its city design would cope with Christchurch becoming a city of 1 million people. Yet the reports contains multiple directives (see the accompanying image for an example) that indicates it was tasked to do so, as some of the most important ‘directions’ deal with issues like developmental capacity, housing choice, affordability, and delivering thriving neighbourhoods.
Unfortunately, due to the size and detail of Map 2 it does not easily illustrate on this Medium document format, but the main features are easily described.
The key aspect of the proposed strategy is greenfield growth is limited to existing future zoning in a few outlying towns — such as Rolleston, Lincoln, Prebbleton, Kaiapoi, and Rangiora. Each in effect has a greenbelt — as does Christchurch as a whole.
These ‘greenbelts’ exist both explicitly because on the planning map there is very little area zoned for future residential or industrial development and implicitly because there is no planned additional greenfield infrastructure. This includes no public-right-of-ways being set aside — for example no land is allocated for future trunk utility services, there is no designation of paper arterial roads, paper rail lines (for freight or MRT), or land set aside for future greenfield transit-oriented developments.
This is not an oversight, it is the intention of the spatial plan — the strategy explicitly explains it intends to limit greenfield expansion, so there are no plans for any new or upgraded infrastructure corridors outside of Greater Christchurch’s existing urban footprint.
Within the existing urban footprint, the draft spatial strategy is for one growth corridor that will be delivered in two stages. This being the 22 km mass rapid transit line that initially goes between Church Corner in Riccarton, the city centre, and Papanui at stage one. The second stage is an extension at both ends to Hornby and Belfast.
It is helpful to look at Christchurch’s and Canterbury’s past growth patterns to gain a ballpark sense of the possible future population growth scenarios — check out this short paper (3min read) here.
Historically policy makers have both under and over estimated population change. What is needed is a spatial strategy that is adaptable enough to cope with multiple change scenarios — including that Christchurch becomes a city with a population that exceeds 1 million. If the metropolitan area continues its current growth trajectory it will exceed 750,000 people in less than 30 years and be well over a million in 60 years time.
In recent decades, greenfield house construction has made up approximately 50% of Greater Christchurch residential building response while infill housing has made the other 50%. Going forward, the proposed strategy is for construction in the urban area around the mass rapid transit (MRT) line to replace greenfield construction. This one relatively short in length MRT line will be the only urban growth corridor for Christchurch. In the wider metropolitan region, it is the only location where infrastructure is planned to be upgraded and zoning is to be more permissive.
The spatial strategy details an estimated additional housing response that the MRT line will enable, based on the amount of housing per hectare such transit schemes have enabled elsewhere. I have collated these numbers on the chart below. Note my estimates for the localised increases in population is based on each housing unit having on average 2.5 occupants (which is the regional average).
A spatial plan for Greater Christchurch doubling to a population of 1 million people needs to make room for an additional 200,000 housing units (assuming 2.5 people per household).
The proposed 22km long MRT corridor from Hornby to City to Belfast is estimated to provide only 25% of that needed housing capacity — it could provide 50,000 houses out of the required 200,000 houses.
Canterbury for several decades now has been the New Zealand region with the second largest house building market. In the last five years Greater Christchurch (Christchurch, Selwyn, Waimakariri Councils) has issued building consents to between 4,234 (2018) and 7,589 (2022) residential housing units on an annual basis. At these building rates Greater Christchurch could construct between 127,000 and 228,000 houses over the next 30 years.
Given the draft spatial strategy assumes that going forward half of all residential construction will be in the MRT growth corridor. This means we can determine how many years of growth at the 2018 to 2023 building rates is being catered for. Annually, this would require between 2,117 and 3795 houses to be constructed within the corridor. Meaning, the growth corridor will provide space for residential construction for between 13 to 24 years before its capacity limit is reached. In terms of future generations — only one generation is being planned for.
There is a strong possibility that this limited capacity will not be achieved though. Because by restricting development to such a degree this will be a signal to land bankers to hoard the building opportunity. Property owners within the growth corridor instead of seeing an opportunity to build may consider they hold a special no-lose lottery ticket whereby they need do nothing to achieve ever larger land value increases. If this scenario does play out it will unnecessarily further restrict construction supply and it will unnecessarily inflate the cost-of-living in Christchurch.
Only having one short growth corridor may also affect local politics — empowering local political entities, such as, resident associations. They may seek to protect the ‘status quo’ of the light rail suburban gentrification process. These residents associations might campaign to limit change in the built environment while privately being pleased about the amenity that light rail provides. If this sort of campaigning is successful then the main change in the light rail suburbs will be rapidly escalating house and land values i.e. the $4bn public investment in light rail will be capitalised into higher private property prices. The cost of light rail will be incurred by all rate and tax payers while the main benefits will be privatised to a relatively few property owners. See the paper New Zealand’s Addiction to Land Speculation is its Forever Weakness for further discussion of the land speculation issue.
A short walk around Christchurch’s city centre quickly exposes that the city has a problem with land banking. Despite $billions of public investment in city centre anchor projects in the past twelve years since the 2010/11 earthquakes there remains numerous unbuilt gaps in the built environment.
