David Leong - Appendix 1 - Environment Canterbury

TONKIN & TAYLOR LTD 

Environmental and Engineering Consultants 

TONKIN & TAYLOR LTD CURRICULUM VITAE 

David Leong 

Education 

Master of Engineering (Distinction), Civil, 1988, University of Canterbury 

Bachelor of Engineering (Hons 1 st Class), Civil, 1987, University of Canterbury 

Professional Affiliations 

Chartered Professional Engineer, CPEng (NZ) 

International Professional Engineer, IntPE (NZ) 

Member, Institution of Professional Engineers NZ 

Member (and former Executive Committee), NZ Hydrological Society 

Employment Record 

Tonkin & Taylor Ltd, Auckland 

2000 to present 

Environment Asia Sdn Bhd, 

Kuala Lumpur, 1998 to 2000 

Tonkin & Taylor Ltd, Auckland 

1990 to 1997 

Hydrology Centre, Ministry of 

Works, Christchurch (now part 

of NIWA), 1988 to 1990 

Director (from 2009) and Senior Water Resources Engineer 

Senior Water Resources Consultant 

Principal (from 1994) and Senior Hydrologist 

Research Engineer 

Sample Project Experience 

Water Supply and Irrigation 

 

Hunter Downs Irrigation Scheme, Waitaki River 

Environment Canterbury, 2007 

Peer Reviewer 

Review of the hydrological effects from the proposed take and use by the South Canterbury Irrigation Trust 

and Meridian Energy of up to 20.5 m 3 /s of water from the Waitaki River for irrigation of up to 40,000 

hectares of land in the Waimate and Timaru Districts. 

• Lee River Dam Feasibility (Waimea Plains Water Augmentation Study Phase 2) 

Waimea Water Augmentation Committee/Tasman District Council, 2007-2009 

Project Manager for Hydrological Components 

For this feasibility study of a 50 m high dam on the upper Lee River responsible for the following: 

- Confirmation of projected water demands for irrigation and urban/industrial needs 

- Analysis of the surface water and groundwater interaction in the Waimea Plains 

- Assessment of zone of supply, extended distribution system and confirmation of storage requirements 

- Flood hydrology, dam spillway design and hydro-energy assessment 

- Detailed dambreak hazard assessment and mapping using a 2-D hydraulic model 

1 

David Leong



• Integrated Source Management Model for Auckland’s Bulk Water Supply 

Watercare Services Ltd, 1999-2003 & 2008 

Technical Leader and Senior Hydrologist 

Responsible for developing, calibrating and implementing the Integrated Source Management Model. The 

model covered all of Watercare Services Ltd’s bulk water sources and treatment facilities (bulk treated 

water delivered about 300,000 m 3 /day), and determined the optimal proportions of demand to be met from 

each source, including the (then) proposed Waikato River intake (75,000 m 3 /day). 

Winner of IPENZ Supreme Award for Engineering Excellence 2003 

• Waitaki Water Allocation Plan 

Ministry for the Environment, 2005 

Senior Hydrologist 

Preparation of a report on the hydrological information of the Waitaki catchment to support the Waitaki 

Catchment Water Allocation Regional Plan process, including development of a method for assessing 

surface water take reliability for the main stem of the river and its tributaries. 

• Waitakere Water Supply Infrastructure Consents 

Watercare Services Limited, 1999-2005 


Responsible for assessing hydrological effects of the water supply infrastructure in the Waitakere Ranges, 

consisting mainly of the upper and lower Nihotupu dams, upper and lower Huia dams and the Waitakere 

dam. This study involved detailed simulation of natural river inflows, preparation of supporting 

documentation for consents renewal, and presentation of expert evidence in a hearing, which had a positive 

outcome for Watercare Services Ltd. 

• Barrhill-Chertsey Irrigation Scheme Intake 

Barrhill Chertsey Irrigation Company, 2003 

Project Manager and Senior Engineer 

Responsible for feasibility design of the river intake structures of the Barrhill Chertsey Irrigation Scheme 

located on the Rakaia River 6 km downstream of SH77. The intake has a diversion capacity of 40 m 3 /s and 

a drawoff capacity of 17 m 3 /s, and includes design features which are ‘fish-friendly’, reduce bedload 

ingestion, protect against scour/undermining, reduce blockage risk by sediment and floating debris, and 

allow it to operate through a wide range of river flows. It includes provisions for manual sediment removal 

as well as sluicing during high flows, screens for fish exclusion, and a vertical slot fish pass and special fish 

access channel for passage of upstream migrating salmonids. 

• Omaka Downs Irrigation Dam 

Landco Ltd, 2007-2008 


Developed a detailed hydrological model of the proposed operation of the Omaka Downs irrigation dam 

(Marlborough) incorporating 46 years of Wairau and Waihopai River flow data, the suite of 10 existing 

and proposed consented takes, 7 supply zones with varying demand requirements, and water allocation 

plan rules. Subsequently presented evidence at consent hearing in relation to dam storage requirements, 

drought security, and effects on other water users. 

