Urban waterfront development
The extent of the coastal environment includes many city centre waterfronts. There are eleven cities in New Zealand which have central business districts directly connected with the coast. Their combined number of residents is nearly 2.4 million or 53 per cent of the country’s total population. 3225 Nine of these cities retain connections to traditional port activities (Auckland, Tauranga, Napier, Wellington, Nelson, Dunedin, Invercargill, New Plymouth and Whangarei) and two (Lower Hutt and Porirua) emerged as satellite cities with an added advantage of being close to the coast.
Like rural and smaller coastal settlements, city centre waterfronts are also at risk of coastal hazards and the degradation of coastal and terrestrial ecosystems. Inappropriately designed and built facilities and infrastructure on the waterfront can adversely modify the natural character, landscape, visual or amenity values and cultural and historic heritage of the coast.
New Zealand cities are following many international examples of change in urban waterfronts. As port facilities modernise, expand and move further away from the city centre or reduce their footprint, many urban waterfronts have become multifunctional mixed-use developments. These provide opportunities for new residential areas and economic activities, conservation of history, restoration of natural character, and increased opportunities for recreation and public access.
The vision for urban waterfront development provided by the NZCPS 2010 seeks to ensure that these areas are developed and managed in an integrated and sustainable manner. Several other objectives within the NZCPS 2010 are also relevant in relation to management of water quality, provision of public access, protection of natural and cultural values and management of risks from coastal hazards.
Objective 6: To enable people and communities to provide for their social, economic, and cultural wellbeing and their health and safety, through subdivision, use, and development, recognising that:
- the protection of the values of the coastal environment does not preclude use and development in appropriate places and forms, and within appropriate limits;
- some uses and developments which depend upon the use of natural and physical resources in the coastal environment are important to the social, economic and cultural wellbeing of people and communities;
- functionally some uses and developments can only be located on the coast or in the coastal
- marine area; …
The direction provided by the NZCPS 2010 is particularly useful when addressing a number of conflicting challenges facing urban waterfront development in New Zealand:
- Established local and national infrastructure, such as ports, railways, roads and submarine cables, need to operate without interruption to help connect city centres with local and international networks
- The natural and physical resources important to tangata whenua, including kaitiaki, and to the economic and social wellbeing of cities, need to be preserved and maintained including coastal water quality, natural character, landscape and amenity values
- The recreational and remaining natural attributes of the urban coastline, and attraction of the waterfront as a place to live and visit, need to be preserved, while controlling the growing pressure placed by the increasing number of people on coastal space and other resources
- Inland activities need to be controlled to mitigate their adverse impact on coastal water quality
- The adverse effects of natural hazards on activities and properties along the urban coastline need to be managed
Waterfront cities traditionally operated as seaport towns, which traded resources harvested from the coast, and processed and stored goods in adjacent, purpose-built industrial facilities. More recently, councils and developers have been engaging in the revitalisation of derelict industrial land and, in some cases disused portions of the port, to introduce mixed-use development that will help drive economic growth and reinvent their cities. These activities can significantly alter the nature and functioning of the coastal environment as di d the former industrial activities.
Research shows that the worldwide trend of regenerating waterfronts can increasingly damage the coastal environment. 3226 This is demonstrated by the decline in water quality and fish populations in many harbours, and the progressive alteration of key coastal habitats. The issues often associated with urban waterfront development include:
- Potential loss of natural and historic character and features due to inappropriate development
- Loss or damage to property due to coastal hazards such as sea level rise, inundation, subsidence, slippage and erosion (with or without a seawall), storm surge, and tsunami
- Pollution from contamination of historic industrial land, dredging and point and diffuse sources of stormwater and wastewater discharges
- Socio-economic conflict in the allocation of public and commercial access to the water
- Loss or decline of aquatic habitats and overall coastal ecosystems due to poor and declining water quality created by pollution and sedimentation
- Decrease in the quality of urban coastal edges due to inappropriate development
- Inadequate provision of public access
- Demand for reclamation and structures extending into the coastal marine area
- Lack of integration between planning for management of the land and the marine area
- Achieving an appropriate mix of activities to make redevelopment economically viable while ensuring vitality of public spaces
- The appropriate provision of different types of public open space adjacent to the water
- The need to upgrade or improve expensive infrastructure in order to enable new development, such as stormwater and services
- Addressing iwi values and interests
On the positive side, regeneration projects can aid in significantly cleaning up former industrial damage, resulting in pollution reduction and ecosystem restoration. Many waterfront agencies seek environmental accreditation to assist in achieving a sustainable waterfront and reducing negative impacts on the wider coastal environment.
