The options, from building levees to dredging the Hawkesbury-Nepean River or releasing water ahead of big rain events, were detailed in submissions developed in 2014 and 2015 and provided to cabinet, according to internal documents.
The fire covered nearly 85,000ha – just over half the island – and 30 different water bombing aircraft dropped more than 13 million litres of water on the fire.
Thirty-eight recommendations were tabled by the Queensland government in its review of the bushfire that razed 87,000 hectares of the World Heritage-listed island.