Land values will always rise in response to improvement in amenity. This is not problematic if there is no restriction on constructing a higher density built environment. Because the cost is spread across a greater number of households and businesses. But if development capacity is limited, especially if there is no competitive tension from alternative development options, this allows property owners to extract an additional speculative value from their land holdings. This will add to affordability and gentrification problems, which is one of the concerns I have about the draft spatial strategy. Yet even if the draft spatial strategy is successful it is likely to quickly run out of capacity.
Even with the assumption that the draft spatial strategy house building numbers can be achieved — which is doubtful because of the land banking problem.
The Greater Christchurch draft spatial strategy provides a developmental capacity of only a 50% increase in population to 750,000, not a 100% increase to 1 million people the draft spatial strategy initially appears to provide.
What are the implications of a reduced developmental capacity?
If demand for new housing in Greater Christchurch decreases, then the reduced developmental capacity of the draft spatial strategy will not be problematic. Some cities around the world, such as Detroit and in the New Zealand context Invercargill, have affordable housing because supply responsiveness is not a factor due to there being little demand. Going forward it is possible this scenario could play out for Christchurch, too.
Alternatively, demand for housing construction could remain high and given the plan is to restrict development capacity then land and house prices will rise higher than would otherwise have been the case. Specifically, this means in the walkable catchment areas of the MRT growth corridor, such as Riccarton, Merivale, and Papanui, will become very gentrified. This will exclude middle- to lower-income households from taking advantage of the amenities provided.
In short, the negative consequences of the cost-of-living and housing crisis that New Zealand is now familiar with will be exacerbated by Greater Christchurch’s proposed reduced developmental capacity.
Restricted housing supply capacity and steeper house price rises is a particular problem for English-speaking countries. It is likely this is affecting the Anglo-world making them feel poorer and less confident.
Christchurch in the past five years has built at a fast rate because it is one of the few places in New Zealand where housing can affordably be built at scale. Yet the draft spatial strategy risks Christchurch losing that role. This would not only be bad for Christchurch it would be bad for New Zealand.
What was remarkable about the 2010/11 earthquakes, was after the initial shortage period, homes became relatively more affordable. An economic report* investigating the housing lessons from the rebuild found that unlike other parts of New Zealand, house prices did not rise relative to incomes despite rapid population growth. This is striking since Canterbury lost over 28,000 homes due to the quakes.
What was particularly successful was land supply across the wider regional labour market area via rezoning was fast tracked providing abundant development capacity meaning new and relocating households could take advantage of motorway transport amenity which was also delivered rapidly. In summary — after an initial shortage period, housing supply became more competitive in the face of rising demand.
The new draft spatial strategy can be seen as an attempt to correct the excessive car dependency of the previous Urban Development Strategy (UDS). To be successful it must learn from both the successes and failures of the previous UDS strategy. In particular it must ensure it has sufficient development capacity so that competitive tension provides housing choice and affordability.
Going forward only a decade or two if Christchurch implements the draft spatial strategy, it risks finding itself in an awful trade-off position of having to choose between two bad options — degrade the environment or inflate the cost-of-living crisis further. The pressure to restart car dependent sprawl will be immense despite the known consequences for energy use, CO2 emissions, traffic congestion, long-run infrastructure costs etc. Yet, a better spatial plan that could avoid this trade-off and have good outcomes for both the environment and affordability would be achievable if the draft spatial strategy is improved upon with preparation for more transit oriented developmental capacity that can come on-stream if required.
To understand how to improve the draft spatial strategy it is helpful to review how overseas cities have simultaneously achieved good environmental and affordability outcomes.
The MRT business case quite rightly points out the benefits that overseas cities have achieved from having higher urban density — in particular lower per capita transport energy use.
The assumption of the Greater Christchurch planning documents seems to be that overseas cities achieved their higher densities by stopping outward expansion forcing these cities to grow up. There are a group of New Zealand planners and people in the wider public who believe this approach is self-evident, common sense even. They believe that allowing any outward expansion will reduce density. Implicitly they believe that cities respond best to the ‘stick’. Yet successful overseas cities that have higher urban density and lower per capita transport emissions than New Zealand cities were not the product of this ‘stick’ approach. They have well established planning policies that enable both up and out urban development.
The evidential basis that restricting outward expansion of urban areas is how overseas cities have achieved higher urban density and lower per capita transport energy use is actually weak. This issue is fully explored in my paper — Great Cities have Great Networks.
Copenhagen is a good example of a city that has a long-term spatial strategy that embraces both up (densifying the palm) and out (urban expansion along the fingers with transit-oriented development). Copenhagen by following this strategy was able to cope with its post WW2 expanding population and increased rate of housing construction without experiencing a cost-of-living crisis or degrading its environment with high per capita energy use, CO2 emissions, excessive traffic congestion etc.
It is notable that Copenhagen’s transit length is eight times what is being proposed for Christchurch. Copenhagen when it initiated its finger plan in 1947 is about the size of what Greater Christchurch is now. This supports the contention that Christchurch could develop a significant infrastructure deficit in its proposed primary growth corridor. This is especially problematic because the draft spatial strategy is that half of all new housing will be within the walkable catchment of the mass rapid transit corridor. Meaning, a transit infrastructure deficit would translate to a housing deficit.