The NZCPS 2010 does not distinguish between policies which apply to rural or urban settlements. Due to this, many of the policies apply to new and existing urban waterfront developments.
The NZCPS 2010 directs local authorities to adopt both a precautionary and integrated approach to managing the coastal environment. The integrated approach requires coordinated management of the coastal environment across different administrative boundaries, applicable laws and activities (Policies 4, 5 and 6). This is particularly relevant for waterfronts because they are places where:
- The conflict between conservation and development is more intense
- Equally important public, commercial and infrastructure provision compete for limited space
- Development makes physical changes to the natural environment
- The cumulative effects of urban activities affect water quality and marine ecosystems
Policy 7 requires local authorities to be strategic whilst adopting a precautionary and integrated approach. It is important that a waterfront development plan shows where, how and when future development will take place. It will also need to indicate what activities will be appropriate or not, and how the development can manage the risks of adverse cumulative effects, coastal hazards and reaching the capacity threshold of the coastal environment.
Protecting urban waterfront development
The NZCPS 2010 focuses on hazard adaptation, avoidance and risk mitigation over a 100-year timeframe, with preference for the use of soft and natural protection (Policies 24 to 27). Hard protection structures are only to be used to protect infrastructure of regional or national importance.
City centre waterfronts, being regionally important, typically use hard protection structures due to the pressure on available space, the value of infrastructure located directly adjacent to the coast, and the already modified nature of the environment.
Maintaining water quality
The NZCPS 2010 seeks to maintain high water quality, even in an urban coastal environment, to the point of restricting existing uses to give priority to improving water quality (Policies 8 and 21). This is to support aquaculture (where approved and operational), land-based but water-dependent facilities (such as fishing platforms), marine ecosystems, natural habitats and water-based recreational activities (such as swimming). Policy 22 requires that development should not create significant sedimentation in the coastal area and there should be controls on land use activities to help reduce sediment loadings in runoff and stormwater systems. Policy 23 requires operators of port and marine facilities to take all practicable steps to safely contain and dispose of sewage, wastes and other contaminants from vessels.
Fostering economic activities
While focused on maintaining the natural state of the environment, the NZCPS 2010 seeks to ensure that urban waterfront development does not adversely affect the ability of the country’s national and international ports to operate and connect efficiently and safely with other ports and land-based transport modes, and to develop in a strategic manner (Policy 9). Policy 10 generally discourages reclamation, unless this results in regional benefits. Where this is considered suitable, the design and form of the reclamation should have regard to the effects of climate change and sea-level rise and avoid the use of contaminated materials. De-reclamation of redundant land is encouraged only where it would help restore the natural character and provide for more public space.
Protecting the natural environment and character
The provision for the protection of the natural and historic environment, character, features and landscapes of the coastal environment is a key direction in the NZCPS 20101 and is of particular relevance to urban waterfronts. There is a requirement for activities to avoid significant adverse effects and to avoid, remedy or mitigate adverse effects on indigenous biodiversity (Policy 11) and a restriction on discharges to the coastal environment of harmful aquatic organisms created by urban development (Policy 12).
There are also a number of policy provisions which promote the protection of the natural and cultural environment. These protect remaining natural character, landscape values and historic heritage. They also promote the restoration of natural character, indigenous habitats and ecosystems and sensitive redevelopment of waterfronts can help achieve this.
Providing public access
The NZCPS 2010 seeks to ensure that the public will have sufficient access to the coast and this is particularly relevant to urban waterfronts where there is a strong expectation of public access. Policy 18 directs councils to provide public open spaces for both active and passive recreation, ensuring that their location and treatment contribute to the natural character, features, landscapes and amenity values of the coast. It also requires consideration of future requirements, taking into account the likely impacts of natural coastal processes and climate change. Policy 19 seeks to maintain and enhance public walking access to and along the coast that is practical, free of charge, and safe, with restriction where necessary to protect certain species, historic heritage, public safety and temporary activities.
