The following publications are works either authored by our staff or, in some cases, co-authored with people from outside the company.This selection of conference papers and journal articles can be accessed by requesting individual items from our Tonkin + Taylor Ltd Library (library@tonkintaylor.co.nz) or by clicking on the button beside the item. There is no charge for this service. However, please note that our Library follows Library Association (LIANZA) guidelines (link to their guidelines here) and reserves the right not to supply any item if these conditions are not met.

Waitangi Wharf and Port Upgrade – Providing a critical lifeline at the edge of New Zealand

Author

Foster, Mark , Shand, Tom D. & Bakker, Pieter (2017)

Source

Australasian Coasts & Ports Conference, 2017, Cairns

Year

2017

One of our most remote communities, the Chatham Islands, sits 800km off New Zealand’s east coast and is home to 600 people. The islands are serviced by a port which provides a lifeline for the community through the provision of every-day goods and export earnings. The port is at the end of its structural life and significant upgrades are necessary. The Waitangi Wharf Upgrade, a project of some $58 million, involves reclamation, dredging and the construction of a large breakwater. The NZ Dept. of Internal Affairs requested that the Memorial Park Alliance comprising NZTA, HEB, Downer, Tonkin + Taylor and AECOM deliver upgrade works.
The project progressed from concept design, through consenting and detailed design within 12 months; an extremely tight timeframe for a project of this scale and complexity. Extensive community engagement was undertaken throughout the process including requirements at the port and surrounding areas, existing coastal processes and likely effects of the development and options for social and environmental improvements. This built trust and established relationships, very important factors for a project this size impacting on a very small community (i.e. the construction team increased the total island population by 6%).
This paper presents an overview of the project, and the unique challenges and lessons learned by working in such a remote environment, including:
• The relative importance of the project to its community reframed port activities by highlighting the critical importance of port infrastructure We consider that there is a huge, albeit complex, opportunity for the industry to more strongly connect communities to their ports for the benefit of the industry;
• How we must be sensitive to the communities in which we work, and strive to build strong relationships for everyone’s benefit – particularly so with remote projects; and
• That physical model testing can add significant value in fine tuning a design, and providing confidence in the end solution.

25 year journey of UK water industry economic regulation : lessons from the New Zealand context

Author

Reed, Charlotte

Source

Stormwater Conference 2014

Year

2014

This paper sets out some of the benefits and challenges of regulation, drawing on examples from the United Kingdom (UK). It discusses a range of issues relating to regulatory models, including possible economic models and frameworks for ensuring compliance and the protection of the environment and drinking water standards. The issue of privatisation versus regulation is also considered. There has been an ongoing discussion about the possible regulation of the New Zealand water industry over recent years and learning lessons from other countries will be an important part of any future change. The aim of this paper is to provide some practical insights into regulatory options, to inform future discussion and debate.

The effect of sea level rise on liquefaction vulnerability : a case study for consideration of development on coastal plains and reclamations (1)

Author

Quilter, Peter W. , van Ballegooy, Sjoerd & Reinen-Hamill, Richard (2015)

Source

Australasian Coasts & Ports Conference, 2015, Auckland

Year

2015

The 2011-2012 Canterbury Earthquake Sequence (CES) has highlighted the need for greater understanding of liquefaction and its effect on development in coastal plains and reclaimed areas. It has also provided the ability to see how projected Sea Level Rise (SLR) is likely to affect liquefaction vulnerability.
Published research [6] indicates the thickness of surface non-liquefying material or the "crust", as having a profound influence on the likelihood of land and building damage. Soil needs to be  saturated for it to liquefy and full saturation generally occurs in the soils located beneath the  groundwater table. In granular soil deposits (susceptible to liquefaction), the depth to groundwater primarily dictates the non-liquefying crust thickness. The IPCC Fifth Assessment Report [5] indicates global mean sea level rises between 200 mm and 450 mm within the next 50 years are possible and substantially greater rises could be expected within the next 100 years. These SLRs will result in rises in groundwater levels in coastal plains.
This paper reviews liquefaction vulnerability mapping of residential areas in Christchurch, and presents vulnerability maps for different levels of earthquake shaking based on current and revised groundwater levels reflecting SLR of 0.5m and 1.0m. The change in the percentage of the residential building portfolio in eastern Christchurch likely to experience moderate to major liquefaction related damage for the different earthquake shaking has been assessed for each groundwater scenario.
The implications of SLR are commonly considered for inundation, erosion and tsunami risk. Little mention to date has been made regarding the increased level of risk that SLR will have on liquefaction in geological coastal settings similar to those of Christchurch, including recent coastal plains and reclaimed land. Because SLR increases the vulnerability to liquefaction, SLR effects should be taken into account when assessing this hazard.

