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4613.0 - Australia's Environment: Issues and Trends, 2006  
Previous ISSUE Released at 11:30 AM (CANBERRA TIME) 10/11/2006   
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Contents >> Water trends >> Water quality

WATER QUALITY

MAINS/TOWN WATER AS MAIN SOURCE OF DRINKING WATER


Drinking water quality in Australia is high by world standards, considering that globally more than one billion people still do not have access to safe drinking water.

In Australia, 93% of households were connected to mains/town water in March 2004. Almost all households (98%) in capital cities were connected, compared with 85% of households outside of capital cities. This discrepancy was largest in Tasmania, where 96% of households in Hobart were connected to mains/town water, compared with 77% for the rest of the state.

In capital cities, 89% of households relied on mains/town water as their main source of drinking water while in regional areas this dropped to 67% of households. South Australians were least reliant on mains as their main source of water for drinking (60% in 2004) although this had increased significantly from 50% in 2001.

Over the same period, South Australia's reliance on rainwater tanks as the main source of drinking water decreased (from 33% in 2001 to 26% in 2004), as did their dependence on purchased bottled water (from 16% in 2001 down to 13% in 2004).

MAINS/TOWN WATER AS MAIN SOURCE OF DRINKING WATER, 2004
Graph: Mains/Town Water as Main Source of Drinking Water, 2004
Note: NT and ACT data refers to the whole territory.
Source: ABS, Environmental Issues: People’s Views and Practices, 2004 (cat. no. 4602.0).
PURCHASED BOTTLED WATER


On a national level, about one in five households (21%) purchased bottled water in 2004 compared to 16% in 2001. Nearly one in ten households (8%) had it as their main source of drinking water. In the ten year period from 1994 to 2004, the proportion of households that purchased bottled water increased from 3% to 21%.

PURCHASED BOTTLED WATER
Graph: Purchased bottled water
Source: ABS, Environmental Issues: People’s Views and Practices, 2004 (cat. no. 4602.0).
SATISFACTION WITH QUALITY OF TAP WATER FOR DRINKING


Generally, there has been a steady increase in the level of satisfaction with the quality of mains water for drinking across Australia, from 64% in 1994 to 70% in 2004. The level of satisfaction did vary between states and territories, however, with the Northern Territory (89%) and the Australian Capital Territory (87%) having the highest rates of satisfaction. At 52%, South Australia had the lowest levels of satisfaction.

Half of those who expressed dissatisfaction with the quality of drinking water nominated taste as the reason. Other common complaints included chorine, dirty water, odour, colour and microbial or algae contamination. Western Australian households registered the highest level of dissatisfaction (60%) with taste (excluding saltiness).

SATISFACTION WITH QUALITY OF TAP WATER FOR DRINKING
Graph: Satisfaction with quality of tap water for drinking
Source: ABS, Environmental Issues: People’s Views and Practices, 2004 (cat. no. 4602.0).
USE OF WATER FILTERS


The use of water filters in Australian households has increased since 2001, with more than one-quarter of households (26%) now using water filters in drinking water (up from 21% in 2001). This increase in the use of water filters was greatest in South Australia (from 23% in 2001 to 30% in 2004), and Western Australia (from 24% in 2001 up to 29% in 2004).

USE OF WATER FILTERS
Graph: Use of water filters
Source: ABS, Environmental Issues: People’s Views and Practices, 2004 (cat. no. 4602.0).
RAINWATER TANKS


Sixteen per cent of Australian households sourced water from a rainwater tank in 2004. About one in ten Australian households relied on rainwater tanks as their main source of drinking water. This increased to nearly one in four (24%) for households outside capital cities. For areas in South Australia outside Adelaide, this reliance on rainwater tanks increased to 66%. By contrast, only about one quarter (26%) of these households depended on mains/town water as their main source of drinking water.

RAINWATER TANKS AS MAIN SOURCE OF WATER FOR DRINKING, 2004
Graph: Rainwater Tanks as Main Source of Water for Drinking, 2004
Note: NT and ACT data refers to the whole territory.
Source: ABS, Environmental Issues: People’s Views and Practices, 2004 (cat. no. 4602.0).