The New Zealand Infrastructure Commission has thought deeply about the capacity constraints of infrastructure. Many of the considerations in this discussion document are based on their work. I would greatly encourage anyone considering New Zealand’s infrastructure needs utilise the Commission to aide their thinking — especially the authors of the Greater Christchurch draft spatial strategy.
To get a feel for the Commission’s thinking — listen to this podcast of Bernard Hickey interviewing Geoff Cooper the head of strategy at the Commission about equity and ensuring a fairer infrastructure cost for all. In particular they discuss the following in some detail.
- The difference between the user pays and beneficiary pays principles, especially land owners benefiting from infrastructure provision.
- High land prices being an infrastructure cost and how the differential between rural and urban prices is widening for most New Zealand urban areas.
- The problems with ‘just-in-time’ land acquisition for infrastructure provision (which is what New Zealand does).
- Uncertainty adversely affecting infrastructure provision due to unexpected population change, increasingly volatile weather events, unexpected land price increases etc.
- Avoiding trade-offs between infrastructure considerations and the environment considerations — that it is possible to achieve wins for both.
- And finally, the need to bring New Zealand as a collective along on this infrastructure fairness journey because with climate change commitments, electrification of the economy etc we need to be nimble and fast in our decision making to meet these challenges.
What would a good spatial strategy for Christchurch look like?
The Christchurch MRT transport project is a good development for the city and region. I am broadly in support of this project (despite a few concerns regarding the routing of stage 2). A large amount of work over several years has gone into its design. The MRT project capital cost at $4bn is less expensive than the LGWM proposal for Wellington or Auckland light rail because no tunnelling is required.
There is the possibility for New Zealand’s three largest cities to build three similar transport projects that are largely or wholly street running light rail or bus rapid transit schemes (i.e., on the surface rather than underground) if the Auckland largely underground project was converted to a largely surface running transit system as initially envisioned (and this is the option the Auckland Major prefers).
These three schemes could be built in the same investment period — almost certainly for less cost than the more expensive largely tunneled Auckland ‘light rail’ project.
There would be the possibility for achieving scale economies (buying the same type of rapid transit vehicles for instance) and achieving cost savings from implementing learnings from one project to the next (for instance the more refined design of Christchurch’s MRT project already seems to have benefited from the work Auckland and Wellington has done on Auckland Light Rail and Let’s Get Wellington Moving).
The Infrastructure Commission has done a lot of work identifying why New Zealand has high infrastructure costs. Part of the problem is lack of capacity building. That New Zealand should ‘learn from doing’. For instance, the Melbourne level crossing removal project has over time improved its cost effectiveness and delivery efficiency. New Zealand would have this opportunity with surface street running light rail.
For Christchurch the benefits of light rail are likely to be higher than for the other two cities because it will be the first MRT project for the city while Auckland and Wellington already have existing MRT systems.
It is quite possible that Christchurch light rail will have both lower costs and higher benefits so even if combining the three city rapid transit projects together does not eventuate then this shouldn’t necessarily prevent Christchurch’s MRT project from starting in its own right.
Public discussions of Christchurch’s MRT project and local council support appears to have gone well.
Given these factors it makes sense that MRT as described in the draft spatial strategy is Christchurch’s primary MRT project and primary urban growth corridor as long as there are supporting secondary transport projects and growth corridors that can flexibly provide additional developmental capacity for the reasons outlined in this discussion paper.
So, is a Secondary Growth Corridors Strategy the Answer?
In short — yes.
Christchurch needs secondary growth corridors (that intersect to make a growth network) to prevent shortages developing as the primary growth corridor reaches capacity constraints — which could be as little as 13 years away.
A secondary growth corridors strategy will require some initial planning attention and some preparatory infrastructure investment but not to the level of the primary MRT transport project and growth corridor.
Christchurch already has a complete motorway network and any more investment in widening roads at pinch points will not reduce city-wide congestion because of an effect called induced demand.
Christchurch therefore needs in its draft spatial strategy preparatory work for additional rapid transit projects to make a more complete congestion free rapid transit network.
Final Thoughts
In a sense this is the third paper of a four-part series.
The first paper outlined the general characteristics of what makes a city great — it is called Great Cities have Great Networks.
The second much shorter paper discusses Possible Future Population Growth Scenarios for Christchurch and Canterbury.
This third paper examines Greater Christchurch’s draft spatial strategy to determine whether the metropolitan area has the capacity to become a great city and found it probably doesn’t — but a few relatively simple additions to the strategy could easily fix this.
The fourth paper which I have yet to start would look at a specific plan to fix the Greater Christchurch spatial strategy so that Christchurch has the capacity to become a great city with great networks. This paper will examine new transit-oriented development (TOD) tools, institutions, and policies.
*Housing lessons from the Canterbury rebuild Report to the Department of the Prime Minister and Cabinet (DPMC), 15 November 2021, Sense Partners
