review of water quality in the macquarie river upstream of

Review of water quality in the Macquarie River upstream of Lake

River

Final

May 2009

A Report to DPIW WAB

L Koehnken

Technical Advice on Water

��

Review of water quality in the Macquarie River upstream of Lake River

Technical Advice on Water ii 17 May 2009

Contents Executive Summary .............................................................................................................. 1

1 Introduction ................................................................................................................... 3

1.1 Water management regions and monitoring sites ..................................................... 3

2 Background information for water quality ..................................................................... 7

2.1 Overview of 2004 – 2008 hydrology ....................................................................... 7

2.2 Presence of blue-green algal bloom in Tooms Lake ............................................... 10

2.3 Evaluating water quality condition ........................................................................ 10

3 Water quality in Water Management Regions .............................................................. 13

3.1 Upper Macquarie River-baseline water quality monitoring results ......................... 13

3.1.1 Upper Macquarie WMR River Health water quality results ............................ 15

3.2 Lower Macquarie Water Management Region-Baseline water quality monitoring

results 21

3.2.1 Lower Macquarie Water Management Region-Monitoring River Health water

quality monitoring results ............................................................................................ 22

3.3 Elizabeth River Water Management Region .......................................................... 28

3.4 Blackman River Water Management Region ......................................................... 30

3.5 Isis River Water Management Region ................................................................... 31

3.6 Pesticides .............................................................................................................. 33

4 Comparison of 2004-2008 results with historical water quality .................................... 35

4.1 Tooms River downstream Tooms Lake ................................................................. 35

4.2 Macquarie River at Mt Morriston and Trefusis ...................................................... 37

4.3 Macquarie River upstream of Elizabeth River ....................................................... 38

4.4 Macquarie River downstream of Elizabeth River................................................... 39

5 Nutrient transport / export............................................................................................ 40

5.1 Nutrient export compared to historical results ....................................................... 42

6 Synthesis and summary of water quality results ........................................................... 44

6.1 Synthesis ............................................................................................................... 44

6.2 Summary .............................................................................................................. 45

References .......................................................................................................................... 46

Appendix A – Box & whisker plots of water quality results ................................................ 47

Tooms River downstream of Tooms Lake ........................................................................... 48

Macquarie River at Trefusis ................................................................................................ 49

Macquarie River 1.25 km Upstream Elizabeth River ........................................................... 51

Macquarie River downstream Elizabeth River ..................................................................... 53


Technical Advice on Water iii 17 May 2009

List of Figures

Figure 1.1. Map of Macquarie River catchment upstream of Lake River showing major

tributaries (left) and Water Management Regions (right). ...................................................... 5

Figure 1.2. Maps of Macquarie River upstream of Lake River showing gauging stations and

Baseline Water Quality Monitoring Program sites (BWQMP) (left) and Monitoring River

Health sites (right) ................................................................................................................. 6

Figure 2.1. Summary of rainfall in Macquarie River catchment between 2004 and 2008.

Data compiled from two sites, Macquarie downstream of Elizabeth River for 2004, and

Macquarie upstream of Macquarie River for 2005 - 2008. Data supplied by DPIW. ............. 7

Figure 2.2. Hourly flow in the Macquarie River catchment Jan 2004 – December 2008. Note

log scale, data provided by DPIW. ........................................................................................ 8

Figure 2.3. Hourly flow in the Macquarie River catchment during 2005, a wet year. Note log

scale, data provided by DPIW. .............................................................................................. 8

Figure 2.4. Hourly flow in the Macquarie River catchment during 2008, a dry year. Record

includes flow from Elizabeth River. Note log scale, data provided by DPIW. ........................ 9

Figure 3.1. Hourly flow and monthly water quality results from three sites in the Upper

Macquarie Water Management Region. Data provided by DPIW. (A) = Hourly flow, (B)=

Monthly temperature (C)=Electrical Conductivity (D)=pH. ................................................. 16

Figure 3.2. Hourly dissolved oxygen (mg/L) results from the Macquarie at Trefusis (left) and

Macquarie upstream of Elizabeth River (right) monitoring sites. Data quality between July

2004 and December 2006 at the Macquarie upstream of Elizabeth River site is questionable,

and summer recorded values may be up to 2 mg/l lower than present in the river. Data

provided by DPIW. ............................................................................................................. 19

Figure 3.3. Flow (ML/day) at the Macquarie upstream and downstream of Elizabeth River

sites and Macquarie upstream of Lake River site. Also shown is discharge from Lake Leake

since mid-2007. Data provided by DPIW. .......................................................................... 21

Figure 3.4. Flow (ML/day) at the Macquarie upstream Elizabeth and Macquarie downstream

of Elizabeth River. Data provided by DPIW. ...................................................................... 21

Figure 3.5. Monthly water quality results from Macquarie downstream Elizabeth Water

Management Region. Data provided by DPIW. (A = Monthly temperature, (B)=Electrical

Conductivity, (B)=pH, (D)=Turbidity.................................................................................. 24

Figure 3.6. Flow in Elizabeth River downstream of Lake Leake Data provided by DPIW .. 28

Figure 3.7. EC and turbidity results for the Blackman River at Old Tier Rd between 2004

and 2008 obtained during river health monitoring. Data provided by DPIW. ...................... 31

Figure 5.1. Total N (top) and Total P (bottom) in kg/day at Baseline Water Quality

Monitoring sites between January 2004 and December 2008. Note log scale. ...................... 41

Figure 5.2. Total Nitrogen and Total Phosphorus results for each of the Baseline Water

Quality Monitoring sites in the Macquarie River upstream of Lake River. Data provided by

DPIW. ................................................................................................................................. 41

Figure 5.3. Total Nitrogen and Turbidity results for each of the Baseline Water Quality

Monitoring sites in the Macquarie River upstream of Lake River. Data provided by DPIW. 42


Technical Advice on Water iv 17 May 2009

List of Tables

Table 1. Water Management Regions and monitoring sites. .................................................. 4

Table 2. ANZECC 2000 default low-risk trigger values for slightly disturbed ecosystems

inTasmania. EC = electrical conductivity; DO = dissolved oxygen (% saturation, daytime

measurements); TN = total nitrogen; NOx = nitrate and nitrite; NH4+ = ammonium; TP =

total phosphorus; DRP = dissolved reactive phosphorus ANZECC (2000) .......................... 12

Table 3. Site-specific trigger values derived by DPIW based on 2003 - 2006 monthly

monitoring results for all sites except Macquarie upstream of Elizabeth which is based on

2004 – 2007 results. Values indicate status of rivers during monitoring period only and do

not indicate whether water way is degraded or not. Deviation from these values indicates

change compared to 2003 – 2006 conditions. ...................................................................... 12

Table 4. Water quality samples collected from the Upper Macquaire WMR between 2004

and 2008 for River Health monitoring (DPIW). ................................................................... 20

Table 5. Summary of Monitoring River Health water quality monitoring results for sites in

Lower Macquarie River WMR. Results provided by DPIW................................................ 27


Elizabeth River WMR. Results provided by DPIW. ........................................................... 29

Table 7. . Summary of Monitoring River Health water quality monitoring results for sites in

the Blackman River WMR. Results provided by DPIW. ..................................................... 32


the Isis River WMR. Results provided by DPIW. ............................................................... 32

Table 9. Summary of pesticide monitoring results for Macquarie River sites. Sites monitored

quarterly between October 2005 and October 2008. Data provided by DPIW. .................... 34

Table 10. Comparison of water quality results in Tooms River downstream of Tooms Lake

for 92-95, 2004-2005 and 2006-2008. 1992-1995 results from Bobbi et al., 1996. 2004 –

2008 results provided by Baseline Water Quality Monitoring Program (DPIW). ................. 36

Table 11. Comparison of water quality results in Macquarie River at Mt Morriston (1992 –

1995) with results from Macquarie River at Trefusis (2004-2005 and 2006-2008). 1992-

1995 results from Bobbi et al., 1996. 2004 – 2008 results provided by Baseline Water

Quality Monitoring Program (DPIW). ................................................................................. 37

Table 12. Comparison of water quality results in Macquarie River downstream Ross (1992 –

1995) with results from Macquarie River 1.25 km upstream Elizabeth River (2004-2005 and

2006-2008). 1992-1995 results from Bobbi et al., 1996. 2004 – 2008 results provided by

Baseline Water Quality Monitoring Program (DPIW). ........................................................ 38

Table 13. Comparison of water quality results in Macquarie River downstream Elizabeth

River between 1992 – 1995, 2004-2005, and 2006-2008. 1992-1995 results from Bobbi et

al., 1996. 2004 – 2008 results provided by Baseline Water Quality Monitoring Program

(DPIW). .............................................................................................................................. 39

Table 14. Estimated nutrient export yields (kg nutrient/ML water and kg/yr) for the Baseline

Water Quality Monitoring sites in the Macquarie River upstream of Lake River ................. 43


Technical Advice on Water 1 17 May 2009

Executive Summary

This report summarises available water quality results for the period 2004 – 2008 for the five

Water Management Regions (WMRs) identified by DPIW in the Macquarie River catchment

upstream of the confluence of the Lake and Macquarie Rivers. It forms one of a series of

background reports being prepared by DPIW as part of water management planning in the

region. The aim of the report is to characterise water quality across the catchment, based on

data collected as part of monitoring by DPIW, and provide information that will be useful

during the development of a water management plan for the catchment.

