Looking for answers
By ALEX EASTON
AFTER 28 years Laura and Roger Child thought they had seen the worst floods that South Golden Beach could throw at them.
Since the couple moved to their South Golden Beach home in 1978 they have weathered the benchmark 1987 Mother's Day flood, as well as numerous smaller floods.
But the one that hit them on June 30 was something different.
Mr and Mrs Child said the flood topped 700mm at their home twice the height of the Mother's Day flood despite Byron Shire Council having built a levee during the 1990s between them and the Capricornia Canal.
The couple said they lost almost everything in the flood, from their children's old books to a vintage Morris utility Mr Child had spent about nine years restoring.
Mr and Mrs Child are now angry about their losses, and confused over how a flood that was supposed to have been prevented from happening again could have got worse.
The flood has revived a debate about development, and the causes of flooding in the Ocean Shores region.
In the balance is the welfare of 5000 residents, many of whom had water through their homes and just want the flooding stopped.
Byron Shire Council and the SES both admit the intensity and spread of flooding on June 30 caught them by surprise.
In response, the SES is now rewriting its guides on the way floods work in the Ocean Shores region and Billinudgel. Byron Shire Council, with the State Government, has launched an eight-week study into the floods that could lead to new flood mitigation work.
Byron Shire SES controller, Noel McAviney, said flooding across the area had gone about 200mm higher than the Mother's Day flood.
Byron Shire Council flood modelling, seen by The Northern Star, shows a one-in-100 year flood, such as Mother's Day, should have meant minor flooding at South Golden Beach around the Capricornia Canal while the comparatively new Fern Beach estate stayed dry.
In fact, the reverse happened. Floodwaters rose close to a metre east of the canal, while the levee held them back on the western side. Water, from Wooyung, or from the canal'sCONVENIENT MARINA: The New Brighton Trading Post convenience store during the June 30 floods. Owners continued trading as water rose around them with customers paddling and swimming in until the area was evacuated.
Picture courtesy New Brighton Trading Postnorthern end, flowed in rapids through the streets of Fern Beach.
Other flooding at South Golden Beach appeared to have come from a breach in the canal levee at Berrimbilla Court, while New Brighton and Ocean Shores were swamped with water that burst from Marshalls Creek.
One possible reason for the canal and the creek bursting so dramatically is that, with the Brunswick River already swollen and water from the Pocket flooding Billinudgel, the heavy rain that fell on the Ocean Shores region had nowhere else to go.
SES rainfall readings are vague, but show the rain overflowed from the Brunswick Heads rain gauge, which measures up to 427mm.
Long-term Ocean Shores resident, developer and real estate agent Jim Mangleson said another factor was the land bridge built across the canal at Kallaroo Circuit, which acted as a dam, stopping floodwaters flowing north into the natural flood storage area of the Billinudgel Nature Reserve.
Possibly even more critical was the sealing up over the years of natural flood outlets north of South Golden Beach, at Helen Street and at the mouth of Marshalls Creek.
Mr Mangleson cites council documents from 1976, seen by The Northern Star, approving a plan to block the flood outfall north of South Golden Beach, despite claims it could worsen floods in the area by up to 70mm.
At the mouth of the creek a rock wall, built to stop the Brunswick River silting up, was also acting as a dam, preventing water from getting out of the creek during a flood.
The wall, and a lack of dredging in the river, robbed both creek and river of the depth needed to take floodwater, and funnel-shaped rock walls at the mouth of the Brunswick reduced its ability to dump floodwater into the ocean, Mr Mangleson said.
A third outlet was rumoured to have been at Helen Street, South Golden Beach, which Mr Mangleson said was once a creek.
Even without Helen Street, Mr Mangleson said the Brunswick River and South Golden Beach outlets, working properly, would have been enough to prevent flooding.
However, Noel McAviney said what could let water out could also let it in, and the outlets could have made things worse.
Outlets could let the ocean in during king tides, leading to extensive saltwater flooding.
Combined with an existing flood, such a backflow could be disastrous.
Mr McAviney said he rejected a call from Byron Shire Council (initiated by Mr Mangleson's councillor wife Jan) to reopen the outlet north of South Golden Beach early in the June 30 floods for that reason.
Mr Mangleson rejected Mr McAviney's concerns, saying land behind the dunes could not be reached by tides because it was above sea level.
He also rejected suggestions that the raising and levelling of land for house blocks could have worsened the flood by removing natural waterways.
Alstonville-based Department of Infrastructure Planning and Natural Resources flood expert Toong Chin said housing development could have an overall impact on flooding.
However, he likened the impact to pieces of straw on a camel's back, saying it was impossible to point to a single development, and said the impact of housing, levees, land bridges and ocean outfalls may be moot, in regard to the June 30 floods.
Byron Shire Council asset management services director Brett Lee said such factors steadily became less relevant as floods grew bigger.
Mr Lee said the new flood study aimed to learn how frequently residents could expect to experience floods like those of June 30.
The study would influence how the council and the State Government looked at flood mitigation around Ocean Shores.
New flood mitigation work to come out of the study could include changes to the levee and drainage systems around the area.
But Mr Lee said if the flood turned out to be a rare event, such as a onein-500 year event, the council would have to look at whether the cost of new measures would be worth the potential benefit.
The study comes too late to comfort families such as the Childs. Mr Child was involved in the floodplain committee that led to the levee being built in the 1990s, and says he has little faith in the council's, or the Government's, ability to fix the problem.
The couple have decided they want to move out of South Golden Beach -? their house was on the market before the floods hit -? but are now wondering at their chances.
"I took the 'For Sale' sign in during the flood," Mr Child said.
"Once I saw people going up and down the street in boats, I just thought 'what's the point'?"