RangitikiTarawera Rivers Scheme Rangitiki Drainage Scheme Scheme Assets

Rangitāiki-Tarawera Rivers Scheme & Rangitāiki Drainage Scheme

Scheme Assets Stopbanks Canal Systems Drains 3 • Floodgates • Pump Stations • Riverbank Protection

Rangitāiki Tarawera Rivers Scheme Assets 60, 000 50, 000 40, 000 30, 000 20, 000 Asset Group Structures Pump Stations - Stopbank 10, 000 Erosion Protection Replacement Cost ($000) Replacement Cost $77. 3 m (1 July 2014)

Community Outcomes

Typical Scheme Operational Activities Drain Maintenance – Weed Cutter Boat – Digger desilting/weed clearing – Aquatic weed spraying – Grass carp Culvert Replacements Floodgate Maintenance 7 Bank Erosion Repairs Pump Station O & M River Maintenance – Willow layering/removal – Planting – Flood damage repairs Stopbank Renewals

Significant Issues 1. 2. 3. 4. 5. 6. 7. Climate change Residual risk to community Affordability Events greater than design Levels of service Population growth/decline Geotechnical challenges

Environmental Considerations Environmental Code of Practice Regional Plans Permitted Activities with conditions Resource Consents Weekly Notifications Retrofitting fish passages Promote drainage and flood protection works that minimise adverse effects 9

Implications of Climate Change - More frequent & intense rain events - & Sea level rise. - Combined with - Perched rivers Land levels already low-lying [minus 1. 5 m. RL at lowest] Land shrinkage [already 6, 000 ha rely on pumping]

Geotechnical Issues - Soil conditions very poor Historic seismic events Perched rivers Challenging to reinstate 100 year standard Carried out huge amount of works but always risk of failures 11

Affordability/Debt 30, 000 Forecast Loan Balances ($) 25, 000 20, 000 15, 000 10, 000 5, 000 0 2015 2025 2035 2045 2055 Year 12 2065

Rangitāiki Floodway Project - Major flood event in 2004 - Main river channel lacks capacity - Floodway is key to getting 100 year protection reinstated - Capital works underway but met with many challenges 13

Rangitāiki Floodway Stage 2 b

Other Operational Initiatives

Example – Whitebait spawning sites when undertaking erosion protection works 19

Tidal Flushing

Tidal Flushing – Fish Friendly Floodgates

Willow tree maintenance

Toi with willow Establishing

Working with Partners Variation in restoration planting Use mānuka - possible use for honey, mānuka oil Mechanical spade - efficiency

Giant willow aphid