A significant body of research shows that extreme rainfall events are becoming more frequent and more intense as the climate changes.
These changing rainfall patterns are likely to result in more flash floods, while changes to large scale climate patterns around the world and increasing temperatures may lead to increased risks of drought. Both are worrying outcomes.
Droughts reduce agricultural productivity and can lead to more bushfires and higher livestock and wildlife mortality rates. Floods, meanwhile, pose direct hazards to people, and damage property and infrastructure.
Over the last decade, communities in almost every state have experienced severe droughts and flooding, with residents witnessing first hand the destruction and chaos that can ensue.
In order to be more prepared, and keep people safe, our cities and towns need upgraded infrastructure, designed to withstand these extreme events.
This is exactly what Dr Fiona Johnson from UNSW’s School of Civil and Environmental Engineering is helping to provide.
Johnson’s research is focused on developing a clear and strong understanding of patterns of rain events connected to flood and drought.
“The questions are around how these increasingly intense rain events are embedded in longer periods of drought and flooding,” she says.
“Are they more spaced out or closer together? At the moment, we don't have a good feel for this. The sorts of events we're looking at are quite infrequent so it is difficult to do statistical analyses of them because the data is noisy.”
Johnson, who previously worked at the Bureau of Meteorology, is analysing data so that frequency and intensity of rain events, over a period of several decades, can be reliably predicted. She’s also factoring in where the rain is falling – for instance, on saturated farmland, drought-affected scrub or concrete pavements of a city – and the environmental conditions accompanying the event.
“We're looking at statistical analyses of historical records,” Johnson says. “We are trying to diagnose the meteorological conditions that are conducive to extreme rainfall. Then we are trying to see how well they may or may not be represented in climate models.”
While the data is centred on Australia, Johnson says her method-based work can be applied anywhere in the world.
“Water managers and engineers in certain industries need these numbers to design infrastructure,” she says. “Good design benefits everyone. It means people can get to work without the roads being flooded.”
Her research is also vital for drought planning and water management.
“Water managers need to come up with plans that essentially look at the distribution of water between different users in different regions. To do that they need to reliably know how much water they will likely have to share around.”
“We can never drought-proof or flood-proof the nation. But we can provide great information to ensure optimal decisions are made around infrastructure design and policy.”