Safety of existing small dams : a New Zealand perspective

Author

Duder, John N. & Knappstein, Dewi

Source

Asia 2016 : 6th International Conference on Water Resources and Hydropower Development in Asia, Vientiane

Year

2016

Small dams play an important role in New Zealand for irrigation, town water supply, hydropower, industrial use, flood mitigation, and intrinsic value as lakes in parks. This paper shares some of the particular issues that have been highlighted by the authors’ experience with smaller embankment and concrete dams, and infers lessons for design, construction and operation. The importance of regular monitoring and maintenance is emphasized, including the control of seepage and the assurance of adequate spillway capacity. Reference is made to the new Dam Safety Guidelines issued in May 2015 by the New Zealand Society on Large Dams (NZSOLD) which are essentially the industry standard and which are directly relevant to dams down to a few metres in height but with the potential for downstream damage.

Design and construction of a synthetic lining system for seismic enhancement of Stuart Macaskill Lakes, Upper Hutt, New Zealand

Author

Cherrill, Hugh E. , Eldridge, Simonne & Torvelainen, Eric P. (2013)

Source

19th New Zealand Geotechnical Society Symposium, 2013, Queenstown

Year

2013

The Stuart Macaskill Lakes are High Potential Impact Category earth embankment dams,
forming two raw water storage lakes, supplying Wellington, Porirua, Upper Hutt and Lower
Hutt Cities, New Zealand. A Tonkin & Taylor (T&T) feasibility study in 2008, looking at
increasing the storage capacity of the lakes, found that seismic design requirements have
increased significantly since the construction of the lakes. This paper focuses on the design and
construction of a synthetic lining system for the seismic enhancement of the lakes.
Construction of the lakes, owned by Greater Wellington Regional Council (GWRC), began in
1982 and they were commissioned in 1985. The lakes are constructed on terrace gravel deposits
adjacent to the Hutt River and are located within approximately 20 to 50 metres of the
Wellington Fault Deformation Zone. A Maximum Design Earthquake Peak Ground
Acceleration of 1.08g illustrates the high seismic hazard.
When complete, the new lining system, made of linear low density polyethylene (LLDPE), will
cover an area of approximately 14.5ha. Sliding of cover materials over the LLDPE liner and
spanning of cracks were primary considerations in the design of the liner. LLDPE was
specifically selected over other lining materials for its strength, ductility and frictional
properties.
Of particular interest is the laboratory testing undertaken for the design of the liner and the
performance of the bentonite seal at the base of the lining, a key design consideration.
Laboratory testing included large shear box and tilting table testing. It is recommended that this
type of testing should be used more in New Zealand.

Civil works design and construction challenges for the Catuiran hydropower project, The Philippines

Author

Grimston, John O. & Ortigas, N.M. (2015)

Source

Hydro 2015 Conference, 2015, Bordeaux

Year

2015

Catuiran Hydro-electric Power Project is a renewable energy small hydro power development based on run-of-river operation. Although in the mini hydro power category, the project provides excellent specific examples of many technical challenges faced by hydropower developments in developing countries with extreme meteorology and hydrology, seismically active environments and complex geological conditions. Innovation and design flexibility is necessary to address these technical, as well as social and economic challenges and are part of the landscape for such projects in the Philippines in an ever developing and changing environment.