Approaches to management
While the management approach for rural and provincial urban waterfront environments tends to focus on natural preservation and soft protection, a different approach has been applied to city centre waterfronts. Here the focus has been more on character preservation, sustainable development and hard protection. This has allowed for continued redevelopment, to maximise the use of finite waterfront resources within the urban area, and to provide for regionally and nationally significant activities. There are a number of different management approaches that can be adopted in addressing urban waterfront development, with some of the key ones outlined below.
Integrated coastal management
By taking into account the goals, needs and characteristics of the waterfront itself, the wider coastal environment, and the city as a whole, integrated management can lead to optimum decisions on the uses suitable for the waterfront and the connections between them. This approach supports sustainable development where waterfront regeneration can generally result in social, economic and environmental benefits. This, however, requires an effective regulatory framework, political will and crosssector cooperation, to facilitate long term planning. 3227 The key to successful integrated management is effective waterfront organisation, in spatial and administrative terms. Spatial organisation involves clustering uses according to their relevance to sustainable development and location. Although waterfronts promote mixed use and diversity, there should be a distinct definition of the various activities involved.
Administrative organisation may involve the creation of an agency under the council to ensure that development is administered in a sustainable and strategic manner, and is integrated into the management of the wider coastal environment. Such an agency should consider the waterfront as a top rank spatial system conforming to the wider ecosystem. The agency can provide a lead for integrated management of the coastal area. This will allow coastal area management and waterfront planning to usefully interact in order to generate long term positive feedback in determining the role of the waterfront, reaching agreement on overall management goals, and resolving the triangular city-port-industry issue of locational, organisational, environmental and aesthetic incompatibilities. 3228
Smart growth is a strategic public sector solution to sprawl, which aims to intensify areas where investment in services and infrastructure can be maximised, and which are outside of environmentally protected areas such as the coast. Waterfronts have been the target for intensification in recent years due to their proximity to the city centre, the considerable benefits obtainable from regeneration, and the high value of the land. Smart growth approaches are therefore applicable to waterfront redevelopment.
Smart planning ensures both non-water and water dependent uses are cohesively in balance so that the waterfront can better adapt to fluctuations in the economy, weather or seasonal changes. 3229 There are ten identified elements of a smart coastal and waterfront development which are: 3230
- Mixed land uses
- Compact design
- A range of housing choices
- Walkable communities
- Distinctive, attractive communities
- Open space and critical environmental areas
- Development directed toward existing communities
- A variety of transportation options
- Predictable, fair and cost-effective decisions on development
- Community and stakeholder collaboration
The new urbanist approach seeks to protect the design, form and character of the coastal environment, using private sector initiatives to design and create the aesthetics of specific sites on the waterfront. Although it promotes a compact built form and the human scale, new urbanism is not concerned with regional growth management or land economics goals of smart growth. New urbanism allows for both water and non-water uses while protecting and restoring the natural landscapes and ecological systems of the waterfront. There are well documented principles of the new urbanism movement which are:
- Mixed use and diversity
- Mixed housing
- Quality architecture and urban design
- Traditional neighbourhood structure
- Increased density
- Smart transportation
- Quality of life
Placemaking is a growing movement with no set definition and it is still open to various interpretations. 3232 It is concerned with the creation, management and programming of spaces to increase their accessibility and ability to facilitate social interaction or economic exchanges between friends, cultures and land uses, both day and night. As such, it is a central concept of all urban regeneration projects, including those on the waterfront.
Urban ecology and landscape urbanism
Urban ecology and landscape urbanism adopt a systems approach in order to understand how human and ecological processes can coexist in the urban coastal environment. The approaches suggest that the waterfront should serve both people and nature, integrating humans and non-humans in a functional and just ecosystem.
Mixed-use development is perceived as a way to plan for growth, in a manner that both protects the environment and strengthens the economy, by providing a balance between competing demands. With a clearer understanding of the relationships between land, water and humans, as well as changing development conditions created by population growth, demographic changes and declining natural resources, policymakers can effectively determine the good and bad effects of mixed-use development on the value and use of waterfront land.
The renewable energy resources (such as solar, wave and wind) and walking and cycling opportunities on the coast can help reduce dependence of the waterfront on fossil fuels. Treating stormwater runoff, before discharging it to the sea, can help restore the aquatic habitat and provide the public with safer contact recreation with the water.