• Kainui Community Dam (Wai-iti Dam) 

Tasman District Council, 2002 -2003 

Senior Hydrologist / Hydraulics Engineer 

Responsible for assessment of catchment hydrology and water storage requirements for an off-river storage 

dam in the Wai-iti catchment south of Richmond. Also undertook dam break modelling and hazard 

mapping for the dam. 

• Auckland Water Supply Dams Spillway Rating Curves 

Watercare Services Limited, 2005 

Project Manager and Hydraulic Engineer 

Responsible for revising and updating the spillway level-discharge rating curves for all ten water supply 

dams in the Auckland region, with emphasis on the accuracy of the low to medium flow range. 

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• Auckland Water Supply Dams Inflow Calculation 

Watercare Services Limited, 2005 


Responsible for developing an advanced algorithm and software for computing smoothed and realistic 

inflows for all ten water supply dams based on recorded lake levels and supply draw-off. 

• Sg Kinta Water Supply Intake Sediment Management 

Metropolitan Utilities Corporation, 1999-2000 

Senior Engineer and Hydrologist 

Assessed the sedimentation regime of Sg Kinta (in Perak, Malaysia) above the MUC water supply intake, 

identified the quantum of siltation from construction activities within the catchment, and recommended 

short and long term strategies for overcoming excessive bedload and turbidity problems. 

• Wairoa River Infrastructure Consents 

Watercare Services Limited 


Responsible for assessing hydrological effects of the water supply infrastructure in the Wairoa River 

catchment which consists of the Wairoa and Cosseys Dams and which have a combined yield of about 55 

million litres/day. This study for Watercare Services Ltd provided supporting documentation for consents 

renewal, and involved detailed simulation of natural river inflows. 

• Whitianga Future Water Source Study 

Thames Coromandel District Council 


Responsible for hydrological studies for Whitianga township future bulk water supply sources covering 

both storage and run-of-river schemes, followed by hydraulic analysis and design flood level assessment 

for proposed water supply intake on the Whangamaroro River. 

• Maniototo Irrigation Dam 

Attewell Irrigation Consultants 


Reviewed the flood hydrology and freeboard adequacy for the Maniototo irrigation dam in Central Otago, 

and recommended options to improve spillway capacity. 

• Rangitata River Irrigation Enhancement 

Mid-Canterbury Irrigation Enhancement Society 


Scoping study for a series of possible schemes, comprising dams, river intakes and diversions, to increase 

the irrigation area commanded by the Rangitata Diversion Race from 70,000 hectares currently to a 

maximum development scenario of 160,000 hectares. Potential hydroenergy generation at irrigation 

headworks was evaluated for all options. 

• Auckland Water Supply Emergency Enhancement Measures 

Auckland Regional Council, 1994-1995 

Project Manager and Senior Hydrologist 

Responsible for surface water resource evaluations for augmenting Auckland’s bulk water supply system to 

weather the 1994 drought. Streams studied included the Wairoa River, on which a 30,000 m 3 /day 

emergency intake and pumpstation were built, the Mangatawhiri Stream and some 15 other potential intake 

sites around the Auckland. 

• Great Mercury Island Water Supply 

Hydrologist / Engineer 

Pipeline and pump design and contract specification for water supply development project on Great 

Mercury Island, Hauraki Gulf. 

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• Auckland Future Bulk Water Supply Options Study 

Auckland Regional Council, 1995 


As part of the 1995 study of future bulk water supply options for Auckland, evaluated the water resources 

and dry weather flows from small streams in the greater Auckland Region for a variety of drought standards 

and residual flow options. 

• Blowing Point Dam Feasibility 


Senior Hydrologist / Hydraulic Engineer 

Assessed, to feasibility level, the hydrology of the South Ashburton River dam option (130 million m 3 

storage) to augment irrigation supply from Rangitata Diversion Race. Potential hydropower from the 

proposed dam and augmentation of the energy output from the Highbank Power Station were also 

investigated. 

• Mangakahia River Irrigation Consents 

Mangakahia Irrigation Committee, 1992-1994 

Project Manager and Hydrologist / Hydraulic Engineer 

Managed a study of low flows and environmental effects for proposed large scale pasture irrigation in the 

Mangakahia River catchment, Northland. Presented expert evidence in the consent hearing and, 

subsequently, in the Planning Tribunal in support of applications to extract water. Landmark decision 

subsequently awarded in applicants’ favour. 

• Kakanui / Waiareka River Irrigation Study 


Responsible for hydrological analysis and dam storage modelling for the Kakanui/Waiareka River 

irrigation project (Otago) to establish storage requirements and sensitivity to residual flow criteria. Onriver 

storage, off-river diversion storage and pumped diversion scheme options were investigated. 

