Wednesday 2 September 2009

Moratorium on development in the Barron River and Thomatis Delta

Ross Parisi is well-qualified to debate the incremental development in the Barron River and Thomatis Creek Delta: he's owned and farmed land their for many years. He's seen local river systems change at the will of nature, and witness the series of massive sand and sediment movement from the Tablelands to the delta during the floods of the late 70's.

Parisi doesn't call for a moratorium on development in the Barron Delta lightly, as some farmers on the Western side of the Captain Cook Highway from Machans to Yorkeys want to flog off their land to whoever will take it.

There are three significant sand mine extraction operations on the delta at Holloways, Caravonica and Yorkeys Knob. Council is currently being asked to consider extension of the Caravonica site. Along with Paul Freebody's water adventure park, these are both in the middle of enormous river systems, that are past their 30 year anniversary.

Ross Parisi, a former Mulgrave Councillor, sugar cane and watermelon farmer, knows the land and says the delta belongs to the river, and cannot be used at the will of development that will displace water and devastate beach side communities.

Geographically and historically deltas are the domain of river systems.

The Barron River / Thomatis Creek Delta is no exception. Councils that allow incremental development in river deltas without proper hydraulic modelling, do so at their peril.

Somewhere on the shelves of a Government Department, I assume the Natural Resources Department, one will find The Barron River Delta Investigation Report 1979.

This substantial $600,000 investigation was an inter-departmental Government study into the various behavioural aspects of the Barron River and Thomatis Creek. The investigation represented Part one, the gathering of information. Part Two, the construction of a physical model, did not proceed due to the lack of funding. The Mulgrave Shire Council in 1979 adopted the findings of the Investigation. Today, I am unsure if the Report’s findings are factored in when considering development applications.

The modern Barron River / Thomatis Creek Delta is some 6,000 years old. In places bedrock is some 100 metres below the existing ground level. Therefore, approximately 100 metres of alluvial deposits have raised the delta to the present level. This accretion process occurs with every flood.

The Barron River over that period has altered its water course, at least six to eight times. This process is ongoing and it is only a matter of time before the river will discharge at a different location on the Marlin Coast.

Thomatis Creek is about to change it's course again, as it eats away at its embankments on the Barron / Thomatis delta.
(see left of photo: September 1, 2009)

The furthest south it has discharged is southeast of the Airport at Ellie Point. Approximately two million metres of sand was deposited at this non active mouth. This mouth functioned until 1939 when during a flood it relocated further north to where it is today.

The furthest north is located between Earl Hill and Reed Road - Blue Water canal development. To the west, its furthest point is immediately behind the Caravonica School and crosses the Highway at Avondale Creek. The Western Arterial Road is constructed on a natural levee bank. The Lake Placid Caravan Park is situated in an old Barron River bed. Cattana Wetlands is a remnant feature of this system.

It is interesting to note that Thomatis Creek did not exist prior to 1932. The Captain Cook Highway at that time did not have a bridge crossing. It was a tidal channel with no connection to the Barron River. However, at some point in the distant past, it most likely would have been an active mouth.

The massive Barron Flood of January 1979

If no remedial action to restrict the increasing water flow is taken, within a short matter of geographical time Thomatis Creek will be the major outlet catering for the bulk of Barron River water flow.

Significant floods were recorded in 1967, February and March 1977, January 1979, where millions of cubic meters of sand was displaced and river systems were changed. Just two years ago, the river rose so high, it lapped over the road at the Barron River bridge.

The Investigation showed that the Barron River is silting.

This activity is normal behaviour for an older river system. As the riverbed height rises an increasing water flow volume finds its way down Thomatis Creek. This is compounded by the fact that it has a steeper bed gradient and is a shorter route to the ocean. The increasing erosion to the banks of Thomatis Creek, visible during an upstream fishing trip is indicative of an increasing water volume flow.

Barr Creek, situated at the entrance to Holloways Beach, may well one day again become a year-round active creek mouth as it now does when in flood.

There is evidence of general erosion along the creek, with one hectare of cane land being eroded during the last 30 years in one particular section, on a bend 300 metres upstream from the Holloways Beach Boat Ramp. Once the levee bank erodes completely, Thomatis Creek will have a twin mouth. Approximately 30 metres is yet to erode before Barr Creek becomes another mouth of Thomatis Creek.