Water quality monitoring is uneven across the five WMRs, with good information available

through the Baseline Water Quality Monitoring Program for the Upper Macquarie WMR and

the upstream part of the Macquarie downstream of Elizabeth WMR. There is extremely

limited information available for the remaining WMRs (Blackman, Isis, Elizabeth) and the

downstream end of the Macquarie downstream of Elizabeth WMR.

It has been found that the hydrology of the catchment, including water extractions, flow

regulation and drought, greatly affects water quality in the river. The summer releases from

Tooms Lake and Lake Leake have different water quality characteristics as compared to

winter high flow events, so there are large variations in water quality depending on which

water source predominates, with lake derived waters tending to have lower EC and turbidity

levels as compared to the high flow events.

Within each WMR, a large proportion of water is extracted before it reaches the next

downstream WMR, resulting in a discontinuity in water quality downstream, e.g., water

quality characteristics alter considerably as one water source, such as Tooms Lake is removed

from the Macquarie, and replaced by another source, such as the Blackman or Elizabeth

River. This lack of continuity between WMRs has been found to limit the extent of water

quality impacts, such as those associated with the ongoing algal bloom in Tooms Lake.

However, the discontinuity also necessitates the management of water quality on a Water

Management Region basis.

The extended drought in the Macquarie catchment has greatly affected water quality over the

5 year period in the Upper Macquarie WMR, largely due to the establishment of a persistent

algal bloom in Tooms Lake and the downstream river since 2006. The bloom has resulted in

large and sustained increases in turbidity, total nitrogen, ammonia and total phosphorus.

These parameters are consistently above the site-specific trigger values derived by DPIW and

indicate a major change in water quality relative to previous results. Although there has been

a large increase in the concentrations of total nitrogen and phosphorous, the dissolved

components of the nutrients have remained similar to pre-2004 levels, indicating the nutrients

are associated with particulates. These water quality trends persist a short distance

downstream (to Macquarie at Trefusis) but are generally not evident at the downstream end

of the WMR (Macquarie upstream of Elizabeth River). This is most likely to be due to

settling of suspended particulates, water extractions and inflow of water major tributaries

(when is occurs).



The drought has also lead to an increase in EC values over the five year period throughout the

catchment, undoubtedly associated with the reduced inflows and ongoing evaporation.

In the upstream end of the Macquarie downstream of Elizabeth WMR, water quality has

remained relatively constant over the five year period, and similar to results collected prior to

2004. This is largely due to the inflows from the Elizabeth River remaining unchanged over

the period.

There are insufficient results to evaluate water quality trends in the other WMRs either

temporally or spatially within the Macquarie. Spot water quality samples from Blackmans

River and Blanchards Creek have found some high EC values (>1,000 µS/cm) in samples

with a large groundwater input Whether these readings are indicative of increasing salinity in

the catchments or atypical readings associated with the drought is unknown.

Nutrient export / transport has been found to be closely linked with hydrology, with nutrient

loads very high during 2005, which was a wet year, and decreasing during the subsequent

drought indicating that most nutrients are transported during the short, episodic high flow

events. Nutrient export loads are broadly consistent with loads measured in the catchment

between 1992 and 1995. An exception to this is Tooms River, where nutrient export has

increased as flow decreased due to the presence of the algal bloom, leading to much higher

export rates as compared to historic results.

Quarterly pesticide monitoring for 19 pesticides since October 2005 has found pesticides at

or above reportable limits in the Macquarie in six water samples. The six samples were

collected during two sampling periods, one associated with a high flow, high turbidity event

in July 2007 and the other during a low flow period in spring 2007. Of the six results, five

were for the broad leaf herbicide Simazine.

Water quality monitoring within the Blackman, Isis and the Macquarie downstream of

Elizabeth WMRs is inadequate to document present conditions or detect long term trends.

For effective management of these WRMs it is critical that monitoring be increased in these

catchments, especially as the development of new water infrastructure will alter flows and

water quality. Increasing monitoring in the Elizabeth River is less critical, as the Macquarie

downstream of Elizabeth monitoring site can be used to track catchment wide trends in the

Elizabeth.



1 Introduction

This report summarises water quality for the Macquarie River upstream of the Lake River.

The aim is to provide relevant background information for the formulation of a water

management plan. This report is to be used in conjunction with similar reports prepared by

DPIW regarding hydrology (DPIW, in prep.), aquatic ecology (DPIW 2008a) and CFEV

assessment (DPIW, 2008b) reports.

The catchment of the Macquarie River upstream of Lake River is extensively developed for

agriculture. Water extractions for irrigation and stock and town water supply disrupt the

continuity of flow between the five Water Management Regions (WMR) that are being

considered as part of a water management plan for the catchment. The regions are designated

as: Upper Macquarie (Macquarie above Elizabeth River), Lower Macquarie (Macquarie

downstream of Elizabeth River), Elizabeth River upstream of Macquarie River, Blackman

River upstream of Macquarie River and the Isis River upstream of Macquarie River.

This report summarises available water quality results for 2004 – 2008 for each of the WMRs.

Trends within the catchment are discussed and for sites where longer data sets are available,

the recent findings are compared with historical results. The aim of this document is to

characterise water quality across the catchment using data collected by the Water Resources

Division of DPIW and provide a status report which can inform decision-making during the

development of a water management plan for the catchment.

1.1 Water management regions and monitoring sites

The Macquarie River upstream of Lake River and its major tributaries are shown in Figure

1.1. Detailed descriptions of the catchment are contained in the Aquatic Ecology and CFEV

reports (DPIW, 2008a&b). The physical and hydrological characteristics of the catchment

were used, along with advice from the Water Management Branch of DPIW, to delineate the

five proposed Water Management Regions (WMR) (Figure 1.1). Table 1 summarises

characteristics of the WMRs and lists water quality monitoring sites within each region for

which recent water quality monitoring results from the last 5 years (2004 – 2008) are

available. The geographic distribution of the sites is shown in Figure 1.2. The sites consist of

flow gauging sites, Baseline Water Quality Monitoring Program (BWQMP) monitoring sites

and River Health (AUSRIVAS) sites. There are four BWQMP sites in the catchment: Tooms

River downstream Tooms Lake, Macquarie River at Trefusis, Macquarie River upstream of

Elizabeth River (at Fosterville) and Macquarie River downstream of Elizabeth River (at

Morningside). Physico-chemical water quality parameters and nutrients are sampled at these

sites on a monthly basis, and pesticide samples are collected on a quarterly basis. Streamflow

is also monitored continuously at these sites, as well as at two additional sites, Macquarie

River upstream Lake River and Elizabeth River downstream Lake Leake. The remainder of

the sites in Table 1 are part of the River Health (AUSRIVAS) program, where physico-

chemical water quality parameters are sampled on a biannual or less frequent basis.

At three of the BWQMP sites (Macquarie River at Trefusis, Macquarie upstream of Elizabeth

and Macquarie downstream of Elizabeth) continuous recording water quality monitoring



instruments are deployed along with gauging instrumentation, providing a continuous record

of temperature, electrical conductivity (EC), turbidity and dissolved oxygen at each site.

As shown in Table 1, three of the BWQMP sites are located within the Upper Macquarie

WMR, with the fourth one situated in the Macquarie downstream of Elizabeth WMR. Water

quality monitoring in the other three WMRs is limited to spot samples collected as part of the

River Health monitoring.

Table 1. Water Management Regions and monitoring sites.