Hydro-electric Power 

 

Patea Hydroelectric Power Scheme Re-consenting 

TrustPower Limited, 2005–2008 


Responsible for hydrological investigations and effects assessment in support of the application to renew 

consents for this 65m high dam which has a 31MW power station on the Patea River in Taranaki. Review 

of flood hydrology, the Probable Maximum Flood (PMF) and capacity of spillways. Dambreak hazard 

assessment and mapping for both flood-induced failure and sunny-day failure. Review of historical 

operation and consent compliance, and effects of daily peaking on river flow regime. 

 

Project Aqua 

Meridian Energy, 2000–2004 

Team Leader Hydrology and Hydraulics 

Project Aqua is a cascade-type hydroelectric power scheme based on the Waitaki River, with an innovative 

low profile river intake, 64 km of canals and six power stations. The design flow is 340 m 3 /s with 

generation capacity of 530 MW, and an annual output of about 3200 GWh. Project responsibilities (at 

preliminary design phase) included: 

- Co-ordination of all hydrological and hydraulic design aspects 

- River intake, canal intake and river outfall design 

- Hydrology and assessment of long term flow trends 

- Morphological aspects at river intake and outfalls, and assessment of bed and suspended load 

- Preliminary assessment of hydroenergy output and peaking potential 

- Assessment of overall scheme hydraulics, including transient conditions, and headlosses 

- Interaction with various environmental consultants, particularly with regard to fish and habitat 

protection, and with Electrical & Mechanical consultants. 

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Vaita’i Hydropower Scheme, Samoa 

Asian Development Bank, 2007 


Responsible for data interpretation, hydrological analysis and derivation of flow duration data for 1.8 MW 

run-of-river scheme in the island of Savai’i, Samoa. 

Wahapo Hydroelectric Power Scheme Re-consenting 

TrustPower Limited, 2007–2008 


Responsible for hydrological investigations and effects assessment in support of the application to renew 

consents for this 3.1 MW hydro-electric power scheme in South Westland. 

Ambuklao and Binga Hydroelectric Power Scheme Remediation Project 

SN Aboitiz Power (Philippines), 2008 

Team Leader and Senior Hydrologist/Hydraulic Engineer 

Responsible for preparation of the Operation, Maintenance and Surveillance Manual for the 75 MW 

Ambuklao scheme which includes a 130 high dam and the 100 MW Binga scheme which includes a 107 m 

high dam, both on the Agno River in Luzon, Philippines. Responsible also for drafting the Emergency 

Action Plan for these two dams which are in cascade, and dambreak hazard assessment and mapping. 

Review of the Probable Maximum Flood for Binga Dam (11,600 m 3 /s) and adequacy of its gated spillway. 

Pantabangan Dam Flood Review 

FirstGen (Philippines), 2008 


Detailed review of flood hydrology and the Probable Maximum Precipitation (PMP) and Probable 

Maximum Flood (PMF) for this 107 m high irrigation and hydropower dam on the Pampanga River in 

central Luzon (Philippines). The dam’s reservoir has a live storage capacity of 1750 million m 3 and a peak 

inflow in excess of 12,000 m 3 /s. 

Angat Dam 1 st Phase Due Diligence 

Manila Oslo Renewable Energy (Philippines), 2008 


Assessment of flood hydrology and spillway adequacy for this 130 m high water supply, irrigation and 

hydro-electric power dam, and scoping of remedial works and potential enhancement options. 

North Bank Tunnel Concept, Waitaki River 

Environment Canterbury, 2007 

Peer Reviewer 

Review of the hydrological effects from the proposed take, use and discharge up to 260 m 3 /s of water from 

the Waitaki River for hydroelectricity generation via this tunnel-based scheme proposed by Meridian 

Energy. 

Opuha Dam 

Doug Hood Ltd, 1995-1997 

Senior Hydrologist/Hydraulic Engineer 

Responsible for detailed hydraulic design of spillways, tailrace excavation and hydraulic structures for 50 

m high combined irrigation and hydro (7.5 MW) dam on the Opuha River, South Canterbury. Also 

responsible for hydro-energy modeling and output evaluation, and involved in planning operational 

strategy. 

Aratiatia Power Station 

Mighty River Power Ltd, 1997 


Designed remedial works, prepared contract documents and managed construction contract for repair of 

erosion damage to left bank of the tailrace of the 80 MW Aratiatia Power Station. Concurrently also 

responsible for contract for dredging accumulated sediment in the upstream river channel and intake 

forebay of the power station. 

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Hydropower Potential of State-Owned Dams in Queensland 

State Water Projects, Queensland, 1998-1999 


Responsible for evaluating the hydroenergy potential of retro-fitting power stations to 42 existing weir and 

dam structures in Queensland, Australia for State Water Projects department, including identification of 

peaking potential, flooding effects, constraints on development and potential enhancements or operational 

modifications to increase energy generation. The structures comprised mainly irrigation weirs and dams, 

and a few water supply dams. 

