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Flows at the mouth of the Mary
By Lindsay Titmarsh - Tandora
November 20, 2007
Tandora, Mary River, Queensland
Lindsay Titmarsh
On December 16th of this year, my family will have lived beside the Mary River for 100 years. The family property, 'Tandora' is the last farm on the river and is situated beside the vast riverine estuary. In those 100 years we have watched the mighty river change dramatically. In my gradfather'
My ancestors watched with great interest the movement of migratory waders. The activity was partly beacuse of an interest in nature but was mostly die to the practice of using them as table birds. As most of the waders migrated to northern bredding grounds towards the onset of autumn, their return was eagerly anticipated. The modern waders of today still trek north, but can be assired of being admired as beautiful bords in nature, not in the cooking pot. All the residents of southern Queensland must strive to assure our tidal wetlands remain in a healthy condition to guarantee the survival of our very important migratory waders.
Apiarists come from far and wide to participate in the sometimes enormous honey flow of the River Mangrove, the ditrict's most populous variety. During a productive flow which occirs in October, it is possble for 2 or 3 thousand commercial beehives to be positioned at various points surrounding the river estuary. As it is possible for bees to fill a beehive with honey in one week, sometimes enorous quantities are produced. A good flow which is dependent on seasonal conditions could easily yield 80 to 100 tonnes of honey. Honey eaters if the flying variety greatly depend on a good honey crop which beneficially coincides with their breeding season in the spring. The spring of 2006 produced a massive crop of mangrove blossoms. In 2007 hardly a flower can be seen. If the River Mangrove does not receive a good 'fresh' in the river system in the early part of the year, it will not be programmed to flower later in that year - that was the case this year. My greatest concern is that if a large dam on the upper Mary prevents environmental flows, then the folowering ability of estuarine mangroves will be affected at this end of the river, to the detriment of nature. Envioronmental officers from Brisbane have visited Tandora on more then one occasion to inspect a grove of exceptionally large Grey Mangrove trees growing on a tidal flat. They estimated that one specimen with a diameter of 2.4 metres could be over a thousand years of age. These trees grew to otheir enormous size under natural conditions, should we jeopardise others from attaining the same stature by altering the balance of nature?
It is not only mangroves and birds which depend on environmental flows in rivers. In 1992, two floods occured three weeks apart in the Mary River. Two or three months later commercial fisherman in the river expeprienced one of the best prawning seasons on record. Some operators were netting 1.25 tonne of the crustaceans per night. The bountiful population assured food for fish and birds for the reminader of that year. Environmental flows also keep mud dwellers which migratory waders so depend on, in a healthy condition.
After a tidal barrage was constructed across the Mary River, 59.3km upstream in 1982, the stram has changed. Small flows which flushed accumulated sand from the estuary are no longer prevalent, resulting in a huge sand bar just inside the river mouth. If another large catchment is constructed on the upper Mary, future generations will class that action as one of the most environmentally destuctive decisions ever made in south-east Queensland.