Region Area (km

2)

Yield (ML/yr) [ML/km

2]

Monitoring Sites

Upper Macquarie

967 132,203 [4,185]

Tooms River d/s Tooms Lake (flow and BWQMP) Macquarie River at Trefusis (flow and BWQMP) Macquarie River u/s Elizabeth (at Fosterville) (flow and BWQMP) Kitty Rivulet at Trefusis (AUSRIVAS) Macquarie River off Honeysuckle Rd (AUSRIVAS) Glen Morriston Rivulet at Moulton (AUSRIVAS)

Macquarie Downstream of Elizabeth

445 48,030 [3,297]

Macquarie River d/s Elizabeth (at Morningside) (flow and BWQMP) Macquarie River u/s Lake River (at Coburg)(flow only) Macquarie River u/s Morningside gauging station (AUSRIVAS) Blanchards Creek us Valleyfield Rd (AUSRIVAS) Macquarie at Barton Rd (AUSRIVAS)

Elizabeth River

400 75,388 [5,765]

Elizabeth River d/s Lake Leake (flow only) Elizabeth River at Tea Tree Hill (AUSRIVAS) Elizabeth River at Campbell Town (AUSRIVAS) Elizabeth River at Merton Vale (AUSRIVAS)

Blackman River

559 30,835 [1,656]

Blackman River at Old Tier Rd (AUSRIVAS) Blackman River at Tunbridge (AUSRIVAS)

Isis River 327 32,663 [3,056]

Prideaux Creek at Isis Rd (AUSRIVAS) Isis River at Isis (AUSRIVAS)


Technical Advice on W

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Fig

ure

1.1

. M

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Monitorin

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sites (B

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(ri

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MACQ02 Macquarie River at Tooms Lake Rd

MACQ03 Macquarie River off Honeysuckle Rd

MACQ04 Macquarie River at Long Marsh Rd

MACQ05 Isis River at Isis

MACQ07 Prideaux Creek at Isis Rd

MACQ08 Elizabeth River at Merton Vale

MACQ09 Elizabeth River at Campbell Town

MACQ10 Elizabeth River at Tea Tree Hill

MACQ12 Blackman River at Old Tier Rd

MACQ02

MACQ04

MACQ05

MACQ07

MACQ08

MACQ09

MACQ10

MACQ12

MACQ03

MACQ13

MACQ14

MACQ16

MACQ81

MACQ36

MACQ80

MACQ82

MACQ83

MACQ84

CAMPBELL TOWN

LAKE LEAKE

MOUNT MORRISTON

YORK PLAINS

WOODBURY

TUNBRIDGE

CONARA

MACQ13 Blackman River at Tunbridge

MACQ14 Glen Morriston Rivulet at Moulton

MACQ16 Kittys Rivulet at Trefusis

MACQ36 Macquarie River at Barton Road

MACQ80 Macquarie River u/s Morningside gauging station

MACQ81 Macquarie River at bridge d/s of Hoggs Ford Road

MACQ82 Blanchards Creek upstream of Valleyfield Road

MACQ83 Macquarie River at Delmont Road

MACQ84 Macquarie River off Ashby Road (Ashby property)

ROSS



2 Background information for water quality

2.1 Overview of 2004 – 2008 hydrology

This section presents basic hydrologic information relevant to water quality from the

hydrology report and summarises rainfall for the period of interest (2004 – 2008). Data on the

hydrology of the catchment has been provided by DPIW and is generally available through

the WIST website (http://water.dpiw.tas.gov.au/wist/ui).

Figure 2.1 shows daily and cumulative annual rainfall in the Macquarie River catchment near

the confluence with the Elizabeth River for the period January 2004 – December 2008. This

record is representative of the Macquarie in the downstream end of the Upper Macquarie

WMR and the upstream end of the Macquarie downstream of Elizabeth but may differ

considerably from the headwaters of the catchment as where yields are much higher (Table 1).

The daily rainfall results show that rain events can occur at any time of the year, and the

record is punctuated with short-duration, high rainfall events.

The graph shows that annual rainfall in the catchment was 400 mm or less for four of the five

years, and approximately 700 mm in 2005. Bureau of Meteorology long-term (1964 – 1988)

rainfall records for nearby Campbelltown indicate an average annual rainfall of 563 mm, and

median rainfall of 559. The 10th-percentile rainfall for this period was 448 mm, and the 90the

percentile was 678. Compared with these long-term rainfall statistics, four of the five years

being considered have had extremely low rainfall (<10th percentile), and 2005 was very wet

(>90th percentile).

Figure 2.1. Summary of rainfall in Macquarie River catchment between 2004 and 2008. Data compiled from two

sites, Macquarie downstream of Elizabeth River for 2004, and Macquarie upstream of Macquarie River for 2005 - 2008. Data supplied by DPIW.

1/1/04 1/1/05 1/1/06 1/1/07 1/1/08 1/1/09

0

20

40

60

Daily Rainfall (mm)

0

200

400

600

800

Cum. Rainfall (mm)

Macquarie d/s Eliz. R

Macquarie u/s Eliz R.

Cum. annual rain



Hourly flow for gauged sites within the catchment is shown in Figure 2.2 for the period 2004

– 2008. Extracts for a wet year, (2005) and a dry year (2008) are shown in Figure 2.3 and

Figure 2.4, respectively.

Figure 2.2. Hourly flow in the Macquarie River catchment Jan 2004 – December 2008. Note log scale, data provided by DPIW.

Figure 2.3. Hourly flow in the Macquarie River catchment during 2005, a wet year. Note log scale, data provided by DPIW.

Jan-04 Jul-04 Jan-05 Jul-05 Jan-06 Jul-06 Jan-07 Jul-07 Jan-08 Jul-08 Jan-09

0.1

1

10

100

1000

10000

100000

Flow (ML/day)

Flow (ML/day)Tooms R d/s Tooms L

Mac at Trefusis

Mac u/s Eliz. R

Mac d/s Eliz. R

Mac u/s Lake R

Eliz R d/s L Leake

Jan-05 Mar-05 May-05 Jul-05 Sep-05 Nov-05 Jan-06

0.1

1

10

100

1000

10000

100000

Flow (ML/day)


Mac at Trefusis

Mac u/s Eliz. R

Mac d/s Eliz. R



Figure 2.4. Hourly flow in the Macquarie River catchment during 2008, a dry year. Record includes flow from

Elizabeth River. Note log scale, data provided by DPIW.

These plots show characteristics of the flow regime which are important for understanding

water quality in the catchment:

• Flow does not consistently increase with distance downstream due to water

extractions, eg, flow at the Macquarie upstream of Elizabeth site is consistently lower

than flow at Macquarie at Trefusis in spite of any inflows from the Blackman River

and other tributaries between the two sites. Similarly, flow at Macquarie upstream of

Lake River is consistently less than flow at Macquarie downstream of Elizabeth even

though the Isis and other tributaries enter between the two stations;

• During dry periods, water releases from Tooms Lake (and Lake Leake although

record is limited) provide the majority of flow in the Macquarie. This is evident in

January 05 when flow downstream of Tooms Lake is similar to that at Trefusis, and

then decreases downstream at the Macquarie upstream of Elizabeth site. Downstream

of the Elizabeth, flow is augmented by discharge from Lake Leake accounting for the

flow recorded at Macquarie downstream of Elizabeth site;

• During wet periods, discharges from Tooms Lake and Lake Leake are low (as these

storages capture water), and storm events show increasing flow in a downstream

direction (eg September 2005);

These flow characteristics directly affect water quality in the catchment in that during dry

periods, the water quality of the releases from Tooms Lake and Lake Leake will dominate

water quality in the Upper Macquarie WMR and Macquarie downstream of Elizabeth WMR

respectively, and during wet periods inputs from the catchment downstream of the lakes will

predominate. The flow records also suggest that there is little continuity between the Upper

Macquarie WMR and Macquarie downstream of Elizabeth WMR with respect to water

quality during low flow periods due to the high level of water extraction during these periods.

Jan-08 Mar-08 May-08 Jul-08 Sep-08 Nov-08 Jan-09

0.1

1

10

100

1000

Flow (ML/day)


Mac at Trefusis

Mac u/s Eliz. R

Mac d/s Eliz. R

Mac u/s Lake R

Eliz. R d/s L Leake



These aspects of the flow regime are considered in the interpretation of water quality results

in the following sections.

2.2 Presence of blue-green algal bloom in Tooms Lake

Since late 2006, a blue-green algal bloom has persisted in Tooms Lake and the river

downstream of the lake. This has lead to the water being unsuitable for human consumption

or primary contact resulting in the Council providing an alternative water supply to residents

dependant on Tooms Lake. The presence of the bloom has also affected recreational use of

the lake, with the Northern Midlands Council and Inland Fisheries Commission issuing an

advisory against primary contact or fishing.

As summarised in Section 3, the presence of the algal bloom has resulted in considerable

changes to water quality in the upper Macquarie River catchment. The factors leading to this

bloom are not known and there is insufficient data upon which reasonable inferences as to the

cause of the bloom can be made. Sustained low water level in the lake is likely to be one

significant factor.

2.3 Evaluating water quality condition

Water quality can be evaluated in several ways. ANZECC (2000) provide a method for

developing site-specific water quality guidelines based on the use of reference streams to

establish the range of natural conditions in unimpacted rivers. These water quality ranges can

then be used as guidelines in more disturbed catchments. ANZECC (2000) recognises there

may be insufficient data available for undisturbed rivers, or there may not be suitable

undisturbed rivers upon which to base guidelines, and provide default ‘trigger’ values for

highland and lowland rivers. These default triggers are not ‘guidelines’ but rather triggers

below which there is considered to be a low risk of adverse ecological effects. If triggers are

exceeded, additional investigation in the waterway is warranted.