Urban stream restoration - erosion control and fish habitat engineering

Author

Quilter, Bryn

Source

Water NZ Stormwater Conference Christchurch 2014

Year

2014

The Mangakotukutuku Gully is located on the south western side of the Hamilton urban area and represents one of six urban gully systems with a connection to the Waikato River within Hamilton City. The Mangakotukutuku Stream Care Group (MSCG) was established in 2006 in response to community concerns about the poor health of Mangakotukutuku Stream and the lack of attention being given to its ecological values. Tonkin + Taylor (T+T) has worked with MSCG since 2008 in developing restoration demonstration sites aimed at improving the health of the stream whilst engaging with and educating the local community. T&T has developed four individual reach restoration plans and implemented physical works for two of those plans. This paper presents engineering design and construction issues associated with physical works for an offline mini wetland intended as native mudfish habitat, three different stream bank re-grading options incorporating soil filled containers, woody weirs for flow diversity, log overhangs, and novel stream bank fish refuge habitats targeting tuna (eel) and giant kokopu. The paper presents key learnings including: soil container construction, advantages and disadvantages of the three bank re-grading options used, potential for community construction initiatives, construction of fish refuge habitats, woody weirs and log overhangs, and effects of sedimentation on those features. The performance of the stream bank erosion mat product used and associated variable vegetation uptake on the stream banks is also discussed. A design calculation method for anchored woody in-stream structures is also presented.

Application of modern dam safety management practices to older farm dams

Author

Duder, John N.; Bouma, David; McCallum, Paul D.

Source

NZSOLD/ANCOLD Conference November 2013

Year

2013

The authors have been involved in the safety inspection and remediation of many older (pre-dating the 2004 Building Act) farm dams over the past decade. This paper presents a summary of the varied benefits and risks of these older dams and the difficulties encountered in bringing them into alignment with current practice. The many farm dams around New Zealand provide considerable benefit to the owners and often to the environment and wider community including the obvious stock water and irrigation, but also micro hydro, recreation, flood detention, release of environmental flows and flows for downstream users, and wetland habitat. However, when applying current dam safety practice, and looking forward to the implementation of the Dam Safety Regulations, some of the older farm dams have significant dam safety issues that are often challenging to address. Although there is a high degree of variability, typical issues include: • Little or no documentation of geotechnical investigations, design or construction • Design standards, particularly for spillway capacity have generally increased • Little or no formal surveillance or maintenance carried out or recorded since commissioning • Many farm dam owners have a poor understanding of their obligations under the Building Act and the Conditions of their Resource consents • Consent conditions may not require dam safety related monitoring and maintenance, and/or the conditions may not have been historically enforced.

Increased flooding vulnerability lessons learned in assessing the effects of flooding caused by the Canterbury Earthquake Sequence

Author

Taylor, Mark C.N. , Fisher, Tim S.R. , Ng, Kevin & Pennington, Mark

Source

ICONHIC 2016 1st International Conference on Natural Hazards and Infrastructure, Chania, Greece

Year

2016

The Canterbury Earthquake Sequence (2010 – 2011) caused significant damage and loss of life in Christchurch, New Zealand. The Earthquake Commission (EQC) is New Zealand’s public insurer for natural disaster damage. EQC determined that a new, claimable form of land damage had resulted due to the Increased Flooding Vulnerability (IFV) caused by the subsidence of the land changing the flood risk to residential properties. Tonkin + Taylor (T+T) on behalf of EQC had by early 2016 completed engineering assessments of over 11,000 residential properties in Canterbury. The purpose of the assessments was to understand and quantify the effects on residential properties of IFV caused by the Canterbury Earthquake Sequence during 2010 and 2011. The completion of these assessments has involved over 75,000 man hours and is the culmination of 5 years of data collection, policy and methodology development, legal and peer review. It is also largely due to the dedication of a team of up to 100 engineers and scientists at T+T to assess and document the effects of what is now recognised as one of the largest insurance events in the worlds history. This paper builds on earlier papers that focused on the policy and methodology, and on the flood models developed for the study. This papers examines some of the engineering challenges and how they were dealt with. It also considers what lessons could be learned if the process was to be repeated. The key issues that the team encountered and will be documented in this paper are the importance of robust policy/methodology development, data collection/limitations and sharing, scoping models for the project purpose, the application of engineering judgment to complex/multiple source of information, the requirement for accurate location management, the large IT support systems required, and the communication with stakeholders and the public.