Progressive risk reduction
Progressive development and risk reduction is an incremental approach to address the ever-changing shifts in the landscape of the urban waterfront. It allows for progressive improvements, with risk reduction set as a long term goal. It requires new developments to progressively adapt to changing social and economic conditions while avoiding being exposed to risks. This effectively helps reduce the level of coastal hazard risks over the intended serviceable lifetime of the waterfront. Progressively, the level of risk to existing development is reduced over time. 3233
Best practice planning elements
Regional and district plans can incorporate the following elements in order to address the environmental issues surrounding urban coastal development:
(1) Map out natural and historic aspects to be protected
Giving special planning attention to important aspects of the natural and historic character of the waterfront can help protect ecological, amenity and cultural values. It can also protect traditional water-dependent activities and offer opportunities to provide a sense of place and continued access for future generations.
- Priority is given to protecting natural and historic areas, character, the overall “look and feel”, and view shafts that are socially, ecologically and economically significant and at risk of being affected
- Viability of retaining natural and historic elements is investigated in the context of the social, environmental, economic and cultural outcomes sought
- Protected natural and historic character is reflected in new developments through the use of public art, structures, activities and materials that connect the old with the new and promote diversity.
Desirable example: The Auckland Waterfront Heritage Study 2011
Salmond Reed Architects Limited identified and mapped out Māori, colonial and natural heritage features, as well as ecological, geological and archaeological sites on the waterfront, to help protect and celebrate heritage in the future through the waterfront planning process.
(2) Promote community involvement
Promoting and sustaining stakeholder engagement and collaboration throughout the planning process can help to establish community buy in to waterfront redevelopment. It assists with determining the underlying issues and impacts and in resolving the allocation, function and connection between land and water uses. It also assists with gaining agreement on the identity and role of the waterfront within the city. Successful public engagement facilitates effective administration of the development process and helps to avoid adverse reactions to it.
- Focus regular and steady involvement on limited yet attainable goals in the beginning, while gradually making results visible
- Strongly support the development of public-private partnerships to assist with land use integration and implementation
- Emphasise the restoration of water and coastal quality, and provide openness and accessibility to the public, acknowledging that the coast is an important resource of the city
- Ensure that development decisions are predictable, fair, cost-effective and implemented through consistent policies and coordinated permitting processes
- Involve stakeholders in mapping and developing risk responses to determine their level of exposure to risk, their social or economic vulnerability to it, or concerns about the planning process
- Employ good public relations and communications that can reach a wide cross-section of the community
Desirable example: San Francisco Waterfront, USA
The Port of San Francisco engaged an independent party to resolve conflicts between users on noise, traffic and parking issues. This provided stakeholders with a sense of justice, impartiality and transparency, which resulted in a plan that successfully describes acceptable and unacceptable land uses, and opportunities for mixed uses.
(3) Use strategic planning to provide the basis for resource allocation
Applying strategic planning to urban coastal development can result in a coherent and pragmatic plan that clarifies the relationship between uses, applies an ecological approach which addresses the needs of both the coastal environment and urban development, and creates a general consensus in defining the sustainability outcomes for the waterfront.
- Direct infrastructure and activities towards benefiting existing and proposed communities
- Focus planning on increasing efficiency in the use of finite land and resources, minimising adverse visual and physical impacts on the coastal environment, and balancing the interface between public and private use
- Ensure a clear distinction between areas where protection is encouraged and areas where change is acceptable
Desirable example: Wynyard Quarter Plan Changes, Auckland
Formal statutory plan changes for Wynyard Quarter (Plan Change 4 of the Auckland City District Plan and Plan Change 3 of the Regional Plan Coastal) followed and complemented a comprehensive process of strategic planning. This included the preparation of:
- The Auckland Waterfront Vision 2040, Urban Design Framework, Sustainable Development Framework, Transport Plan for Wynyard Quarter and considerable stakeholder participation
- Vision 2040 set out the framework for the desired community outcomes
- The Urban Design Framework provides the design principles that will help integrate the site into its unique coastal setting
- The Sustainable Development Framework establishes targets based on meeting a quadruple bottom-line
- The Transport Plan constrains the supply of parking and road space
In combination they all help to ensure a balanced allocation of land uses in Wynyard Quarter.