Butwal Power Company Due Diligence, Nepal 

Confidential Client, 2002 


Responsible for the assessment of hydroenergy output from existing power stations: Khimti 1 (60 MW), 

Jhimruk (12 MW) and Andikhola (5 MW) in Nepal for a due diligence assessment. 

• Southern Hydro Due Diligence, Australia 

Confidential Client, 1997-1999 


Retained as an Independent hydrology/hydroenergy reviewer by confidential client in the funding of the 

purchase of a group of hydropower cascade schemes (total 500 MW) in Victoria, Australia, including the 

Eildon, Dartmouth, Kiewa, Rubicon and Cairn Curren stations. 

 

 

Lake Coleridge Hydropower Due Diligence 

Confidential Client, 1998 


Due diligence investigations, incorporating detailed hydroenergy modelling, for the 37 MW Coleridge 

Power Station in the headwaters of the Rakaia River for confidential client. Investigations included the 

evaluation of various enhancement works and changes to current operational strategy. 

Wairua Falls Power Station Refurbishment 

Northpower Ltd 

Senior Engineer 

Established hydraulic performance characteristics for the intake barrage for the Wairua Falls Power Station 

(Northland Region), and designed a bypass gabion structure for extreme flood conditions 

• Kioreweku Hydro Scheme Feasibility 

Bay of Plenty Electricity 


Responsible for hydroenergy assessment, tailrace design optimisation, feasibility design of intake gate 

structure and energy dissipating structures for the 13 MW Kioreweku hydro scheme on the Rangitaiki 

River (Bay of Plenty), including the design of an artificial canoe course proposed as an environmental 

mitigation measure. 

 

Tailwater Lowering Cost Assessment 



Project managed a re-assessment of construction costs and an appraisal of environmental issues for 

lowering the tailwater (in order to increase generating head) at three of Mighty River Power’s existing 

power stations, Aratiatia, Karapiro and Atiamuri. 

• Highbank Power Station Hydroenergy Assessment 



Assessed potential energy output enhancement at the 25 MW Highbank Power Station from optimised 

irrigation race operations and through construction of additional stream intakes and a large storage dam 

within one of the system sources. Testing of variables such as dam storage, irrigation demand, intake 

capacities and operational strategy. 

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• Aviemore Power Station 

ECNZ, 1994 


Responsible for hydraulic modelling and identifying options for possible tailwater lowering for the 220 

MW Aviemore Power Station. Study to prefeasibility level was aimed at assessing excavation costs 

against improvement in station output resulting from increase in generating head. 

• Komarindi Hydropower Project, Solomon Islands 

Asian Development Bank 

Hydrologist / Hydraulic Engineer 

Responsible for hydrological analysis and hydraulic scale model testing for the final design phase of the 8 

MW Komarindi Hydropower Project in the Solomon Islands. 

Dam Safety Evaluation & Dam Break 

• Omaka Downs Irrigation Dam 

Landco Ltd, 2002 & 2007-2008 

Senior Hydraulic Engineer 

Dam break modelling and hazard mapping for the proposed 5 million m 3 Omaka Downs dam in the 

Marlborough District, including preliminary design of mitigation measures to reduce the potential impact 

from a dam breach. Subsequently, for an enlarged 18 million m 3 dam option at the same site, a 2-D model 

(DHI’s MIKE21) was used to model the potential downstream flood hazard, and detailed contour maps of 

flow depth, flow velocity and their product were produced. Presented evidence at consent hearing in 

relation to dambreak hazard. 

• Ambuklao and Binga Hydroelectric Power Scheme Remediation Project 

SN Aboitiz Power (Philippines), 2008 

Team Leader 

Responsible for dambreak hazard assessment and drafting the Emergency Action Plan for two large dams 

in cascade on the Agno River in Luzon, Philippines: the 130 m high Ambuklao dam and the 107 m high 

Binga dam downstream. 

• Kinleith Dam 19 Comprehensive Safety Review 

Carter Holt Harvey, 2007 


Assessment of flood hydrology and spillway adequacy, and review of dambreak hazard assessment. 

• Kaituna River Hydropower Scheme Hazard Assessment 

Todd Energy, 2005 

Senior Hydraulic Engineer/Hydrologist 

Responsible for dambreak hazard assessment for the existing lake control gates and the intake dam 

downstream of the gates for this proposed hydropower scheme in the central North Island, plus review of 

hydro-energy. 

• Opuha Dam Break Hazard Mapping 

Networks South Ltd, 2003-2004 

Project Manager and Senior Hydrologist / Hydraulics Engineer 

Dam break modelling of the existing 50m high, 90 million m 3 multi-purpose Opuha Dam (irrigation, hydro 

and environmental enhancement) for various seismic and PMF failure scenarios. This was followed by 

hydraulic modelling of the floodpath to map potential inundation area to the coast. A one dimensional 

dynamic model (MIKE11) used for the upper valley and two dimensional model results (Hydro 2de) used 

to delineate hazard zone in the very wide lower floodplain. 

