I have been away to places green. Unfortunately, reading between the lines last week it appears that while the residents have had level 4 water restrictions, am I correct in assuming that the Armidale council have been demonstrating how to be more efficient using less water by pouring the stuff onto the central parks?
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I hope it was a misprint but the recent article on trees in Central Park claimed the council was going to give them five mm per week. I believe the tree group measures our average evaporation at about 3.5 mm/day for the next couple of months and five mm/day over December and January. (Our low evaporation rates are the reason our water consumption is low, in western areas of NSW it is a minimum of 10 - 15 mm/day).
Using those figures we can develop a water budget that would look a bit like this; the first day there will be a deficient of 3.5 mm of moisture in the soil, the second day, 3.5 + 3.5 = 7.0 mm and so on until after seven days the soil moisture deficit should be 25.4 mm. That is the amount that should be applied. (A lot more than five mm per week).
If it rained, 19 mm, we add that to the budget and miss 19/3.5 = five days before watering again. When the plant was watered the budget would return to zero and start again.
While the measurement of evaporation is taken from a bare water surface, other factors such as hot dry winds may increase it and cooler conditions reduce it.
The problem with keeping very old trees alive is stress.
Trees have to pump vast quantities of water and nutrients through the roots, stems and leaves to live.
As their water transport system breaks down they become highly susceptible to disease and insect attack. I am not quite sure why but frost seems to kill more trees in drought than at other times, I guess it is because, during times of moisture stress, they cannot pump enough water through their system to keep it from freezing.
Although not written in stone, trees, generally, have a root system about twice the height of the tree. I would have thought, if the trees were valuable then a drip watering system would have been installed and clean water pumped through it so only the root zone received water.
I installed a drip watering system with a filter to remove residue, using the clothes washing water to keep my fruit trees alive. It could be installed under mulch.
That brings me to mulch. It is used to reduce the temperature of the soil and evaporation losses from the soil surface. If it is applied on top of dry soil it will absorb all the moisture meant for the trees.
I believe councils must have sacked all their health inspectors because I am not sure of the health and safety applied to the recommendation inviting residents to use their scabies, pox and plague ridden shower water on top of the mulch to save trees in Central Park.
I think pouring water onto the mulch will only encourage an environment for plant diseases and fungi to attack the trees.
I can only guess that council are planning to use water from the Giro dam opposite the new age garbage tip where about 80 megalitres are stored. It appears that there is only one councillor left on council, strange that during the most serious water crisis this century we do not hear from any others.
Are they dead?
I can only imagine that cardboard cutouts are placed on the chairs so there is something to talk at. I might cover, the truth doesn't hurt us, next time.
Philip Gardner
Armidale
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