The default ANZECC (2000) triggers are shown in Table 2. The upland river values are

applicable to waterways at elevations >150 m, which includes virtually all of the Macquarie

upstream of Lake River catchment. However, the morphology of the Macquarie River

downstream of Ross is more similar to a low land river due to the broad valley, wide

floodplain and meandering nature of the river, so application of the low land criteria may be

more appropriate for some parameters.

Since 2003, DPIW has documented water quality on a monthly basis in rivers around

Tasmania through the BWQMP. The 2003 – 2006 results have been used to establish ‘site-

specific’ triggers (not guidelines) for all sites in the monitoring network based on the present

water quality in the river. An exception is the Macquarie upstream Elizabeth River site,

which was established later than the other sites, where 2005 – 2007 results have been used to

derive the site-specific triggers.

The DPIW site specific triggers cannot be used to establish if water quality is ‘good’ or ‘bad’

in the river; they are only a benchmark to determine whether conditions have changed

relative to 2003-2006 (2005-2007 for Macquarie upstream Elizabeth). Similarly, deviations

from these values do not indicate a decline or improvement in the river, but merely a change



from the baseline (2003 – 2006) conditions. The establishment of triggers based on the

present condition of the river is consistent with the objective of the State Policy on Water

Quality Management 1997 (Tas) to maintain and enhance present water quality conditions in

the state.

DPIW’s site specific triggers are summarised in Table 3 for the 4 BWQMP monitoring sites

used in this water quality review. It is evident that the trigger values for the Macquarie River

upstream Elizabeth River site are higher compared to the other sites for Electrical

Conductivity (EC), Total Nitrogen (TN) and Total Phosphorous (TP). This is most likely

attributable to the later time-period (2005 – 2007) used to derive these triggers as compared

to the other sites. As discussed in the Section 3.1, concentrations of EC and nutrients have

increased during the prolonged drought in the catchment.

Comparing the DPIW site-specific trigger values with the ANZECC (2000) default triggers

indicates that water quality documented between 2003-2006 at the monitoring sites is

generally within the ANZECC (2000) trigger ranges with the exception of Total Nitrogen at

all sites, ammonium nitrogen at the two sites in the upper Macquarie and Total Phosphorous

at the Macquarie upstream Elizabeth site. The results are discussed in more detail in the next

section.



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Table

2. A

NZEC

C 2

000 d

efa

ult low

-risk tri

gger

valu

es for slightly d

istu

rbed e

cosy

stem

s in

Tasm

ania

. EC

= e

lect

rical conduct

ivity; D

O =

disso

lved o

xygen (%

satu

ration, daytim

e

measu

rem

ents

); T

N =

tota

l nitrogen; N

Ox =

nitrate

and n

itri

te; N

H4+ =

am

moniu

m; TP =

tota

l phosp

horus;

DR

P =

disso

lved r

eactive p

hosp

horus A

NZEC

C (2000)

Ecosystem

Type

Turb

EC

pH

DO

TN

mg/l

NOx- N

(NO2+NO3)

mg/L

NH4+- N

mg/L

TP

mg/L

DRP- P

mg/L

Upland

River

2-25

30-350

6.5-7.5

90-110

0.480

0.190

0.013

0.013

0.005

Lowland

River

6-50

125-2200

6.5-8.0

85-110

0.500

0.190

0.020

0.050

0.020

Table

3. S

ite-s

peci

fic tri

gger

valu

es deri

ved b

y D

PIW

base

d o

n 2

003 - 2

006 m

onth

ly m

onitorin

g r

esu

lts fo

r a

ll sites

exce

pt M

acq

uarie

upst

rea

m o

f Eliza

bet

h w

hic

h is base

d o

n 2

004 –

2007 r

esults. V

alu

es in

dic

ate

sta

tus of riv

ers

duri

ng m

onitorin

g p

eri

od o

nly

and d

o n

ot in

dic

ate

wheth

er

wate

r w

ay is degraded o

r n

ot. D

evia

tion from

these

valu

es in

dic

ate

s change

com

pared to 2

003 –

2006 c

onditio

ns.

Temperature

°C

Turbidity

NTU

EC

µS/cm

pH

DO

mg/L

DO

%Sat

TN

mg/L

NO3

as N

mg/L

NO2 as

N

mg/L

NH4+as

N

mg/L

TP

mg/L

DRP

as P

mg/L

Site name

20th

80th

80th

20th 80th 20th 80th 20th 80th 20th 80th 80th 80th

80th

80th

80th 80th

Tooms

River at

Tooms

Lake

7

17

8

77

87

7.0

7.7

9.0 11.2 90

103 0.709 0.005 <0.002 0.017 0.045 0.003

Macquarie

River at

Trefusis

7

18

21

100 167 7.0

7.6

8.7 11.6 90

101 0.628 0.008 <0.002 0.021 0.027 0.005

Macquarie

1.25 km

u/s

Elizabeth

River

8

19

10

208 336 7.2

7.8

8.8 11.3 86

101 1.208 0.005 0.002

0.023 0.075 0.004

Macquarie

River d/s

Elizabeth

8

20

14

124 277 6.9

7.4

8.9 11.3 91

104 0.559 0.014 0.002

0.015 0.028 0.005



3 Water quality in Water Management Regions

3.1 Upper Macquarie River-baseline water quality monitoring results

Approximately 40% of water in the Macquarie catchment is derived from the Upper

Macquarie WMR (Table 1). River flow and monthly water quality results at the three

gauging sites within the Upper Macquarie WMR (Tooms River downstream of Tooms Lake,

Macquarie River at Trefusis, Macquarie River upstream of Elizabeth River) are shown in

Figure 3.1 for the period 2004 - 2008. Box and whisker plots of the same data grouped by

year, and continuous recording results from the BWQMP sites are contained in Appendix A.

As previously noted, flow in Tooms River, which is derived from Tooms Lake, constitutes

the majority of flow in the WMR during periods when catchment inflows are low, leading to

similar flow at the Tooms and Trefusis sites during these periods (Figure 3.1 A). Flow at the

Macquarie upstream of Elizabeth River site decreases relative to the upstream sites due to

catchment extractions. During wet periods, flow from Tooms is very low, due to the

cessation of releases from the lake, and flow at the Trefusis and Macquarie upstream of

Elizabeth sites are similar due to the high catchment inflows upstream of Trefusis relative to

extractions between the two sites.

The monthly temperature results (Figure 3.1 B) show strong seasonal cycles at all three sites.

Maximum summer temperatures are highest at the Macquarie upstream of Elizabeth River

site as would be expected due to the lower altitude of the site, and longer period of time the

water has been in the river.

Electrical conductivity results (Figure 3.1 C) show uniform and increasing conductivity

values at the Tooms River site. The increase in conductivity over the 5-year period is likely

attributable to the low inflows during to the drought, and evaporation within Tooms Lake.

The conductivity spike in Tooms River in August - September 2007 is associated with a

period of very low flow and likely reflects ground water inputs and high evaporation rather

than discharge from the lake. During low flow periods, EC at the Trefusis site is similar to

the Tooms River results, but increases during periods of high flow, indicating catchment

inputs downstream of Tooms Lake have EC values higher than Tooms Lake. EC at the

Macquarie upstream of Elizabeth site are consistently (with the exception of August –

September 2007) higher than the other sites, consistent with higher EC values associated with

inflows from lowland areas. Comparing the monitoring results with the site specific triggers

in Table 3 shows that EC values have increased in Tooms relative to the 2003 – 2006

baseline. The other sites also show an increasing trend due to the drought conditions.

pH results (Figure 3.1 D) show higher values during the summer months when Tooms Lake

is the predominant flow source with very little catchment inflow. The summer values are

likely to be affected by algal blooms occurring within the lake, and since late 2006 have

frequently exceeded the upper trigger value of 7.8 in the Tooms River. High pH has been

recorded at Craigbourne Dam during blooms of blue-green algae and is generally attributable

to the consumption by algae of dissolve carbon dioxide, which normally keeps pH low.



Since the end of the last ‘wet’ year in the catchment, 2005, turbidity levels in the Tooms

River have steadily increased. Turbidity levels at the Trefusis site also increased over the

same period, but periodically decrease during storm events. Turbidity concentrations at the

Macquarie upstream of Elizabeth River site are lower than the upstream sites, presumably

due to settling of the solids and inflow of lower turbidity water. The turbidity spike upstream

of the Elizabeth River in October 2005 is associated with inflow of turbid water from the

Blackman River due to a dam failure in the sub-catchment. Similar to EC, levels have

increased steadily since 2006, with most readings from the Tooms River and Macquarie at

Trefusis sites now exceeding the site-specific trigger levels. Observations indicate that the

major source of the turbidity is algae associated with an ongoing algal bloom in Tooms Lake.