(4) Set appropriate zoning and activity classification
Setting site-specific rules for building, materials, zoning and activities can assist with:
- Visioning by distinguishing and defining the interface between the acceptable and prohibited, public and private, built and open, passive and active, urban and coastal, and temporary and permanent
- Resolving conflicts in use and form
- Managing the balance between cultural, social, commercial and environmental needs
- Protecting the maritime setting
- Mixed use is given permitted activity status to increase pedestrian access to the water, made controlled to establish and maintain cohesive waterfront activities, or made discretionary or non-complying in some areas to minimise adverse environmental impacts
- Water-dependent public, cultural and economic activities are given priority over the use of the coastline, but controlled to address cumulative effects and reverse sensitivity issues
- Existing natural character, historic heritage and view corridors to the water are protected
Desirable example: Auckland Council City district Plan Operative Auckland City – Central Area Section 2005
Part 14.9 uses activity classification, integrated planning, assessment criteria, development controls and financial contributions to address the issues onsite and in the wider social, economic and environmental context. This is in order to protect maritime use, to allow for mixed use, and to promote progressive redevelopment.
(5) Incorporate risk resiliance
Regional and district plans can introduce policies to adapt, protect and increase resilience of existing infrastructure, private property and public accessibility of urban coastal development, against risks of reversible and irreversible effects of contamination, climate change and natural hazards.
- Predictions on risk, insurance and related issues need to be understood and estimated, regularly monitored, mapped, agreed and planned for reduction, readiness, response and recovery
- An independent multidisciplinary review process can be adopted to incorporate scientific and technical risk resilience expertise in planning and monitoring new and existing development
- Remaining natural systems and vegetation that provide natural defences should be protected or replaced with equivalent hard infrastructure solutions, with corresponding rules
- Carbon dioxide emissions can be reduced through policies that encourage onsite energy generation, low impact public transport and sustainable building, with expected targets
- Water quality should be regularly monitored for contamination by shipping, industry, development and dredging activities and impacts on aquatic habitats and humans, with expected site-specific targets
- Elevated buildings, where found appropriate, should encourage walkability and be sympathetic to the existing character and form of the coastal environment
- Street and transit systems should be designed to provide options for evacuation during disasters
- Infrastructure should be provided to ensure wastewater overflow does not mix with the stormwater system or contaminated land, and allow for fast drainage
Desirable example: Climate Change Impact Statement, Queensland Government, Australia
The Department of Environment and Heritage Protection requires proponents of any project, policy or legislation seeking state approval to produce a Climate Change Impact Statement. The government prepared a 14-step risk management plan template to assist proponents in preparing such statements.
Best practice design elements
Development designed to promote a sustainable urban waterfront can include the following elements:
(1) Strengthen connections with the water
Reinforcing the connection of the development with the water, visually and physically, can help increase public access and use of the coast and protect activities that heavily rely on the water.
- Parking is located at a distance to encourage walking or cycling to and along the coastline
- Sightlines to the water are enhanced through roads, laneways, linear parks, buildings decreasing in height and public spaces orientated towards the coast
- Water-dependent activities for the public and businesses, and intertidal marine ecosystems, are given priority to use appropriate areas of the coastline
- Public open spaces and features such as tidal steps, lookout points and fishing platforms are provided to encourage public connection with the water and to help retain natural processes in a modified environment
- Existing and authentic water-based activities, such as fishing, marine activities and public transport, are integrated into the design and this helps to provide interest and vitality and to reinforce connections to the water.
Desirable example: Waterfront Walkway and Cycleway, Auckland
The project will create six kilometres of continuous walkway and cycleway across the waterfront, to encourage walking and cycling, increase access to the coastline, provide sightlines to the water (for example Daldy Linear Park) while protecting, where appropriate, the commercial use of the water’s edge.
(2) Soften the coastline
By retaining and enhancing green spaces and natural features along the water’s edge, waterfronts can help enhance the marine ecosystem, improve water quality and amenity, provide new recreational and lifestyle opportunities, and increase resilience against the risks of coastal hazards.
- Natural vegetation and beaches are retained where possible
- Foreshore areas are revegetated with native planting where practicable
- Public parks and open spaces are mostly located along the coastal edge
Desirable example: Elliott Bay Seawall, Seattle, USA
The seawall is being built not only to reduce the risks of coastal storm and seismic damage, but also to restore the ecosystem through substrate enhancement, provision of riparian vegetation, and building light-penetrating sidewalks that provide lighting to the intertidal bench and textured wall underneath
(3) Adopt low impact design
Incorporating low impact or water-sensitive design in urban coastal development can help reduce the adverse effects of stormwater runoff and drainage on the environment, enhance ecological values and increase the visual and recreational amenity of the coast.