• Project Black Point 

North Otago Irrigation Company, 2006 


Canal breach hazard analysis for an irrigation water transfer project in the North Otago region which 

includes a 3km long earth lined canal. The elevated canal conveys up to 8 m 3 /s of Waitaki River water to 

the Waiareka and Kakanui valleys to the south. 

7 




• Waima Irrigation Dam 

Peter Yealands Group, 2006 


Responsible for dambreak hazard analysis for this proposed 20 m high irrigation dam on the Waima River 

near Ward, Marlborough, and assessment of the Potential Impact Category per the NZSOLD Guidelines. 

• Kinleith Dam 22: Dam Failure Analysis 

Carter Holt Harvey, 2003-2004 


Post-event analysis of the breach Dam 22, a 5 m high dam within the effluent system of the Kinleith pulp 

and paper mill, on 11 December 2003. The analysis included an investigation of the storm event, the 

catchment’s response to rainfall, the performance of the spillways of the dams in the cascade, peak 

discharge during the breach, and the impact on the downstream environment. 

• Upper and Lower Turitea Dams Safety Evaluation 

Palmerston North City Council, 2001-2002 

Project Manager and Senior Hydrologist/Hydraulic Engineer 

Stage 2 SEED for the Upper and Lower Turitea water supply dams focussing on adequacy of spillway 

capacity, hydraulic performance and potential to undermine dam, followed by dam break hazard mapping 

using MIKE11 hydrodynamic model. 

• Delta Irrigation Dam 

Marlborough Water Augmentation Group, 2002 


Dam break modelling and hazard mapping for the proposed Delta Irrigation Dam south-west of Blenheim. 

Two dam options (1 and 4 million m 3 storage capacities) were asessed, with study results included with 

applications for consents. 

• Kainui Community Dam 

Tasman District Council, 2002 


Dam break modelling and hazard mapping for a proposed small off-river irrigation storage dam in the Waiiti 

catchment south of Richmond. 

• Upper and Lower Nihotupu Dams SEED 

Watercare Services Ltd, 1997 

Senior Hydrologist/Hydraulic Engineer 

In the Stage 1 SEED, assessed flood flows, spillway adequacy and dam overtopping hazards for the Upper 

Nihotupu Dam (Auckland Region). Stage 2 SEED involved dam break analyses of the Upper and Lower 

Nihotupu Dams. 

• Layang Water Supply Dam 

Generale Des Eaux, 1995 

Hydrologist / Hydraulics Engineer 

Reviewed the flood hydrology and the planned implementation of Hydroplus fuse gates at the Layang water 

supply dam, Johor (Malaysia), and made recommendations to modify the fuse gates to limit damage to 

spillway structure on fusing. 

Eco-Hydraulics 

• Ribb River Irrigation Dam, Ethiopia 

Ministry of Water Resources, Ethiopia, 2008 

Senior Water Resources Engineer 

Assessment of the impact on fisheries of a 73 m high irrigation dam (under construction) on the Ribb 

River, a tributary of the Blue Nile. Responsible for predicting hydrological alterations from construction 

and operation of the dam, for identifying riparian measures to mitigate adverse effects and enhance 

existing habitats, and for recommending changes to the design (e.g. intake and flushing facilities) and 

operation (e.g. release flow regime) of the dam. 

8 




• ALPURT B2 Northern Motorway Extension Fish Passage 

Northern Gateway Alliance, 2004-2007 

Drainage Design Team Leader 

Responsible for designing culverts that facilitated passage of native fish. The innovative use of artificial 

pool-riffle structures within culverts that not only facilitated native fish passage but also created in-culvert 

habitat opportunities. 

• Southern Sockeye Salmon Insurance Claim 

Lloyds of London, 1999-2000 


Investigation of salmon losses in the Ohau Channel salmon farm, focusing on hydrological issues, 

including preparation of expert evidence for High Court hearing, for insurers (Lloyds of London). 

• Mangakotukutuku Stream Diversion 

Solid Energy, 2003 & 2006 


Concept and feasibility design for a 1.4 km stream diversion to facilitate development of the Awaroa 4 

open cast coal mine near Huntly. The design waterway comprises a three-stage section, based on an 

design philosophy to improve the degraded natural habitat. The low flow channel has pool, riffle and run 

habitats with appropriately vegetated riparian margins. Subsequently involved in technical advisory role 

during detailed design and construction. Winning project of Arthur Mead Environmental Award 2007. 

• Hays Creek Dam Fish Passage 

Watercare Services Ltd, 2005 


Responsible for design and contract documentation for construction of a native fish pass and flow 

monitoring weir at the Hays Creek Dam access road. 

