Beat Salination
Australia contains significant quantities of salt in it's soils and ground-waters. It is naturally a very
salty place, and the salt mostly responsible for dryland salinity is common salt, sodium chloride.
The original source is mostly the ocean. Salt is carried inland by rainfall varying with distance
from the sea - from 150 kg/ha/annum near the coast down to about 10 kg/ha/annum further inland. Over
thousands of years the salt has accumulated, together with weathering of soil and other minerals.
When Europeans arrived the salt wasn't obvious because rainfall and saltfall were balanced by the water
table and outflow of rivers.
But land clearing for agriculture disrupted the water-salt balance, resulting in salinity problems that
are steadily worsening along with rising water tables. It is not a new problem - it was documented as early
as 1864 by W.E. Wood, a W.A. railway engineer working to manage fresh water resources for steam locomotives.
Pump the Salt Out
Trials have already been done on re-habilitation of salt affected lands by pumping the salty water out
and lowering the water table. And some of this work suggests that running the salty effluent into the
drainage system has less impact than previously feared.
Another option is to pond the salt and leave it there - after all, it has been there for thousands
of years already.
But it costs money to fuel the pumps - it produces greenhouse gas - the salty water is wasted - and
we are already short of agricultural water.
All these problems dis-appear with a solar powered desalinator. The sunlight (fuel) is free, it does
not produce any green house gas and some of the water can be recovered as fresh to re-use for
irrigation of the reclaimed lands.
Rev: 5th Mar 2008
©2008 eTail Central