- Low impact design devices are integrated where possible across the waterfront
- Only treatment and storage (rather than infiltration) of stormwater are to be used in contaminated brownfield sites
- Runoff from new development is minimised by building curbless, gutterless and narrower streets, and using green roofs, green walls, swales, rain gardens (bio-retention cells), tree box filters and innovative materials like porous concrete, permeable pavers or recycled site furnishings
- Low impact design techniques are integrated within streets and open spaces so natural processes and associated vegetation can be seen and understood
Desirable example: Waitangi Park Wetland, Wellington Waterfront
The 6.5 hectare recreated wetland significantly increases the quality of urban stormwater by subjecting it to daylight, natural and engineered filtration systems and storage before it is discharged into the harbour or re-used for irrigation.
(4) Promote mixed use and diversity
By maintaining an optimum level of diversity, in both use and form, the waterfront will be walkable, compact and more attractive to people of different ages, incomes and cultures. It will also help promote social and economic exchanges, provide vitality to public spaces at different times of the day, and increase the viability of businesses locating on the waterfront.
- A balanced mix of shops, offices, industries, activities, events and housing is maintained and orientated towards the coast
- Density is kept to a level sufficient to make the place vibrant and safe at night and day
- Water-dependent activities are protected from reverse sensitivity issues created by mixed uses
- A diversity of public open spaces are provided which support physical activity, place making and local communities
Desirable example: Wynyard Quarter, Auckland Waterfront
Wynyard Quarter is expected to accommodate between 2,500 and 4,000 residents and between 12,000 and 15,000 workers in a diverse environment with public, retail, office, entertainment, fishing, marine industrial and residential uses, all set in a 37-hectare area of waterfront land and within a three-kilometre long coastal frontage.
(5) Recreate the natural and historic character
Promoting design, function and activities that reflect the history and context of the coast can help protect the environment from drastic changes to the natural landscape, historic heritage and habitat. It can also help to develop a strong sense of place that makes a waterfront distinctive and attractive.
- Quality restoration and adaptive reuse of heritage buildings, marine structures (such as North Wharf at Wynyard) and spaces by the water’s edge are encouraged
- Development is designed to minimise visual and physical impact on the natural and historic character
- Historic landscape character is revealed through innovations in the use of materials, public art, activities, events, native planting, place names, vistas, signage and urban form
- Opportunities for new types of open spaces and publically accessible water edge conditions are embraced
Desirable example: Jellicoe Precinct, Auckland Waterfront
The 3.7 hectare precinct embraces the historical and gritty experiences of a working waterfront through the adaptive reuse of structures such as warehouses, slipways, silos and shipping containers; the retention of artefacts like rail tracks, bollards and salvaged seawall stone; and the use of structures, public art, planting, play equipment and events that depict the history, culture and nature of the coastal environment.
Buhociu D H, 2013, ‘Contemporary environment challenges in waterfront development’, Urbanism. Arhitectura. Constructii, 4, 39-42
Papatheochari D, 2011, Examination of best practices for waterfront regeneration, conference paper presented at the Littoral 2010 – Adapting to Global Change at the Coast: Leadership, Innovation, and Investment, available at http://coastnet-littoral2010.edpsciences.org/articles/litt/pdf/2011/01/litt-02003.pdf
Vallega A, 2001, ‘Urban waterfront facing integrated coastal management’, Ocean & Coastal Management, 44, 379-410
Quinn K J, 2012, Sustainable urban waterfront: Re-imagining waterfronts as inclusive public spaces, Master’s thesis, Graduate College, The University of Arizona, Tucson
National Oceanic and Atmospheric Administration, 2011, Achieving hazard resilient coastal and waterfront smart growth, coastal and waterfront smart growth and hazard mitigation roundtable report, National Oceanic and Atmospheric Administration, Washington DC
Ministry for the Environment, 2008, Coastal hazards and climate change. A guidance manual for local government in New Zealand, 2nd edition, Revised by D Ramsay and R Bell (NIWA), Ministry for the Environment, Wellington
Last updated at 2:12PM on February 25, 2015