Waimea Community Dam (Lee Valley) - Tasman

Irrigation New Zealand Conference – Napier 7 – 10 April, 2014Murray King

Joseph ThomasWaimea Water Augmentation Committee

Lower Waimea River Drought (dry river)& Flood (1500 m3)

Background• The Waimea Plains is acutely water short - water rationing

7 out of the last 10 years.• Shortfall 22 – 70% (~600 – 1900 l/s) depending on what the

low flow requirements in the Waimea River are set at.• Committee (WWAC) brief

“To find a solution to acute water shortage on the Waimea Plains”

• Limited high value land• Diverse land use• Long irrigation history• Well understood water resource• A multifunction dam proposed

Reservoir locationReservoir location

The Proposed Scheme• Concrete faced rockfill dam (CFRD)• Size of reservoir 13.4 million m3 • Lake size 65.9 ha• Dam height 52 m• Construction time ~2 years• Est. cost @ 2009 (excl hydro) ~ $42 million**Cost likely higher when CCI and final design/peer work completed – also subject to final tender price

• Time to fill 1 -3 months • Irrigable area 5850 ha(eq.)• Tasman(now/future) 1400 ha (eq)• Future Regional 515 ha (eq)

Dam Centreline

Scheme Ownership Structure

• Scheme would be owned by water users (community-owned co-operative scheme)

• Operated on a cost recovery basis• Proportion of cost should be borne by

community as a whole to cover the environmental flows (incremental cost of building a larger scheme) – 30%

• Other costs shared between users on basis of water demand

Where are we• Regional Plan progressed since late 2012

Dam & No dam Option provided & Hearing completed late 2013

• Commissioners decision notified in early March 2014 – important benchmark re no dam restrictions – significant water cuts kick in 15/16 if no dam - cuts up to 50 % every year and more beyond this - EDA findings next slide

• Consent preparation underway – 95 % complete, prelodgement/lodgement of consent ~ April 2014

EDA - GDP Findings – Cost of No Augmentation

This equates to GDP of $800,000 per hectare over 25 years

Design

• Detailed design 85 % complete• Hold until consent notified and any relevant

submission evaluated• Complete detailed design and tender• Using rating mechanism require SCP and LTP

planned 2014/2015

Challenges

• Both Regional Plan and Consents – Statutory processes

• Consents – agreement on mitigation • Land acquisition• Timing SCP/LTP – Political• Funding vs. financing – sources/options/CII• Efficient tender and costing

Discussion Q & A