Jim Salinger: Lessons for all in Oz's flood readiness

The Nireaha Hall surrounded by flood Waters, Eketahuna. Photo / APN

Opinion

As I watch from my temporary summer residence in Hobart, Tasmania, the somewhat unprecedented rains that are deluging parts of Australia raise some pertinent lessons on the flood warning system in New Zealand.

The extremely wet December in eastern Australia primed the area for the record floods that were to follow this month.

The Bureau of Meteorology figures showed that eastern Australia (the states of Queensland, New South Wales, Victoria and Tasmania) had its wettest December on record, with an average area total of 167mm (132 per cent above normal). The soil could not take any more moisture and the further heavy rains became the floodwaters we saw in the news coverage.

What caused Brisbane to flood were the heavy falls to the north and west between January 10 to 12 with totals for the three days exceeding 200mm. In Toowoomba more than 100mm fell in less than an hour.

Further south in Victoria heavy rainfall and flash flooding occurred between January 10 and 15, with more than 100mm of rain across two thirds of the state.

Bureau of Meteorology figures showed many weather stations in Victoria have now broken their all-time January records in more than 100 years of observation: 259mm fell on Dunolly (the previous record was 123mm), and 282mm of rain fell in one day at Falmouth in the northeast of Tasmania - the highest ever recorded one day total for any gauge in the state for January.

But while the rains were extraordinary, the Australians were well prepared. They have an excellent integrated flood warning system. Precipitation forecasts by the Bureau of Meteorology are used by their hydrologists to monitor river levels and issue hydrological forecasts giving people accurate predictions of the flood peaks for each river catchment, large or small.

The system has worked extremely well and allowed emergency managers to minimise loss of life and prepare communities.

At the same time the public have access to websites where the weather information and images from rainfall radar are updated every 15 minutes. This empowers people to make their own assessments of the danger to their lives and property. In New Zealand there is no such integrated system. MetService produces heavy rainfall warnings which are issued to the media for broadcast and to regional councils. It is the responsibility of regional councils to assess the risk of flooding from rivers in their catchment areas.

And each regional council makes these assessments in different ways. The flood prediction models and expert hydrologists able to make the flood forecasts sit in the National Institute of Water and Atmospheric Research (Niwa).

France, a country prone to flash floods, used to have a similarly confused flood forecasting system. There were 52 autonomous flood forecasting units - one in each French department (area of local government) before 2002. Reforms were launched together with a national flood vigilance plan over the period 2002 to 2006 when a national flood forecasting service was launched. This service takes the precipitation forecasts from Meteo-France, the French Meteorological Service, and produces intensity rain-flood risk maps daily. These cover 90 per cent of the people living in the areas that are likely to be flooded. Britain is now considering implementing such a system.

The lesson from Australia is that New Zealand (where in the 19th century drownings from rapidly rising rivers were so common that they were dubbed by the Pakeha as "the New Zealand death") needs to move to a flood warning service that is worthy of a sophisticated 21st century country.

The MetService is at present searching for a new chief executive which makes an ideal opportunity for this to happen.

In the original Crown Research Institute plan of 1992, the MetService and Niwa were supposed to be one. This would have resulted in the integrated system we require. Although there is an agreement that the two will work together in a national emergency, by the time a disaster is declared, it will be too late.

One of the main raisons d'etre for the existence of meteorological and hydrological services is to provide warning services to civil society to prevent loss of life and property.

Many countries have national meteorological and hydrological services in one organisation. It is now timely to introduce such a seamless system for the benefit of all New Zealanders.