The monthly dissolved oxygen results (Figure 3.1F, shown both as concentration and percent

saturation) show some seasonality at the upstream Toooms and Trefusis sites, but little

seasonal change at the Upstream Elizabeth River site. The values are generally within the

site specific trigger range. Oxygen concentrations are dependent on biological activity and

temperature within the water and can change rapidly over short time periods. Hourly

dissolved oxygen monitoring results from the Macquarie at Trefusis and Macquarie upstream

of Elizabeth River sites (Figure 3.2) better depict seasonal changes with higher and less

variable results in winter due to the influence of temperature and the lower levels of

biological activity during these periods. Note that between July 2004 and December 2006 the

quality of data from the Macquarie upstream of Elizabeth probe is questionable, with the

probe possibly recording up to 2 mg/L lower than present in the river over summer.

Three nitrogen parameters are measured in the Baseline Water Quality Monitoring Program,

Total Nitrogen, ammonia and NOx, which is nitrate and nitrite combined. The monthly

results are shown in Figure 3.1 (G, H and I). Total and ammonia nitrogen show increasing

concentrations at the Tooms River and Macquarie at Trefusis sites during the second half of

2006. These patterns are very similar to the turbidity results suggesting the elevated

concentrations of these nutrients are associated with the algal blooms occurring in Tooms

Lake. Similar to turbidity, the concentrations of Total N and ammonia in the Macquarie

upstream of the Elizabeth River are much lower than the upstream sites, presumably due to

the inflow of lower nutrient water from other tributaries, and the settling of the algae within

the Macquarie River.

The third nitrogen parameter, NOx is low at all sites during periods of low flow indicating

that the great majority of Total Nitrogen is not available for uptake. NOx increases

substantially during the limited high flow events, with concentrations increasing downstream,

probably due to run-off from agricultural lands in the lower part of the WMR. The elevated

NOx concentrations would be unlikely to lead to algal growth during these high flow periods

due to the high water velocity in the river and low water temperature.

Total phosphorus and Dissolved Reactive Phosporus (DRP) show similar trends to the

nitrogen species. Total Phosphorus has increased since 2006 in the upstream sites in parallel

with turbidity, but the available component (DRP) shows low concentrations under these



low-flow, turbid conditions. DRP concentrations do not show an increasing trend over the

same period.

3.1.1 Upper Macquarie WMR River Health water quality results

A small number of water quality measurements have been completed in waterways in the

Upper Macquarie River Water Management Region by DPIW, which are summarised in

Table 4. These measurements are associated with the ecological assessment of the river and

are obtained in either edge or riffle habitat.

Macquarie at Longmarsh and Macquarie at Honeysuckle Road are located in the headwaters

of the Macquarie River, upstream of Tooms River. EC at these sites is generally <200µS/cm,

similar to the results from the Tooms River. The 80th percentile turbidity at the Honeysuckle

Road site is similar to the site specific trigger value derived for the Tooms River site. The

turbidity, pH and dissolved oxygen values are similar to pre-2006 values in the Tooms River

and it is likely that water quality at these sites is similar to Tooms River pre- -algal bloom.

Macquarie at Tooms Rd is situated downstream of Trefusis and the results from the three

monitoring dates show similarities to the Trefusis results, with turbidity and EC increasing

since 2006.

Kittys Rivulet enters the Macquarie River from the south, and drains agricultural lands.

There is no major storage on Kittys Rivulet, and flow can cease during dry periods. The

DPIW results show very high EC values (over 2000 µS/cm) which are likely the result of the

drought and high conductivity groundwater. Dissolved oxygen levels were also depleted at

the time of sampling, suggesting high biological activity (possibly algal growth) associated

with low flow.

Glen Morriston Rivulet originates in the Eastern Tiers and has a sizeable dam in it

headwaters. The two sampling results show moderate conductivity and low turbidity. The

dissolved oxygen, turbidity and pH results do not suggest high levels of algal activity at the

time of sampling.



(A)

(B)

(C)

(D)

Figure 3.1. Hourly flow and monthly water quality results from three sites in the Upper Macquarie Water

Management Region. Data provided by DPIW. (A) = Hourly flow, (B)= Monthly temperature (C)=Electrical

Conductivity (D)=pH.


0.1

1

10

100

1000

10000

Flow (ML/day)


Mac at Trefusis

Mac u/s Eliz. R


0.00

5.00

10.00

15.00

20.00

25.00

Temperature (C)

Tooms R d/s Tooms L

Macquarie R at Trefusis

Macquarie u/s Elizabeth R


0

100

200

300

400

500

600

EC µS/cm

Tooms R d/s Tooms L




6.00

7.00

8.00

9.00

10.00

pH

Tooms R d/s Tooms L





(E)

(F)

(F)

(G)

Figure 3.1. (continued) Monthly water quality results from three sites in the Upper Macquarie Water Management

Region. Data provided by DPIW. (E)=turbidity, (F)=Dissolved oxygen as mg/l and percent saturation, (G)=Nitrogen as Total Nitrogen.


0

20

40

60

80

Turbidity NTU

Tooms R d/s Tooms L




6

8

10

12

14

Dissolved Oxygen mg/L

Tooms R d/s Tooms L




60

80

100

120

140

160

Dissolved Oxygen %Sat

Tooms R d/s Tooms L




0.00

0.50

1.00

1.50

2.00

2.50

3.00

Total N mg/L

Tooms R d/s Tooms L





(H)

(I)

(J)

(K)

Figure 3.1 Monthly water quality results from three sites in the Upper Macquarie Water Management Region. Data

provided by DPIW. (H)=Nitrogen as Ammonia, (I)=Nitrogen as nitrate+ nitrite, (J)=Total Phosphorus,

(K)=Phosphour as Dissolved Reactive Phosphorous.


0.00

0.02

0.04

0.06

0.08

0.10

0.12

Ammonia mg/L

Tooms R d/s Tooms L




0.00

0.10

0.20

0.30

0.40

0.50

0.60

NOx mg/L

Tooms R d/s Tooms L




0.00

0.10

0.20

0.30

Total Phosphorus mg/L

Tooms R d/s Tooms L




0.00

0.01

0.02

0.03

0.04

0.05

Dissolved Reactive P mg/L

Tooms R d/s Tooms L





Figure 3.2. Hourly dissolved oxygen (mg/L) results from the Macquarie at Trefusis (left) and Macquarie upstream of

Elizabeth River (right) monitoring sites. Data quality between July 2004 and December 2006 at the Macquarie

upstream of Elizabeth River site is questionable, and summer recorded values may be up to 2 mg/l lower than present in the river. Data provided by DPIW.


0

4

8

12

16Dissolved Oxygen (mg/L) Macquarie River at Trefusis


0

4

8

12

16

Dissolved Oxygen (mg/L) Macquarie u/s Elizabeth River



ater

20

17 M

ay 2009

Table

4. W

ate

r quality

sam

ple

s collecte

d from

the

Upper

Macq

uair

e W

MR

bet

wee

n 2

004 a

nd 2

008 for

Riv

er H

ealth m

onitori

ng (D

PIW

).

Site

Date

Statistics

Temp

(C)

EC

µS/cm

Turbidity

NTU

DO

mg/L

DO

%Sat

pH

Macquarie at

Long Marsh Rd

(MACQ04)

16/04/2008

6.3

176.1

2.7

5

41.3

7.5

7/10/2008

6.9

126.6

4.03

11.95

105.9

7.11

Macquarie at

Honeysuckle Rd

(MACQ03)

26/04/2004 –

6/10/2008

Maximum

17.9

282

28.5

10.75

103.7

7.69

80th

percentile

13.44

184.88

10.72

9.662

91.3

7.63

Median

12.65

141.6

4.15

9.135

84.8

7.305

20th

percentile

11.04

125.66

1.258

7.73

77.9

6.872

Minimum

10

26.4

1.11

7.21

70.3

5.69

n=

10

10

10

10

10

10

Macquarie at

Tooms Lake Rd

(MACQ02)

26/04/2004

11.7

109.3

2.86

10.06

94.2

7.34

14/04/2008

12.9

141.8

36

8.73

83.8

8.3

6/10/2008

13.3

221

20.5

10.39

99.3

7.68

Kitty Rivulet at

Trefusis

(MACQ16)

14/04/2008

16.8

2890

5.6

4.4

43

8.5

6/10/2008

13.6

2110

7.36

7.24

69.9

7.51

Glen Morriston

Rivulet

(MACQ14)

14/04/2008

13.5

265

10.4

10.19

97.5

8.1

6/10/2008

12.1

362

3.17

10.74

99.9

7.76



3.2 Lower Macquarie Water Management Region-Baseline water quality

monitoring results

The Lower Macquarie Water Management Region extends from the confluence of the

Macquarie and Elizabeth Rivers to the confluence of the Macquarie and Lake Rivers. Flow is

gauged at the Macquarie downstream of Elizabeth site and since 2007 at the Macquarie

upstream of Lake River site. Water quality is monitored on a monthly basis at the Macquarie

downstream of Elizabeth River site. Box and whisker plots of the same data grouped by year,

and continuous recording results from the BWQMP sites are contained in Appendix A.

