Why is Townsville so dry? BOM explains it's the topography

Why is Townsville so dry? BOM explains it's the topography

Why is Townsville so dry? BOM explains it's the topography

Updated 4 August 2017, 17:40 AEST

Despite being famed for its tropical lifestyle and climate, Townsville cannot seem to shake its "Brownsville" nickname.

But why is there so little rain in this coastal city?

According to the Bureau of Meteorology, it is just in the wrong place for rainfall.

Most onshore winds from the south-east bring the coastal showers, but they bypass Townsville because of the angle of the coast.

"A lot of it's to do with the orientation of the coast line," forecaster Rick Threlfall said.

"Around the Townsville area, the coast pretty much goes to from south-east to north-west.

"So a lot of the showers go right on by and skip past Townsville."

It rains about 91 days of the year in the beachside city, and has an average high temperature of about 29C.

It lacks high surrounding mountains that drive rainfall, like those bordering its northern cousin Cairns. 

"Around Townsville there's really not a lot of topography there," Mr Threlfall said.

"So you don't have the hills to really force the air up to produce the rainfall."

There has been back-to-back failed wet seasons in Townsville.

It relies on tropical systems or monsoon troughs coming down from the north.

"And unfortunately the last few years it's really missed out on those systems," Mr Threlfall said.

The majority of Townsville's rain typically falls during the tropical summer months, known as the wet season.

It depends on strong monsoonal troughs or rain from cyclones.

By this time of the year, the city would average about 900 millimetres of rain, but its so far only reached about 650mm.

The poor wet season and dry winter mean Townsville is again drought declared — the city's main water supply the Ross river dam is down to 20 per cent.

Level three water restrictions were put in place, with residents only allowed to hand-water gardens for two hours a day, two days a week.

Townsville Mayor Jenny Hill said they were trying to teach the community water conservation, to keep costs down.

"We haven't seen a lot of rain for the last three years," she said.

There is a the option for the council get water from the Burdekin dam, which it will do once its water supply drops to 15 per cent.

Cane farmers in the region are tallying up the costs of the dry season too. Irrigation costs have soared.

Phil Marano's family has been farming cane in the Home Hill area for 90 years.

Five years ago the average cost of irrigation was maybe 50 cents to a dollar a tonne, now it is more like $5 a tonne

Because of the rising costs growers are pulling back.

"It's getting to the stage where a lot of growers are not irrigating as much as they should and it hasn't been raining and crops are starting to suffer."

Whether its town or country, winter will remain typically dry and at this stage there is only average rain forecast for next summer.