Just over one-third (34%) of households without rainwater tanks had considered installing one. This was up from 25% in 2001. For those households which had considered installing a rainwater tank, cost was the main reason preventing this from occurring (41%). One in four households stated they had no time/hadn’t got around to it.

REASONS RAINWATER TANK NOT INSTALLED
Graph: Reasons rainwater tank not installed
Source: Environmental Issues: People’s Views and Practices, 2004 (cat. no. 4602.0).
RIVER WATER QUALITY


The table below shows commonly used indicators for assessing water quality in rivers. The Australian Water Resources Assessment 2000 (NLWRA, 2001) assessed about 30% of Australia’s 246 river basins. It identified major nutrient (mainly nitrogen and phosphorous) exceedences in 43 assessed basins (nearly two-thirds of those which could be assessed).

Salinity, the saltiness of the water, was a major water quality issue for 24 of the 74 assessed basins (32% of basins) in the NLWRA 2001. High levels of salinity occur in catchments where a large proportion of land has been cleared. Increased salinity in ground and surface water will worsen the irrigation salinity problem that many farmers already face. The table shows some of the environmental impacts of increasing salinity in freshwater systems including loss of diversity of aquatic life and vegetation.

Turbidity is the clarity or “dirtiness” of water and roughly equals the concentration of suspended solids in water. It was a major water quality issue in 41 of the 67 assessed basins.

Significant gaps in water quality monitoring preclude a comprehensive assessment of all of Australia’s river systems.


EXCEEDENCES OF WATER QUALITY GUIDELINES, 2000
Major
exceedences (a)
Significant
exceedences (b)
River basins
assessed
no.
no.
no.

Total nitrogen
19
19
50
Total phosphorus
40
20
75
Salinity (EC)(c)
24
18
74
Turbidity
41
10
67

Note: No assessments for Tasmania or NT or for less intensive land use areas.
(a) Major exceedences occupy greater than 33% of the basin area.
(b) Significant exceedences occupy greater than 5% but less than 33% of the basin area.
(c) EC = Electrical conductivity unit. It is used as a measure of water salinity.
Source: National Land and Water Resources Audit (NLWRA), 2001, Australian Water Resources Assessment 2000.

POTENTIAL IMPACTS FROM CHANGES IN WATER QUALITY

Water quality indicatorPotential impacts from changes
TurbidityIncreased water surface temperature due to changes in light penetration
Increased sedimentation can cause changes in breeding patterns of bottom gravel dwelling organisms
Suspended particles can cause suffocation in some fish
Adverse effects on fishing, aquaculture and tourism
Increased cost of treating affected water
SalinityIncreased physiological stress on organisms leading to population declines in native aquatic animals and growth inhibition of aquatic plants
Adverse effects on riverbank vegetation, bank erosion
Reduced suitability of river water for irrigation
Increased costs for treating drinking water
NutrientsExcess leads to excessive plant growth which chokes waterways
Increased nitrogen increases algal growth and 'nuisance plants'
Reduction in light penetration smothers habitats of bottom gravel dwelling animals
Decreased dissolved oxygen due to weed mat die off
Increased occurrence of blue-green algal blooms which can affect human health through contact or consumption

Source: National Land and Water Resources Audit (NLWRA) Australian Catchment, River and Estuary Assessment, 2002.

AQUATIC BIOTA INDEX (MACRO-INVERTEBRATES), by state and territory, 2000

Total length of reach (km) in each category and percentage of total in parentheses
Percentage of total length
with data
Reference
Significantly impaired
Severely impaired
Extremely impaired

New South Wales
11366 (50)
7551 (34)
2801 (13)
690 (3)
38
Victoria
9347 (76)
2447 (20)
344 (3)
49 (1)
77
Queensland
9 334 (80)
1 997 (17)
250 (2)
16 (1)
16
South Australia
7866 (83)
1098 (12)
124 (1)
389 (4)
98
Western Australia
4401 (64)
1977 (29)
419 (6)
31 (1)
27
Tasmania
4 248 (75)
1 097 (20)
142 (3)
100 (2)
100
Northern Territory
2063 (88)
247 (10)
47 (2)
0 (0)
11
Australian Capital Territory
169 (64)
76 (29)
17 (7)
0 (0)
97
Total
48793 (69)
16490 (23)
4144 (6)
1275 (2)
34