Figure 3.3 shows hourly flow results for the gauging sites in the Macquarie upstream and

downstream of the Elizabeth River, the discharge from Lake Leake, and discharge in the

Macquarie upstream of Lake River. Over the summer of 2007 – 2008 it is evident that the

inflow from the Elizabeth River substantially increases discharge in the Macquarie and

accounts for the majority of flow at the Macquarie downstream of Elizabeth site. It is also

evident that most of this flow is extracted from the river prior to the Macquarie upstream of

Lake River monitoring site, as flow at this site is again very low. The augmentation of

summer flow between the Macquarie upstream and downstream of the Elizabeth River sites

due to releases from Lake Leake are shown for the 2004 – 2008 period in Figure 3.4.

Figure 3.3. Flow (ML/day) at the Macquarie upstream and downstream of Elizabeth River sites and Macquarie upstream of Lake River site. Also shown is discharge from Lake Leake since mid-2007. Data provided by DPIW.

Figure 3.4. Flow (ML/day) at the Macquarie upstream Elizabeth and Macquarie downstream of Elizabeth River. Data provided by DPIW.

Jan-07 Jul-07 Jan-08 Jul-08 Jan-09

0.1

1

10

100

1000

10000

Flow (ML/day)

Flow (ML/day)Mac u/s Eliz. R

Mac d/s Eliz. R

Eliz R d/s L Leake

Mac u/s Lake R


0.1

1

10

100

1000

10000

100000

Flow (ML/day)

Flow (ML/day)Mac u/s Eliz. R

Mac d/s Eliz. R



Water quality results from the monthly Baseline Water Quality Monitoring Program are

shown in Figure 3.5 (A-J). .

Temperature results (Figure 3.5 A) show annual seasonal cycles. EC and turbidity results

(Figure 3.5B and D) also show annual cycles, with higher values associated with winter

periods. These higher values are associated with water derived from the Macquarie

catchment and Elizabeth catchment downstream of Lake Leake, which is characterised by

higher EC and turbidity compared to Lake Leake (see Elizabeth River WMR discussion).

The less well defined EC and turbidity spikes during the 2007 winter are due to very low

runoff from the catchment during this period (e.g. low flow in Figure 3.3). The trend of

increasing EC and turbidity since 2006 in the Macquarie River upstream of the Elizabeth

River is not evident in the Lower Macquarie.

pH downstream of the Elizabeth River were slightly higher during 2007 and 2008 compared

to the earlier years (80th percentile trigger 2003 – 2006 = 7.4). This is likely due to lower

flows promoting higher biological activity within the river. Dissolved oxygen concentrations

show higher concentrations (mg/L) during the winter months due to lower temperatures, but

no seasonal trend when presented as percent saturation.

The nitrogen species (Total N, ammonia, NOx) (Figure 3.5 F, G, H) all show similar patterns,

with a low baseline punctuated by two periods of elevated concentration in September 2005

and July 2007. The higher values are associated with storm events, demonstrating that the

high values are associated with catchment runoff rather than the releases from Lake Leake.

The increasing trend in nitrogen species in the Macquarie upstream of the Elizabeth River is

absent at the downstream site, showing that the extraction of water upstream of the Elizabeth

combined with inflow from the Elizabeth result in an alteration in water quality in the lower

catchment.

Total Phosphorus and Dissolved Reactive Phosphorus (Figure 3.5 I, J) show a similar pattern

to nitrogen, with elevated values associated with the same storm events. Comparing the Total

Phosphorus results with the DRP results indicates that most of the Total P occurs as

particulate P, with only a small proportion of the Total Phosphorus available as DRP.

3.2.1 Lower Macquarie Water Management Region-Monitoring River Health

water quality monitoring results

Few additional water quality results are available for the Macquarie downstream of Elizabeth

WMR except for those associated with the Monitoring River Health sampling completed in

2007 and 2008 by DPIW. Results for sites in the Macquarie downstream of Elizabeth WMR

are presented in Table 5.

The sparse sampling does not allow trends to be determined, so results were compared with

the site specific trigger values derived for the Macquarie downstream of the Elizabeth River

monitoring site to provide a comparison. The River Health values are within the trigger

limits for temperature, pH and dissolved oxygen. EC values at the River Health sites are

higher than the Macquarie River downstream of Elizabeth River trigger value for at least one

sampling. These higher values are probably attributable to a higher proportion of flow



derived from the lowland area of the catchment as compared to the Macquarie downstream of

Elizabeth River site, and the drought conditions resulting in a higher contribution of

groundwater to flow as compared to surface runoff.

The lack of regular water quality monitoring upstream of the confluence of Macquarie and

Lake Rivers prevents identification of trends in the lower part of the WMR.



(A)

(B)

(C)

(D)

Figure 3.5. Monthly water quality results from Macquarie downstream Elizabeth Water Management Region. Data provided by DPIW. (A = Monthly temperature, (B)=Electrical Conductivity, (B)=pH, (D)=Turbidity.


0.00

5.00

10.00

15.00

20.00

25.00

Temperature (C)

Macquarie d/s Elizabeth R


0

100

200

300

400

500

600

EC µS/cm



6.00

7.00

8.00

9.00

10.00

pH



0

20

40

60

80

Turbidity NTU




(E)

(E)

(F)

(G)

Figure 3.5. (continued) Monthly water quality results from Macquarie downstream Elizabeth Water Management

Region. Data provided by DPIW. (E)=Dissolved oxygen as mg/l and percent saturation, (F)=Nitrogen as Total Nitrogen, (G)= Nitrogen as ammonia.


6

8

10

12

14

Dissolved Oxygen mg/L



60

80

100

120

140

160

Dissolved Oxygen %Sat



0.00

0.50

1.00

1.50

2.00

2.50

3.00

Total N mg/L



0.00

0.02

0.04

0.06

0.08

0.10

0.12

Ammonia mg/L




(H)

(I)

(J)

Figure 3.5. (continued) Monthly water quality results from Macquarie downstream Elizabeth Water Management

Region. Data provided by DPIW. (H)= Nitrogen as nitrate+ nitrite, (I)=Total Phosphorus, (J)=Phosphour as Dissolved Reactive Phosphorous.


0.00

0.10

0.20

0.30

0.40

0.50

0.60

NOx mg/L



0.00

0.10

0.20

0.30

Total Phosphorus mg/L



0.00

0.01

0.02

0.03

0.04

0.05

Dissolved Reactive P mg/L




ater

27

17 M

ay 2009

Table

5. S

um

mary o

f M

onitorin

g R

iver H

ealth w

ate

r quality

monitorin

g r

esults fo

r sites in

Low

er

Macquarie

Riv

er W

MR

. R

esults provid

ed b

y D

PIW

.

Site

Date

Temp

(C)

EC

µS/cm

Turbidity

NTU

DO

mg/L

DO

%Sat

pH

Macquarie R u/s

Morningside

Gauge (MACQ80)

17/09/2007

13.4

206

12.6

10.38

98.6

5.5

15/04/2008

16

195.1

1.2

8.96

92.4

7.62

9/10/2008

14.2

329

0.56

8.67

84.5

8.52

Macquarie R at

Barton Rd

(MACQ36)

16/04/2008

14.3

373

0.16

8.84

99.7

7.59

7/10/2008

13.3

400

0.38

9.93

95.5

7.98

Macquarie at

Delmont Rd

(MACQ83)

15/04/2008

15.5

397

2

7.89

80.2

7.57

7/10/2008

12.7

267

2.01

11.02

106

7.7

Blanchards Ck u/s

Valleyfield Rd

(MACQ82)

15/04/2008

13.4

1711

3.3

7.41

71.3

8.1

7/10/2008

12

3140

7.14

11.01

103.6

7.77



3.3 Elizabeth River Water Management Region

The Elizabeth River is the second largest source of water within the Macquarie River,

providing ~27% of the annual yield. There is a large impoundment, Lake Leake, in the

headwaters which is managed for irrigation and town water supply releases (see Hydrology

report). Flow is monitored downstream of Lake Leake (Figure 3.6), with higher flows in

summer attributable to the managed releases. A comparison of flow in the Elizabeth

downstream of Lake Leake and the other sites in the Macquarie is in Figure 3.3.

Figure 3.6. Flow in Elizabeth River downstream of Lake Leake Data provided by DPIW

Water quality monitoring is limited in the Elizabeth. Spot water quality samples have been

collected by DPIW at the sites listed in Table 6 as part of river health investigations. As

discussed in Section 3.2.1, during periods of low catchment inflows, the majority of flow at

the Macquarie downstream of Elizabeth River gauging and monitoring site is derived from

the Elizabeth River. The results show that the summer flows derived from the Elizabeth

River have lower conductivity and turbidity compared to winter flows. This is attributable to

winter flows draining flat lying ‘marshes’ in the Elizabeth which contribute turbidity and

ionic load to the water. The presence of a sewage treatment plant downstream of

Campbelltown also contributes nutrients to the waterway (Bobbi, et al., 1996).