If no intervening work is done to abate this erosion, dire consequences may well follow. There is a possibility following another major flood that Holloways Beach residents may wake up one morning to find they now live on an island.

Conclusion and recommendations

It is obvious that the Barron River / Thomatis Creek Delta is forever changing. Therefore, it is imperative Cairns Regional Council restrict the type and magnitude of development.

Any additional filling for building purposes will have an incremental deleterious effect on the flooding of Lake Placid, Caravonica, Machans Beach, Holloways Beach, Yorkeys Knob and Blue Water.

The proposed Adventure Water Park is located within an old Barron River channel. The highway culverts opposite the proposed development are indicative of a channel. When the delta is in flood this section has extremely fast moving water flows. The Cairns Regional Council should defer consideration of this development until a Council-commissioned hydraulic study is conducted and the proposed development can be tested through a computer flood model.

The active sand mines situated alongside the Barron River at Caravonica and Holloways Beach need to be closely monitored as to the effects on the hydraulics of the Barron River and Thomatis Creek. The constructed levee banks that protect the sand mines from flood waters have the effect of diverting the water flow from its natural water course.

Furthermore, it is my considered view that an immediate moratorium be put in place on further developmental applications.

A hydraulic study with a computer flood model, commissioned by Cairns Regional Council needs to be conducted so that any proposed development can be measured against the effect on downstream/ upstream flooding and the behaviour of the Barron River and Thomatis Creek Delta.

Until this is done, we need a moratorium on development in the Barron River and Thomatis Delta.


Edge Hill Tony said...

According to the plans, Paul Freebody is proposing a flood wall around his entire project. This will raise the water level in the rest of the flooded areas, including the access roads into Yorkey's, Holloways, and Machans. This is an enormously stupid idea - if allowed for every project, the walls would need to be higher and higher.

This ain't Holland, Freebody. Stick your project somewhere appropriate. And stop harassing the public for speaking out!

Unknown said...

if this was Holland,we'd have wind-mills and
"coffee shops". No one would ever leave....

nocturnal congress said...

The Barron River Delta Investigation Report can probably be obtained through a Member of Parliament's office or through the James Cook University.
Let's not all forget that the original Smithfield was swept away after the 1890 cyclone (?) when the Barron River changed course.

KitchenSlut said...

I was told there was also a rezoning, or change of material use, notice posted recently for low lying caneland along the Lower Freshwater Rd between Freshie and Kamerunga.

Dallas said...

At last, some non-partisan, apolitical and credible information is introduced. If you want to go a step beyond the delta and understand sediment fate and consequent beach erosion, have a read of the Mulgrave Shire Northern Beaches report prepared by the Beach Protection Authority in 1982. It is heavy with science but at the start and finish has lots of layman’s explanations of what has happened and why and quite accurately predicts what will happen (between 1982 and the present). This fascinating book is in the Smithfield Council library and probably JCU as well.

Makes the Cairns Council engineers look like boys holding their fingers in dykes. (!?!?) You gotta wonder what will happen to the acres and acres of waste now buried on the delta and the resulting pollution of the groundwater as well as the acres of open pits that are full of this polluted water. Where will it all go when the river changes course again as it inevitably will. The notion of Thomatis Ck becoming the main river channel aint as far fetched as it sounds, more a case of not if but when.

North Cairns, Barry said...

Since the state government is mandating local councils to stop building on the coastline, will the new hospital remodel be required to put the building up on "stilts" like every other Queenslander?

A hospital on the oceanfront, under the flight path to an airport. What a joke. I hope Bligh knows that eventually this decision will have her with blood on her hands.

Ross Parisi said...

It is to be hoped that the Cairns Regional Councillors and Town Planning staff, who prepare the recommendations for Councillors to consider, are fully cognisant of the effects of the increased flooding height at Caravonica, Smithfield, Trinity Beach, Blue Water, Yorkeys Knob, Holloways Beach, Machans Beach, Kamerunga, Stratford and Freshwater, with every development approved.

At this point in time there are three sand mines extracting. Two of these recently brought adjoining cane farms for expansion purposes.

