Winter Walking in the Barron River Delta (Cover Article 12 August 2005)

Submitted by Webmaster on Mon, 17/10/2005 - 18:57

In winter (July) the lowest low tides of the year allow people to walk for kilometres across the bed of the sea. One of my favourite places for low tide walking is the great sandy expanse around the mouth of the Barron River. For me it is a place to enjoy wide open scenery and to play with my family – mostly just walking around and seeing what we can find or catch. The Barron River mouth is a land shaped by nature that lies minutes from the commercial madness of Cairns.In 1927, the mouth of the Barron River pointed towards Cairns and was about 2 km south of its present position. However someone decided that it would be nice to have a house with the river on one side and the beach on the other and they cleared some vegetation. Of course a flood came and was able to erode the sandy soil where it had been disturbed and the river broke through the beach ridge, establishing a new river mouth. A little further north someone else cleared a field between the end of Richters Creek, which flows into the Barron River and the start of Tomatis Creek which flows into the sea. During a flood, Richters Creek flowed backwards and the waters crossed the field to Thomatis Creek and soon erosion of the field had permanently joined the two creeks. These two events started the greatest coastal erosion event the far north has ever known and resulted in the rock walls of Machans and more recently Holloways Beach. The development of large sand flats at the mouth of the Barron River are part of this recovery process.When the Thomatis Creek connected the Barron River and the sea, much of the river sand flowed down the new channel which is 7 km shorter than the alternative route to the sea via the Barron River. The sand from Thomatis Creek is responsible for the healthy state of Yorkeys Knob’s beach today. Just after the creek broke through, there were no sandbars near the new river mouths to catch the sand and much of the sand was carried out into deep water and lost from the beach. The result was that Yorkies nearly disappeared and I have seen 1950’s photos showing the bitumen of the esplanade being undermined. Today the beach has prograded out by more than 50 m. At the time the rockwall at the northern end of the beach was constructed to try to keep the remaining sand on the beach at Yorkies by blocking the usual northward drift of sand.Machans Beach fared somewhat worse. It went from having a broad beach to none at all. Holloways Beach once had a street along the top of the beach that disappeared into the sea and apparently, this is why the houses at Holloways are so close to the sea! The sand that replenished the beach was lost to sand dredging (now stopped), or flowed down Thomatis Creek or flowed into deep water at the new Barron mouth. It has taken nearly 80 years for a new sand flat to build up in the relatively deep waters. Sand from the sand flats is now being carried slowly back to shore by waves and by wind and perhaps, Machans Beach rockwall will slowly be covered by a rebuilding sandy beach. The story is important because the sandflats are a land of change and even during my life time, many of its features have moved by hundreds of metres and millions of dollars have been or are being spent assisting some changes and resisting others.More recently, the sand flats on the southern side of the Barron River were quarried for sand to provide fill for the international airport. A paper by Fisheries reveals that even after 17 years, the sea grass beds have not recovered in the impacted area. My observations suggest that seagrasses (Zostera) can recover if conditions are right as there are some vigorous patches located where the tip of Redden Island used to be before the last flood washed away another 50 m of land. I wonder how this area will change in the future?Photos: Aerial photo of Barron River Mouth; favourite fishing spot at Ellie Point on the southern side of the river mouth; rippling sand; pelicans resting near shipping channel; shallow pools between sandbars; and a view from the southern end back to Cairns City Ed.

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