GNS Science geologist Sally Dellow said the severe rain - up to 100mm of rain an hour fell over parts of Roxburgh on November 26 and debris closed State Highway 8 on both sides of Roxburgh for several days - had tipped the thresholds for debris flows from four creeks in the Roxburgh region.
She said such incidents were ''going to happen again, that's a certainty'', but there were various mitigation options, including physical works such as building bigger bridges and culverts, and developing warning systems.
About 80 people attended the ''ORC Roxburgh Debris Flow: Community Information Session'', which also included presentations from Otago Regional Council (ORC) and NZ Transport Agency (NZTA) staff.
Meeting chairwoman and ORC Dunstan councillor Dr Ella Lawton said a joint agency approach between the ORC, NZTA and Central Otago District Council was the best way to decide mitigation measures and seek government funding towards any resulting projects.
Some of those at the meeting said it was Teviot Valley residents who had shown leadership and dealt with the emergency the rain caused, and Dr Lawton agreed local knowledge and responses were paramount.
ORC Central Otago emergency management officer Matt Alley showed excerpts of a draft Teviot Valley Community Response Plan at the meeting, and said it was one of several being done around Central Otago.
The draft plan would be distributed to everyone in the Teviot Valley in about a month, and be followed by periods of public consultation.
Teviot Valley residents are also being asked by the ORC for their feedback on mitigation options for debris flows.
Submissions can be made until June 7.
