Rees-Dart Riv iver management: resilience and adaptation Rees-Dart - PowerPoint PPT Presentation

Rees-Dart Riv iver management: resilience and adaptation

Rees-Dart natu tural l hazards

Lake Flo La loodin ing Flooding of Lake Wakatipu 1957, 311.6 m (Hocken snapshop image)

Rees-Dart delt lta growth th

Looking towards Glenorchy from Kinloch, Wetland at Kinloch ca 1875 (Hocken Snapshop)

Google Earth imagery, 2018

Rees s - past management Full floodplain width Engineered channel narrow, outflanked easily

Incomplete set of groynes Proposed groyne ext xtensio ion

Dart erosion repair ir work Feb 2016 May 2018 Diversion of main channel away from TR bank

Feb 2016 May 2018 Photo: Geoffrey Thomson June 2018

B A Floodbank Road

DR_3 Road Bank Flood plain very similar elevation to river bed. All part of growing delta Riverbank erosion

ORC – pla lan for r next xt 3 years • Addressing im immedia iate erosion, safer roads Every • Repair of crit itic ical l flo loodbanks and groynes year • Responsive riv iver management as needs aris ise • Defin ine key iss issues for r lo longer r term rm pla lan ➢ Ba Bala lancin ing touri rism needs: je jet t boats, preserv rvin ing wetl tlands, , im improvin ing roadin ing and in infr frastructure ➢ Allowing room for the river, ‘soft’ management Years ➢ Ca Cannot protect again inst delt lta growth th ind indefi finit itely ly 2-3 ➢ Cli limate change: : proje jected in increasin ing rain infall ll on the divid ivide, flo lood heig ight and fr frequency ➢ What is ‘critical’ for local/district/regional rate base?

ORC – pla lan for r next xt 3 years • Addressing im immedia iate erosion, safer roads • Repair of crit itic ical l flo loodbanks and groynes Reduction • Responsive riv iver management as needs aris ise Readiness • Defin ine key iss issues for r lo longer r term rm pla lan Response ➢ Ba Bala lancin ing touri rism needs: je jet t boats, preserv rvin ing Recovery wetl tlands, , im improvin ing roadin ing and in infr frastructure ➢ Allowing room for the river, ‘soft’ management ➢ Ca Cannot protect again inst delt lta growth th ind indefi finit itely ly ➢ Cli limate change: : proje jected in increasin ing rain infall ll on the divid ivide, flo lood heig ight and fr frequency ➢ What is ‘critical’ for local/district/regional rate base?

ORC – pla lan for r next xt 3 years • Addressing im immedia iate erosion, safer roads • Repair of crit itic ical l flo loodbanks and groynes Reduction • Responsive riv iver management as needs aris ise Readiness • Defin ine key iss issues for r lo longer r term rm pla lan Response ➢ Ba Bala lancin ing touri rism needs: je jet t boats, preserv rvin ing Recovery wetl tlands, , im improvin ing roadin ing and in infr frastructure ➢ Allowing room for the river, ‘soft’ management ➢ Ca Cannot protect again inst delt lta growth th ind indefi finit itely ly ➢ Cli limate change: : proje jected in increasin ing rain infall ll on the divid ivide, flo lood heig ight and fr frequency ➢ What is ‘critical’ for local/district/regional rate base?

Example le of f optio tions for r Dart Riv iver r erosio sion (n (not t an actu tual l cost-benefi fit analy lysis is)

Extr xtra slid lides

Extr xtra slid lides