Reference condition = stream macro-invertebrates are similar in type to those at reference sites
Significantly impaired = between 20% and 50% of the expected macro-invertebrate families have been lost
Severely impaired = between 50% and 80% of the expected macro-invertebrate families have been lost
Extremely impaired = between 80% and 100% of the expected macro-invertebrate families have been lost
Source: National Land and Water Resources Audit (NLWRA) Australian Catchment, River and Estuary Assessment, 2002.

Rivers provide water for agriculture, industry and household use and sustain ecosystems that provide economic, recreational, aesthetic, social and cultural benefits.

One way to assess river water quality is to examine the aquatic biota index, which represents the response of macro-invertebrates to changes in the environment. An important source of food for fish, aquatic macroinvertebrates (such as insects, snails and worms) are useful biological indicators. They are widespread, easy to collect, relatively immobile and provide good information about the environment. Their presence, or absence, provides information about water quality. Sites with a high level of species diversity generally have good water quality.

The National Land and Water Resources Audit (NLWRA) Australian Catchment, River and Estuary Assessment 2002 was Australia's first comprehensive assessment of catchments, rivers and estuaries. The river assessment collated and interpreted data for about 14,000 reaches across the more intensively used catchments. It used a range of attributes reflecting key ecological processes at the river reach and basin scales and built on other river assessment initiatives such as AUSRIVAS. Two indices were used – an aquatic biota index using macro-invertebrates (see table above) and a river environment index (on the following page).

The NLWRA assessment of Australian rivers showed that one-third (21,909 km) of the river length assessed was to some degree impaired (has lost between 20% and 100% of the various kinds of aquatic invertebrates that should live there). New South Wales was assessed as having the poorest aquatic biota condition; approximately 50% of the river length assessed had impaired aquatic biota. Some of the most affected areas were the Georges River and Wollongong Coast basins. More than 35% of the river length assessed in the Australian Capital Territory and Western Australia had impaired biota. Between 12% and 24% of the river length assessed in the remaining states and territories had impaired biota.

RIVER ENVIRONMENT INDEX RESULTS, by state and territory, 2000

Total length of reach (km) in each category and percentage of total in parentheses
Percentage of total length with data
Largely unmodified
Moderately modified
Substantially modified
Extensively modified

New South Wales
1619 (3)
39232 (68)
17089 (29)
18 (0)
97
Victoria
3085 (20)
9042 (60)
3099 (20)
0 (0)
97
Queensland
8743 (13)
48214 (71)
10599 (16)
0 (0)
93
South Australia
299 (4)
4666 (61)
2635 (35)
0 (0)
79
Western Australia
1487 (7)
15927 (78)
2929 (14)
12 (1)
80
Tasmania
2028 (37)
3250 (59)
194 (4)
0 (0)
98
Northern Territory
9165 (66)
4630 (34)
0 (0)
0 (0)
67
Australian Capital Territory
43 (16)
191 (71)
36 (13)
0 (0)
100
Total
26468 (14)
125152 (66)
36581 (19)
31 (1)
90

Source: National Land and Water Resources Audit (NLWRA) Australian Catchment, River and Estuary Assessment, 2002.



The NLWRA’s Australian Catchment, River and Estuary Assessment 2002 also used an environment index to assess river water quality. The environment index combines the sub-indices of catchment disturbance, habitat, hydrological disturbance, and nutrient and suspended sediment load.

Ideally, a water quality index would consider important drivers of water quality, such as nutrients, suspended sediments, salt, turbidity, temperature, dissolved oxygen concentrations and toxicants. However, comprehensive data were available only for nutrient and suspended sediment loads.
Increases in nutrients and suspended sediment loads, and decreases in the extent of riparian vegetation have resulted in 85% of the river length assessed as substantially or moderately modified from natural condition.

In the Northern Territory, two-thirds of the river length assessed is in largely unmodified condition. In all other states and territories except Tasmania, more than 80% of the river length was assessed as substantially or moderately modified.




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