Reed beds
I have spoken before about the uses of reed beds and wetlands for improving water quality. A well constructed wetland, like the one in this photo, removes over 90% of the nutrients and 90% of the bacteria from the water as well as allowing for the natural removal of over 90% of sediments from the water before it is discharged in the rivers and sea.
However when I was reading Peter Andrews wonderful book “Back from the Brink” I learned of yet another important natural role for reeds in our river systems. This one should have been obvious. Peter points out that reeds in a river slow the water and spread it out over the flood plain so that the flood plain water table is recharged naturally and very importantly, the river bed does not erode down.
In our greed to have more flood free land we have build on these valuable floodplains and removed to reeds to prevent flooding and our rivers have deepened as they rush the water fast to the sea preventing the aquifer recharge that we so desperately need.
In the cities we have taken this a step further and concreted the creek and river systems so that they get rid of the storm water faster and leave us moaning about why we are facing water shortages and severe restrictions.
Does this seem to be a major form of insanity of what? We need the down-to-earth common sense of people like Peter Andrews to help us find natural ways to restore balance. Instead we have governments still turning to their engineering solutions like concreted rivers and making things worse. Perhaps all engineers should be forced to do a unit of environmental management that is NOT taught by engineering lecturers.
In Adelaide where I live, urban planning regulations force most of our rainwater directly into the streets and the concreted creeks, then pumps salt laden water from the Murray River to supply 40% of Adelaide ’s total supply. A report by Mr Andrew Speers, leader of CSIRO’s Urban Water Program. states that Adelaide could be independent of the Murray water. He said that the Adelaide Hills could provide water for the city’s needs all year round with some to spare. “There is potential to make better use of 168 billion litres per year of rainwater and wastewater currently being lost down city drains and in the sewage system”.
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