Mary, Mary quite contrary
THEY say it’s just a feeling in your bones.
Long time Mary River watchers keep a close eye on weather indicators and then couple that with a little bit of intuition as to when the river is likely to rise enough to spill into Mary Street and surrounds, inundating large areas with a major flood.
The last “big one” occurred on February 10, 1999, when the mighty Mary peaked at 21.95m; high enough to enter the lower level of The Gympie Times office.
Dubbed the “flood of the century”, it paled just a little when compared to the biggest flood ever recorded on February 2, 1893.
That monster peaked at 25.45 metres and The Gympie Times was there, reporting to its readers the extent of the damage.
You could say the 1890s were a wet decade, when on January 10, 1898, the river reached 22 metres.
In 1974, one flood followed fast on the back of another with the river peaking on January 26 at 17.65m and again on January 28 at 20.73m.
Rainfall records show that January 1990 received 165.7mm and was followed by a very wet February, which soaked the region with 478mm.
In the first five days of March 2010, Gympie has received nearly twice as much rain as it did in March 2009, notching up 118mm compared to 78.8mm for the whole of March last year.
With the weather bureau saying there is more rain to come, there is always a chance that another flood could occur.
The Mary River catchment covers an area of more than 7000 square kilometres, with its headwaters located in the high rainfall areas around Maleny and Mapleton.
Average annual rainfalls in the catchment range from around 2000mm in the headwaters to around 1200mm near Maryborough.
At Gympie most floods (nearly 80 per cent) have occurred between December and April. During this period, heavy rainfall in the headwaters areas is likely to cause moderate to major flooding in the Mary River at Gympie.
Floods at Maryborough are typically caused by heavy rainfalls over the upper catchment, but it is possible that heavy rainfalls in the catchment below Gympie can cause noticeable rises in the lower reaches of the river.