Roading, Landfill, and Other Infrastructure Drainage 

• Tauranga Harbour Link Stage 2 

Fletcher Construction Ltd, 2006 – 2008 


Responsible for tender design, detailed design and construction monitoring for all stormwater drainage 

works, including stormwater treatment, for the Tauranga Harbour Link Stage 2 project. This $131 million 

project is the largest transport project in the Bay of Plenty, and involves construction of a continuous four 

lane expressway from Takitimu Drive in Tauranga through to Mount Maunganui, including a duplicate 

Harbour Bridge and a four lane flyover from Takitimu Drive to the existing Harbour Bridge. 

• ALPURT B2 State Highway 1 Northern Motorway Extension 

Northern Gateway Alliance, 2004 – 2007 


Responsible for delivery of concept through to detailed design and construction monitoring for all 

stormwater drainage works for a 7.5 km length of motorway between Orewa and Puhoi townships north of 

Auckland. This $359 million project, the largest single roading contract in New Zealand, is being 

constructed under a project alliance structure incorporating Transit New Zealand, constructors, project 

manager and designers. Stormwater drainage works for the motorway, which traverses through steep 

terrain with several difficult geological formations, high storm rainfall intensity and a sensitive 

environment with high ecological value, include the following: 

- 16 km of networked stormwater pipes 

- 9 permanent stormwater quality and flood attenuation ponds 

- numerous other temporary erosion and sediment control ponds and devices 

- 6 major culverts up to 2.1 m diameter under fill embankments up to 35 m high 

9 




• Bukit Tagar Landfill, Klang Valley, Malaysia 

Berjaya Corporation Limited, 2004 


Responsible for a detailed hydrological impact assessment and the stormwater drainage master plan for this 

large and modern landfill located 50 km north of Kuala Lumpur. The landfill has a 260 hectare footprint 

and capacity for 120 million tonnes of refuse, sufficient to handle the entire solid waste generated in Kuala 

Lumpur and Selangor for the next 50 years. This project won the 2008 Institute of Engineers Malaysia’s 

Outstanding Engineering Award and the 2008 Association of Consulting Engineers of Malaysia’s Gold 

Medal Award. 

• South Coast and East Coast Roads, Western Samoa 

Downer Construction, 1997 


Responsible for hydrological design and detailed drainage design of culverts and fords for 22 km of 

roading for the island of Upolu, Western Samoa in design-build contract. 

• Silverstream Landfill 

Hutt City Council, 2003-2004 


Responsible for design of overall drainage concept, individual drainage elements (including diversion 

channels, drop structures, berm drains, culverts and energy dissipating structures) and sedimentation ponds 

for the Silverstream landfill in Upper Hutt. 

• Kate Valley Landfill 

Transwaste Canterbury Ltd, 2001 & 2004 


Review of site hydrology (Kate Creek) and water source and storage options for construction water supply. 

Review of hydrological design of the water supply dam and silt dam. 

• Grey River Rail Bridge 

Tranz Rail Ltd, 1996-2004 


Reviewed flood hydrology of the Grey River and assessed hydraulic impacts, particularly backwater 

effects, of the proposed replacement rail bridge crossing of the Grey River, Greymouth. Pier scour 

computations, for both the existing and replacement bridges, and abutment protection design. 

• Redvale Sanitary Landfill: River Flow Monitoring Station 

Waste Management New Zealand Ltd 


Site investigation, design and specification of a permanent flow monitoring station on the Rangitopuni 

Stream below the Dairy Flat landfill, Rodney. 

• Puwera Landfill 

Whangarei District Council, 2000-2001 


Design of overall drainage concept, individual drainage elements (diversion channels, drop structures, 

berm drains, culverts, etc) and sedimentation ponds for proposed Puwera landfill near Whangarei. 

 

Cypress Coalfield Development 

West Coast Regional Council, 2004 

Peer Reviewer Hydrology 

Review of Solid Energy’s assessment of hydrological effects in its consent develop and operate an open 

cast coal mine within the Waimangaroa Mining Permit Area on the West Coast of the South Island. The 

hydrological component of the review considered water quality, water management and dam safety aspects 

(St Patricks Dam). 

10 




• State Highway 1 Realignment Albany to Puhoi (ALPURT) AEE 

Transit New Zealand, 1992-1996 


Managed the hydrology and water quality aspect of the Assessment of Environmental Effects (AEE) for 

the proposed SH1 realignment between Albany and Puhoi, and subsequently presented evidence in the 

designation hearing in support of Transit’s application, both at Consent Hearing and Environment Court 

levels. Also managed a study to establish appropriate water quality discharge standards from roadworks 

silt control devices, and developed an erosion and silt control plan for the earthworks within the steep 

Waiwera valley south of Puhoi. Asessed potential environmental impacts of discharges from earthworks. 