A regional study of water storage options in the Wairarapa

Author

Bassett-Foss, Michael , Bouma, David & Knappstein, Dewi (2015)

Source

ANCOLD (Australia National Committee on Large Dams) Conference, 2015, Brisbane

Year

2015

The Wairarapa Water Use Project (WWUP) in the southern North Island, New Zealand, is investigating new water storage schemes involving large dams that will allow the community to make use of the water resources that are currently available, but not necessarily available at the time they are needed. It is estimated that the 12,000 hectares currently irrigated in the Wairarapa could be increased to about 42,000 hectares depending on actual demand. The WWUP provides for a range of possible needs, such as supply of new areas of irrigation, increased reliability for existing irrigation and frost fighting, environmental augmentation of low summer river flows, environmental flushing flows, stock drinking water, power generation, municipal water supply, and recreational use.
WWUP objectives include early engagement of stakeholders, early integration of financial, social, cultural and environmental factors in decision-making, management of uncertainty associated with the preliminary level of investigation and evolving regulatory framework, development of an equitable framework for efficiently comparing options, and balancing long and short-term considerations.
A large number of dam options were identified, storing 3 to 80 million m3 of water, and progressively narrowed to a shortlist of 2 sites through a complex process of concept development, desktop studies, site visits, hydrological analyses, cost estimates and multi-criteria analyses.
The WWUP demonstrates how sustainable new major water storage schemes can be promoted in a highly regulated environment of a developed nation

CFD modelling of stormwater overland flow at the entrance to a road underpass

Author

Heays, Katherine G. , Reed, Sam M. & Fisher, Tim S.R. (2013)

Source

8th South Pacific Stormwater Conference, 2013, Auckland

Year

2013

The Buckle Street underpass is part of the Memorial Park project being delivered by the Memorial Park Alliance. Investigations of stormwater systems for the proposed Buckle Street underpass indicated that overland flows posed a flood risk to the underpass. Star CCM+ Computational Fluid Dynamics (CFD) software was used to model the stormwater flow through the intersection. The flow of water entering and bypassing the underpass was quantified.
The site is located at the intersection of Taranaki, Buckle and Arthur Streets, Wellington. The Taranaki Street catchment above the intersection is 23.3 ha and relatively steep with a high proportion of impervious surfaces. The overland flows entering the intersection were predicted to be 5.4 m3/s. Some of the overland flow from Taranaki Street will be diverted down the underpass. The design of the intersection and underpass drainage has been designed to accommodate these overland flows.
CFD modelling was undertaken to refine the intersection surface design, to assist in striking the best balance between a safe road alignment and flood protection. The exact nature of CFD modelling allows the evaluation of the effect of small changes in camber on the volume of water entering the underpass. The results from this study show an encouraging progression in the application of CFD to complex overland flow applications in engineering.

Increased flooding vulnerability : the methodology and flood models to assess 120,000 properties in Christchurch (1)

Author

Taylor, Mark C.N. , Fisher, Tim S.R. , Pennington, Mark , Ng, Kevin & Jackson, Matt (2015)

Source

Asia Pacific International Stormwater Conference, 2015, Auckland (Water New Zealand)

Year

2015

An overland flow model of the whole of Christchurch was developed by Tonkin & Taylor (T&T) on behalf of the Earthquake Commission (EQC) in TUFLOW 2D software. The model results are applied to the assessment of Increased Flood Vulnerability (IFV) that is defined by EQC as a physical change to residential land as a result of subsidence due to the Canterbury earthquake sequence, which adversely affects the amenity and value that could otherwise be associated with the land by increasing the vulnerability of that land to flooding events. This form of land damage has never been assessed before in the world and the technical (including modelling) response has been unique and unprecedented.
The overland flow model covers the entire urban area of Christchurch City. It can be split into component models covering the individual catchments of the Avon, Heathcote and Styx Rivers if required, but can also be run as a single city-wide model. The city-wide model has benefits in extreme events as cross-catchment flows, which occur in Christchurch due to the flat terrain, can be represented. This model is currently being used to assess and identify (out of all 120,000 properties in Christchurch) approximately 13,500 potential IFV properties that will then have a site specific engineering assessment to confirm their status.
This paper describes the model build of the Christchurch overland model, its sensitivity testing, calibration using the 4 and 5 March 2014 flood event and also its application in assessing IFV. This paper also describes the additional work currently in progress to construct a model to assess IFV for Kaiapoi and adjoining residential areas north of the Waimakariri River.
KEYWORDS
Flood, Model, Overland, Christchurch, Kaiapoi, Earthquake

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