Environmental Engineering Reference
In-Depth Information
Table 6.2
Water use efficiency in Australian irrigated agriculture
Industry
$/ML return
Pasture, grains*
270
Dairy*
529
Rice
179
Cotton
420
Sugar
217
Fruit
1590
Grapes
1859
Vegetables
1817
* These two categories use 50% of irrigation water.
Source: Derived from data on water usage and economic returns
included in
Water Account Australia
(2004).
biota observed were a function of the chemical and physical environment
experienced by the organism over some particular period of time.
The National Land and Water Audit (2002) reported a biotic index for
many Australian rivers based on the observed communities of aquatic inver-
tebrates. These give a consistent and useful measure of the health of the river
in comparison to an unimpacted reference site.
Norris (2001) reported a snapshot of river health in the Murray-Darling,
based upon aquatic invertebrate populations that showed widespread
impacts on the river systems. Other biological measures of the degraded
condition of the Murray River include:
•
loss of red gums on floodplain below Euston
•
listing of Murray Cod as threatened
•
decline in native fish and explosion of populations of carp
•
cold water pollution extending up to 300 km downstream of major
storages
•
almost permanent algal blooms in the Lower Murray
•
closing of Murray mouth and Coorong.
Despite this growing body of evidence, there are still various interest
groups in denial about the health of the Murray-Darling river system. Some
upstream irrigators assert the river is in good condition, and there is no need
for them to change their irrigation practices. There are good local catches of