• Central Link Expressway, Malaysia 


Responsible for effects assessment of the North-South Expressway Central Link on the hydrology of the 

Kuala Langat North Peat Swamp Forest and recommended measures to mitigate effects and lessen the risk 

of peat fires. 

• State Highway 20 

Fulton Hogan 


Responsible for hydrological studies and stormwater trunk drainage design for the Mangere Motorway 

Extension (SH20) design-build project. Also assessed stormwater quality treatment requirements for the 

motorway in accordance with ARC’s Stormwater Treatment Devices guideline manual. 

• Mangere Sewage Treatment Plant Tender Design 


Responsible for hydraulic aspects of the tender design of the Mangere Sewage Treatment Plant ocean 

outfall diffuser, the tide gate structure on the Oruarangi Creek and the tidal waterway at the Sludge Lagoon 

entrance, and developed innovative outfall discharge solutions which did not require pumping. 

• Mines Theme Park Development, Malaysia 


Conducted hydrological and flood routing study of two large disused tin mine lakes to be used as 

recreational lakes in the Mines Theme Park Development south of Kuala Lumpur (Malaysia). Developed 

operational strategy and design parameters for the canal and boatlift structure that linked the two lakes 

which had a 6 m water level difference. 

Catchment Management & Flood Control 

• Tauranga-Taupo River Flood Management Project 

Environment Waikato 2002-2004 

Project Manager and Hydraulic Engineer 

Responsible for hydraulic modelling and regime analysis of the Tauranga-Taupo River, including design of 

overflow floodway (Kiko Spillway), river bed controls and flood protection works. 

• Waikato River Flood Rules Review 


Peer Reviewer 

Peer review of the modelling and review of flood operational rules for the hydro-electric power 

infrastructure on the Waikato River. 

• Sg Kinta Flood Mitigation Project 

Department of Irrigation & Drainage, Malaysia, 1998-2000 

Team Leader and Senior Hydrologist/Hydraulic Engineer 

Responsible for hydrological modelling, hydraulic modelling and assessment of flood mitigation measures 

for Kinta River Major Flood Mitigation Project which includes detailed design of mitigation measures for 

Kinta River, which drains 2540 km 2 , and five of its major tributaries. 

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• New Plymouth Catchments Stormwater Management Plan 

New Plymouth District Council, 2001-2002 

Project Manager and Senior Hydrologist/Hydraulic Engineer 

Responsible for detailed stormwater study and modelling of the Waimea, Huatoki and Mangaotuku Stream 

catchments in New Plymouth District, with a focus on the effectiveness of flood detention storage, both 

existing and potential, on the performance of the trunk stormwater drainage systems. 

• Wairoa Canal Development 

Synergine Operations Ltd, 2003 


Review of flood flow estimates for the lower Wairoa River (near Clevedon) and estimation of the design 

flood level for a residential canal development in a tidal reach of the river, including an assessment of the 

hydraulic effects of the development on the floodplain. 

• Lakes Wakatipu and Wanaka Design Wave Height Assessment 

Otago Regional Council, 2007-2008 


Assessment of wind conditions during elevated lake levels for developing a joint statistical probability 

distribution. The analysis enables the wave contribution to extreme water levels in Lakes Wanaka and 

Wakatipu to be determined. 

• Infrastructure Auckland Funding Applications 

Auckland City Council, 2003-2004 


Assisted in the preparation of funding applications on behalf of Auckland City and Metrowater for 

stormwater capital works, including treatment, system upgrading and sewer separation, for Pt Chevalier, 

Motions Creek, Upland and Orakei sub-catchments with a combined value of $130 million. Involved costbenefit 

analysis, including economic, environmental and social parameters, based on a 20-year timeframe. 

• Bowden Road Gross Pollutant Trap 

Auckland City Council, 2002-2003 & 2006 

Senior Engineer / Hydrologist 

Conceptual design of a gross pollutant trap on the Bowden Road stream (Mt Wellington, Auckland) for 

removal of trash and sediment from the streamflow before discharge to the coastal marine area. Options 

investigated included an innovative vortex tube device in addition to a conventional basin design. 

Subsequently involved in technical advisory role during detailed design and construction. 

• Kuala Lumpur International Airport Flood Studies 

HSS Integrated 


Conducted flood studies and conceptual drainage studies for the proposed new international airport in 

Sepang, Malaysia. Involved detailed audit of Sungai Langat water level and stage-discharge rating data 

obtained from JPS (TIDEDA data), and rainfall-runoff modelling to derive design flood hydrographs 

allowing for different levels of future urban development. 

• Lower Tongariro River Flood & Erosion Hazard Management Plan 

Environment Waikato 


Responsible for hydraulic modelling and regime analysis of the Lower Tongariro River for a 

comprehensive flood and erosion hazard management plan for the lower river including Turangi township, 

including design of rock revetments. 

