THE SES has revealed for the first time how unprepared it was for more than 100,000 megalitres of water to surge down the Mirrool Creek in March, causing severe flooding in Yenda and its surrounds.
In an effort to dispel rumours he knew a disaster was headed our way, SES Murrumbidgee region controller James McTavish took The Area News through the events leading up to the catastrophe.
On Monday, February 27, a week before the floodwaters hit Yenda, the SES was advised a significant rainfall band was passing through the south of the state.
The initial focus was on catchment areas to the north-east of the Murrumbidgee, but by Thursday it had shifted to the Murrumbidgee River.
“We were aware that there would be main river flooding along the Murrumbidgee Valley and that what was coming would exceed the 2010 flooding event,” Mr McTavish said.
“At that stage the threat looked to be much more significant down the river than in the upper Murrumbidgee catchment.
“We weren’t counting on rainfall in the catchment considerably exceeding predictions and, on top of that, we had a lack of ability to gain situational awareness in the Mirrool Creek.”
On Saturday, March 3, the worst of the rain hit southern NSW.
Just over 133mm fell on the MIA, flooding Yoogali and Hanwood.
Barellan and Ardlethan also took a soaking like never before.
Water levels in the upper catchment of Mirrool Creek and the Leeton catchment crept toward tipping point.
That night, the SES established an emergency operations centre (EOC) in Griffith.
“At that time, we still had a very significant lack of information on what was happening in the upper Mirrool Creek,” Mr McTavish said.
“We had anticipated some flash flooding and had dropped sandbags in the areas we thought would be affected in the previous days but we’d had no indication of the events around the Mirrool Creek and Leeton.”
On Sunday, March 4, the organisations at the EOC made the decision to force a breach of the canal at Roaches Regulator near Leeton to prevent excess water flowing into the already-straining Murrumbidgee River.
There had also been a proposal to breach the canal system near Yenda where the Mirrool Creek meets the main canal and the northern branch canal but EOC officials were concerned about potential impacts on Yoogali, parts of Griffith and Hanwood.
The bank of the northern branch canal collapsed on Monday night, resulting in the flooding of Yenda.
“This event exceeded our knowledge and exceeded everyone’s experience,” Mr McTavish said.
“Now we are starting a process of ascertaining the expense of the flood as well as gathering greater flood intelligence so we can look into how to respond better if a similar event ever happens again.”
The SES believes about 125,000 megalitres of water passed through Mirrool Creek throughout the flood event.