The results in Table 6 show an increase in conductivity in a downstream direction for the two

2008 sampling periods. In April 2008, EC increased from 34 µS/cm at Tea Tree Hill, to 115

µS/cm at Campbelltown to 134 µS/cm at Merton Vale. A similar increase, from 82 µS/cm at

Tea Tree, to 276 µS/cm at Merton Vale occurred in October 2008. In both instances the

largest increase occurred between Tea Tree Hill and Campbelltown owing to the ingress of

waters draining the flat-lying marshes. The elevated turbidity level at Tea Tree Hill in

October 2008 was associated with very low flows (DPIW, 2008B).

The other parameters, temperature, dissolved oxygen and pH are similar to values from other

sites in the Macquarie River.

Jan-07 Jul-07 Jan-08 Jul-08 Jan-09

0

20

40

60

80

Flow (ML/day)

Flow (ML/day)Eliz R d/s L Leake



ater

29

17 M

ay 2009

Table

6. Sum

mary o

f M

onitorin

g R

iver

Health w

ate

r quality

monitorin

g r

esults fo

r sites in

Eliza

beth

Riv

er

WM

R. R

esu

lts provid

ed b

y D

PIW

.

Site

Date

Temp

(C)

EC

µS/cm

Turbidity

NTU

DO

mg/L

DO

%Sat

pH

Elizabeth River at

Merton Vale

(MACQ 08)

15/04/2008

15.3

134

1.17

9.36

94.6

7.54

8/10/2008

9.8

276

7

8.85

78.4

7.41

Elizabeth River at

Campbell Town

(MACQ 09)

26/03/2004

12.7

72.7

3.83

9.34

92.3

6.35

8/10/2004

12.6

132.3

22.5

9.72

92.5

7.3

21/03/2005

15.4

70.6

4.37

12.11

112.9

7.62

10/11/2005

19

119.3

1.33

9.39

101.8

6.91

1/05/2006

11.7

90

2.79

13.03

120

6.58

6/10/2006

10.2

201

29.6

9.75

91.4

6.69

30/03/2007

13.6

113.7

2.69

10.1

100

7.53

14/09/2007

10.5

159

11.3

10.3

94

5.78

15/04/2008

14.1

115

2.89

9.3

95.2

6.78

7/10/2008

12.3

243

5.63

12.2

115

8.56

Elizabeth River at

Tea Tree Hill

(MACQ 10)

16/04/2008

9.7

34

2.73

7.29

8/10/2008

6

81.7

41.1

9.4

77.4

7.15



3.4 Blackman River Water Management Region

The Blackman River provides approximately 11% of the water yield in the Macquarie River

catchment. The Blackman joins the Macquarie downstream of the Macquarie at Trefusis

monitoring site, and upstream of the Macquarie upstream of Elizabeth monitoring site. Flow

in the catchment was substantially altered in 2004 with the construction of a large dam on the

river upstream of the Midlands Highway crossing. In October 2005, failure of the dam wall

resulted in widespread turbidity and silt deposition in the river.

Little water quality information is available for the Blackman River WMR aside from water

quality results associated with aquatic ecology monitoring completed by DPIW. The

available results are shown in Table 7.

The temperature and dissolved oxygen results are similar to values obtained in the Upper

Macquarie. pH values in the Blackman are higher than the 80th percentile trigger value for

the Upper Macquarie sites, but similar to levels measured in the Upper Macquarie during

periods of low flow and high biological activity.

EC values (Figure 3.7 A) in the Blackman may have increased since 2007 with the increase

related to the drought and reduction in flow due to the dam. Turbidity values show elevated

values during 2006 and 2007, which may be due to a slug of sediment associated with the

dam failure moving through the system. The most recent values show very low turbidity

levels.

The one data set from the Blackman River at Tunbridge contains a very high EC reading, and

a very low turbidity reading, indicative of a high dissolved solids load. At the time of sample

collection there was no flow in the river and the water was derived from groundwater. There

is insufficient water quality data to establish whether salinity is increasing in the catchment.

The other parameters are consistent with readings obtained at the other Blackman River site.



(A)

(B)

Figure 3.7. EC and turbidity results for the Blackman River at Old Tier Rd between 2004 and 2008 obtained during river health monitoring. Data provided by DPIW.

3.5 Isis River Water Management Region

The Isis River is unregulated, and contributes approximately 12% of the annual yield of the

Macquarie River upstream of Lake River. The Isis enters the Macquarie in the lower

catchment, and is the last major tributary to enter upstream of Lake River. Water quality

results obtained during river health monitoring by DPIW are listed in Table 8. The results are

similar to values at the Macquarie downstream of Elizabeth River site during periods when

Lake Leake is not a major contributor to flow. The limited results prevent the identification

of trends in the Isis River.


0

20

40

60

80

Turbidity NTU

Blackman River at Old Tier Rd


0

100

200

300

400

500

600

EC µS/cm

Blackman R at Old Tier Rd



ater

32

17 M

ay 2009

Table

7. S

um

mary o

f M

onitorin

g R

iver H

ealth w

ate

r quality

monitorin

g r

esults fo

r sites in

the B

lackm

an R

iver W

MR

. R

esults provid

ed b

y D

PIW

.

Site

Date

Temp

(C)

EC

µS/cm

Turbidity

NTU

DO

mg/L

DO

%Sat

pH

Blackman River at

Old Tier Rd

(MACQ 12)

26/04/2004

11.7

219

13

7.99

76.9

7.86

29/09/2004

12.7

130

20.9

10.24

98.6

7.75

11/04/2005

16.6

207

26.4

10.98

112.8

8.84

10/11/2005

18.3

117.7

19.6

9.92

105.6

7.54

8/05/2006

11.2

188

41.2

9.9

91.2

8.1

20/10/2006

13.1

237

77.7

9.65

95.2

8.05

14/09/2007

12.8

272

11.5

10.2

99.3

8.28

9/10/2008

15.2

382

3.82

8.55

86

8.87

Blackman River at

Tunbridge

(MACQ 13)

8/10/2008

11.7

3200

1.23

9.92

91.9

8.77

Table

8. S

um

mary o

f M

onitorin

g R

iver H

ealth w

ate

r quality

monitorin

g r

esults fo

r sites in

the

Isis R

iver W

MR

. R

esu

lts provid

ed b

y D

PIW

.

Site

Date

Temp

(C)

EC

µS/cm

Turbidity

NTU

DO

mg/L

DO

%Sat

pH

Isis River at Isis

21/03/2004

18

291

9.13

11.3

122

8.4

15/04/2008

12.6

259

3.8

8.94

85.6

7.65

7/10/2008

15

192.6

4.19

12.73

126.5

8.99

Prideaux Creek at

Isis Rd

8/10/2008

10

130.9

9.85

9.4

84.5

7.77



3.6 Pesticides

Pesticides are monitored on a quarterly basis at the four Baseline Water Quality Monitoring

Program sites (Tooms River downstream Tooms Lake, Macquarie at Trefusis, Macquarie

upstream Elizabeth River, Macquarie downstream Elizabeth River). Monitoring was

completed 13-times between October 2005 and October 2008. Table 9 contains a list of the

pesticides included in the monitoring, the reporting limit and summarises the number of times

each pesticide has been detected. Samples are filtered prior to sampling so results reflect

dissolved pesticides or those associated with fine-particulates which can pass through a

0.45µm filter.

Only two pesticides have been detected during the 13-monitoring runs, MCPA and Simazine,

which are both broad leaf herbicides. A total of 6-reportable concentrations were detected,

with 5 of those associated with the herbicide simazine. Three of the reportable results

occurred at the Macquarie upstream of the Elizabeth River site, two occurred at the

Macquarie River at Trefusis site, and one occurred at the Macquarie River downstream of the

Elizabeth River site.

Three of the results, including the highest concentration of Simazine detected, coincided with

a high flow event in July 2007, suggesting that the elevated concentrations were associated

with runoff. Because herbicides bind to soil particles, concentrations in the sample prior to

filtration were likely to have been higher. The other reportable Simazine results occurred

during a period of low flow in October 2007, with detectible concentrations at 3-sites. The

widespread occurrence of Simazine suggests multiple sources within the catchment during

the spring season.



Table 9. Summary of pesticide monitoring results for Macquarie River sites. Sites monitored quarterly between October 2005 and October 2008. Data provided by DPIW.