The Caravonica sand mine has a current application before Council for the extension of the extracting area by approx 100 hectares. In total area this sand mine is approaching 250 hectares.

The sum total of the three mines, if the current application is approved will be approaching 400 hectares in area. This represents approx 10% of the Delta flood plain.

Levee banks will most likely be a condition of approval as a means of deflecting the flood water and also stopping the Barron River from changing course yet again

A 10% displacement of flood water will increase the flooding in all of the above mentioned townships by at least 10%.

The Cairns Region has not experienced a 1 / 50 year flood since 1979.

The above mines were not in existence prior to 1979 and therefore their flooding effects were not consider in the Barron River Delta Report.

While the Cairns development industry needs the sand raw material, I believe the Council ought to consider the closing down of these sand mines.

There are ample sand reserves in the Mareeba region, some of which are been used to supply the Cairns concrete batching plants and the construction of cement building blocks.

A responsible Council would instigate an overall report on the suitability of the Delta sand mines continuing.

Considering the Delta consists mainly of sand deposits, there does not seem to be an end in sight until the whole of the Delta is extracted of its sand resource and becomes a man made mega lagoon.

Is that the legacy we want to leave our children?

nocturnal congress said...

All the more URGENT reasoning for a moratorium on development in the Barron and Thomatis deltas. It will be interesting to see if the CRC agrees or simply puts its head in the sand and crosses its fingers and Councillors all pray they are out of office when disaster strikes. "It didn't happen on MY watch!"

Drainage Engineer said...

Have any of you "experts" looked carefully at the overflow route?

The Barron River overtopped in the vicinity of Lake Placid.

Council has recently spent big bucks flood proofing the low areas at Caravonica.

The Barron will not cause the flooding devastation that occurred in 1977because of these works.

The food mitigation works recently completed were planned to prevent a similar catastrophe.

Rate payer dollars well spent.

Ross Parisi said...

Drainage Engineer, where did you do your practical work? May I respectful suggest your theory is some what flawed as well

Sadly, the recently Council constructed levee bank will not flood proof the Caravonica township. All it will do is provide a false sense of security.

In a flood of the magnitude of 1967, 1974, 1977 and 1979 the Caravonica township will flood. Floods of a lesser intensity are not a treat to Caravonica.

The recently constructed levee bank will prove useless as the Barron River flood waters will back up Avondale Creek and then along the former river channel behind the Caravonica school.

Is the Figtree Drive Road built above a 1 in 50 year flood level?

Do the culverts under Figtree Drive have floodgates?

Does the Flood mitigation work include the installation of water pumps to remove the dammed local flood waters if the floodgates are installed and the Barron River flood waters back up?

If not the rate payers dollars were not well spent!!

Quien Sabe said...

Flood mitigation...?

If we have we not yet learned that if Mother Nature decides to chastise "humankind" for it's arrogance and follies, then I guess we never will.

New Orleans learnt that lesson to their eternal cost.

To quote an old song, "it's a lesson too late for the learning"...

Delta Pioneer said...

I hope the CRC will take note of what has been said in this lead article. Nature is ever so much more powerful than humankind. If we meddle with nature's playground we are courting disaster.
I have lived in the delta for many years and have seen the Baron River with all its fury play merry hell with man made objects.
Do we want a repetition of New Orleans right here on our doorstep?

Northern Beaches Warrior said...

Sounds like the same CRC Drainage Engineer who told a group of residents who back on the Clifton Cottages development, that they would all have to build brick walls around their properties.

Why you ask?

Because Council failed to make the owner of this development adhere to IPA legislation and have a legal exit point for all storm water, so there are no external drains etc. All water runs off the roof, down downpipes and enters pits on the property. When these pits overflow, the stormwater then runs off Clifton Cottages site and into the backyards of its neighbours flooding their garages, yards and houses. This has been an ongoing problem now for 2 years.

Of course the developer built up his site before construction, so that water is now running downhill at a rate of knots.

Easy peasy for Council. Shift all responsibility and blame from them to residents, both the adjacent owners and the new owners of the units. Similar situation to the Clifton Views site (different developer). No accountability from Council when they stuff up and fail to do their jobs professionally and residents have to cop massive flooding events that never occurred pre development on these sites.

This drainage engineer's credibility is zero and his lack of competence and professionalism is in abundance!