David Leong - Appendix 1 - Environment Canterbury

TONKIN & TAYLOR LTD
Environmental and Engineering Consultants
• 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
Senior Hydrologist
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
Senior Hydrologist
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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David Leong