• Otaki Flood Detention Dam Study 

Wellington Regional Council 

Senior Engineer and Hydrologist 

Pre-feasibility evaluation of several large flood detention dam options (25 m to 50 m high) in the Otaki 

area near Wellington, including costings. The brief included assessment of a 60 m high multi-purpose 

hydro-flood control dam option of the Otaki River. 

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• Stebbing's Valley Flood Detention Dam 

Wellington Regional and City Councils, 1991-1992 

SeniorHydrologist / Hydraulics Engineer 

Design flood estimation and routing, and detailed hydraulic design for the 20m high flood detention dam in 

Stebbing's Valley (constructed in 1992). 

• Limeburners Creek and Waitaua Stream Catchment Management Plans 

Whangarei District Council 


Managed the catchment drainage and stormwater quality management planning studies in the Limeburners 

Creek and Waitaua Stream catchments in the Whangarei District. 

• Lagoons Resort (now Clearwater Resort) Flood Hazard Study 

Boffa Miskell 


Responsible for flood hazard analysis, risk assessment, hydraulic floodplain modelling and providing 

technical support for plan change and consent hearings for a golf course resort development adjacent to the 

Waimakariri River floodplain, Christchurch. 

• Maitai River Waterway Upgrade 

Nelson City Council 

Project Manager and Senior Hydraulics Engineer 

Responsible for hydraulic and hydrological studies for the Maitai River waterway upgrading investigation. 

Involved backwater modelling of 7 km of the lower Maitai River through numerous bridges and built-up 

areas of Nelson City, and evaluation of channel capacity improvement options. 

• Jacksons Creek Hydraulic Modelling Study 

Christchurch City Council 

Senior Hydraulics Engineer 

Responsible for the hydraulic modelling study of Jacksons Creek, which runs through urban Christchurch. 

The MIKE 11 UD model of the 4.5 km stream included 2 km of culverted sections and 13 overland flow 

paths. 

• Gisborne Real-Time Flood Forecasting System 

Gisborne District Council, 1992 


Developed an advanced flood forecasting system based on telemetered rainfall and river stage data for the 

Gisborne District Council. The real-time hydrological modelling system predicts timing and magnitude of 

flood peaks. 

• Waimoko Stream Catchment Management Plan 

Waitakere City Council 


Project managed the catchment stormwater management planning study of the Waimoko Stream, West 

Auckland for the Waitakere City Council. 

• Flat Bush Flood Detention Dam 

Manukau City Council 

Senior Hydrologist / Hydraulics Engineer 

Detailed hydraulic design and flood routing studies for the Flat Bush Road flood detention dam for the 

Manukau City Council. 

• Hutt River Flood Frequency 

Ministry For the Environment, 1989-1990 

Project Leader and Hydrologist 

Project Leader for a study of the potential impact of climate change on flood frequency in the Hutt River 

near Wellington, which flows through the highly developed Hutt Valley. 

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• Hutt River Floodplain Management Plan 

Wellington Regional Council, 1990 

Hydrologist 

Computer modelling and simulation of the Hutt River catchment using a physically-based model to derive 

design flood hydrographs for the Council’s floodplain management plan. 

Publications 

Mixing of Dense River Inflows to Lakes 

Research Report No. 88/6, Department of Civil Engineering; University of Canterbury, 1988(ISSN 0110–3326) 

Real Time Flood Forecasting in New Zealand with R.P. Ibbitt, R.A. Woods, D.G. Goring 

Hydraulic Engineering Proceedings, 1990 National Conference, HY Div/ASCE, 1990 

The Potential Effects of Climate Change on River Protection: Case Study on the Hutt River with R.S. Jordan, R.P. 

Ibbitt, Publ. No. 26 of the Hydrology Centre, DSIR, 1992 

Risk Cost Approach to Optimizing Multi-Reservoir Operation with M. Byrne and C. King 

Proceedings, Hydro 2001: Opportunities and Challenges, Riva del Garda, Italy, September 2001 

‘Sediment Never Sleeps’ with J.Duder 

Proceedings, Hydro 2001: Opportunities and Challenges, Riva del Garda, Italy, September 2001 

The Mt Dobson Coffee Tin Raingauge Proceedings, New Zealand Hydrological Society 2002 Conference, 

Christchurch, 2002 

Resolving Water Resource Over-Allocation: The Wai-iti Catchment Community Water Augmentation Initiative 

Proceedings, First International Conference on Hydrology and Water Resources in Asia Pacific Region, 

Kyoto, March 2003 

A Method for Generating Synthetic Rainfall Data Proceedings, New Zealand Hydrological Society 2004 

Conference, Queenstown, 2004 

Creating Fish Habitat: Mitigating the Impact of Long Culverts with D. Slaven, C. Mitchell, Proceedings 6 th 

International Symposium on Ecohydraulics, Christchurch, 2007 

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David Leong - Appendix 1 - Environment Canterbury

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