Pesticide Reporting Limit

Results at or above Reporting Limit

µg/L Site Date

Result µg/L

River flow ML/day

2,4-D salts & esters 0.2 None

ALPHACYPERMETHRIN 0.1 None

ATRAZINE 0.05 None

CHLOROTHALONIL 0.1 None

CHLORPYRIFOS 0.1 None

CLOPYRALID 0.2 None

FENITROTHION 0.1 None

GLYPHOSATE 10 None

HALOXYFOP-METHYL 0.1 None

HEXAZINONE 0.05 None

MCPA 0.1 Macquarie u/s Elizabeth R

17/07/08 0.1 159

METALAXYL 0.1 None

METSULFURON 0.1 None

PENDIMETHALIN 0.1 None

PERMETHRIN 0.1 None

SIMAZINE 0.05


11/07/07 18/10/07

1.27 0.23

240 25


11/07/07 18/10/07

0.16 0.67

346 3.2


18/10/07 0.14 29.2

None

SPINOSAD 0.1 None

SULFOMETURON 0.1 None

TERBACIL 0.1 None



4 Comparison of 2004-2008 results with historical water quality

Monthly water quality monitoring at the Baseline Water Quality Monitoring Program sites

began in 2004. Prior to this, there are few water quality results available for the Macquarie

catchment except for a 15-month period between 1992 and 1995 when DPIF (now DPIW)

completed water quality investigations in the South Esk Basin (Bobbi, et al, 1996), which

included monthly monitoring of several sites in the Macquarie. These historical results are

compared to the 2004 – 2008 results in the following sections. The 2004 – 2008 results have

been sub-divided into two periods, 2004 – 2005 and 2006 -2008. The earlier interval (2004 –

2005) encompasses a dry and a wet year, whereas the later interval consists of three very dry

years. The division has been made because the ongoing drought has resulted in substantial

water quality changes in the upper catchment due to the continued presence of an algal bloom

in Tooms Lake and upper Macquarie River (see Figure 3.1).

4.1 Tooms River downstream Tooms Lake

Table 10 summarises water quality results from Tooms River downstream Tooms Lake for

1992-1995, 2004-2005 and 2006-2008. Flow has decreased over the three time periods, with

mean and median flows falling by two-thirds between 1992-1995 and 2006-2008. Water

temperature and EC have increased over the same period, suggesting lower flows have lead

to greater warming and higher ionic load. pH has also increased, which is probably

attributable to greater biological activity in the water way due to the extended algal growth.

Ammonia and total phosphorous have increased over the three monitoring periods, but nitrate

and DRP, which are biologically available nutrients have not, indicating that the export of

nutrients is primarily in particulate form.

In summary, there are substantial changes to water quality in Tooms Lake over the three

monitoring periods due to the drought and persistence of an algal bloom in the lake and upper

catchment.



Table 10. Comparison of water quality results in Tooms River downstream of Tooms Lake for 92-95, 2004-2005 and

2006-2008. 1992-1995 results from Bobbi et al., 1996. 2004 – 2008 results provided by Baseline Water Quality Monitoring Program (DPIW).

Parameter Years Unit Count Max Min Mean Median

Flow* 92-95 ML 15 180.6 0.69 41.8 30.5

04-05 ML 731* 260 0.30 23.2 17.9

06-08 ML 1096* 60.5 0.04 12.7 9.3

Temperature 92-95 Celcius 15 18.2 4.6 10.78 10.5

04-05 Celcius 25 19.4 4.2 11.7 11.6

06-08 Celcius 36 22.3 3.8 12.2 12.1

EC 92-95 µS/cm 15 88 69 76 74

04-05 µS/cm 25 128 34 81 80

06-08 µS/cm 36 519 77 123 110

pH 92-95 15 7.3 6.4 6.9 6.9

04-05 22 8.9 6.2 7.3 7.3

06-08 36 9.8 6.3 7.8 7.8

Ammonia-N 92-95 mg/L 15 0.012 <0.005 0.006 <0.005

04-05 mg/L 25 0.021 0.003 0.013 0.015

06-08 mg/L 36 0.113 0.002 0.043 0.043

Nitrate-N 92-95 mg/L 15 0.2 0.003 0.04 0.03

04-05 mg/L 25 0.009 0.002 0.004 0.003

06-08 mg/L 36 0.2 0.002 0.012 0.005

Dissolved Reactive P

92-95 mg/L 15 0.008 0.003 0.0054 0.006

04-05 mg/L 25 0.004 0.002 0.0028 0.003

06-08 mg/L 36 0.009 0.002 0.0034 0.003

Total P 92-95 mg/L 15 0.04 0.01 0.017 0.015

04-05 mg/L 25 0.053 0.014 0.027 0.024

06-08 mg/L 36 0.222 0.016 0.102 0.102 *Maximum daily average flows based on hourly flow data



4.2 Macquarie River at Mt Morriston and Trefusis

In the 1992 - 1995 monitoring, water quality samples were collected from the Macquarie

River at Mt Morriston, which is located downstream of the confluence with the Blackman

River, and upstream of Ross. In Table 11 these results are compared with the 2004 – 2008

results from the Macquarie River at Trefusis site, which is located upstream of the Blackman

River. Direct comparison between the data sets is difficult because of the different locations,

but both can be considered to be representative of the upper Macquarie catchment. At the

time of the 1992 – 1995 monitoring the Blackman River was largely unregulated.

The lower flows shown in Table 11 for the 2004 – 2005 and 2006 – 2008 data sets reflects

the smaller catchment area upstream of Trefusis as compared to the DPIF’s monitoring site,

and the ongoing drought conditions. The relative decrease in conductivity between the Mt

Morriston results and the Trefusis results is probably due to the inclusion of flow from the

Blackman River in the Mt Morriston results. As shown in Table 7, EC in the Blackman is

higher than in the Tooms River (Figure 3.1). Parameters which show increases over time

include pH, ammonia and total. This is similar to the trend observed in the Tooms River

results and is likely associated with nutrient input from the algal bloom in the upper

catchment.

Table 11. Comparison of water quality results in Macquarie River at Mt Morriston (1992 – 1995) with results from

Macquarie River at Trefusis (2004-2005 and 2006-2008). 1992-1995 results from Bobbi et al., 1996. 2004 – 2008 results provided by Baseline Water Quality Monitoring Program (DPIW).


Flow 92-95 ML 15 702 19 149 61

04-05 ML 732* 6111 7 110 28

06-08 ML 1021 949 1.3 22 12


04-05 Celcius 24 19.4 4.2 11.8 10.7

06-08 Celcius 41 21.8 4.3 13.0 12.7

EC 92-95 µS/cm 16 474 93 169 142

04-05 µS/cm 24 232 92 133 115

06-08 µS/cm 41 231 88 143 136

pH 92-95 15 7.5 5.6 6.7 6.9

04-05 23 7.8 6.5 7.2 7.2

06-08 39 8.7 6.2 7.5 7.6

Ammonia-N 92-95 mg/L 15 0.008 <0.005 <0.005 <0.005

04-05 mg/L 24 0.03 0.005 0.013 0.012

06-08 mg/L 36 0.085 0.002 0.031 0.028

Nitrate-N 92-95 mg/L 14 0.05 <0.001 0.017 0.012

04-05 mg/L 24 0.087 0.002 0.010 0.003

06-08 mg/L 36 0.144 0.002 0.011 0.004


92-95 mg/L 15 0.009 <0.001 0.004 0.003

04-05 mg/L 24 0.007 0.002 0.004 0.004

06-08 mg/L 36 0.042 0.002 0.004 0.003

Total P 92-95 mg/L 15 0.021 0.009 0.014 0.013

04-05 mg/L 24 0.105 0.013 0.025 0.022




4.3 Macquarie River upstream of Elizabeth River

During the 1992-1995 State of the River monitoring, samples were collected from the

Macquarie River downstream of Ross. Since 2004, samples have been collected 1.25km

upstream of the Elizabeth River, which is approximately 10 km downstream of the Ross site.

No major tributaries enter the Macquarie between the two monitoring sites, but water

extraction and diffuse catchment inflows may affect water quality, and the comparison should

be considered indicative only. No flow results are available for the 1992 – 1995 dataset.

Similar to the upstream sites, temperature EC and pH have increased with time consistent

with the drought scenario. In contrast, mean and median nutrient concentrations do not show

an increasing trend, suggesting that the influence of the algal bloom in the upper catchment

diminishes with distance downstream due to dilution, settling of algae and water extractions.

Maximum nutrient concentrations do increase over time, which is likely due to higher

nutrient concentrations associated with periods of low flow when the majority of water is

derived from Tooms Lake.

Table 12. Comparison of water quality results in Macquarie River downstream Ross (1992 – 1995) with results from

Macquarie River 1.25 km upstream Elizabeth River (2004-2005 and 2006-2008). 1992-1995 results from Bobbi et al., 1996. 2004 – 2008 results provided by Baseline Water Quality Monitoring Program (DPIW).


Flow 92-95 ML

04-05 ML 524* 3089 <0.01 140 21

06-08 ML 1108* 879 <0.01 14 6.5


04-05 Celcius 14 21.4 5.1 13.4 14.3

06-08 Celcius 36 23.9 4.9 13.8 13.0

EC 92-95 µS/cm 15 287 141 209 214

04-05 µS/cm 14 416 144 257 242

06-08 µS/cm 36 436 181 290 291

pH 92-95 12 7.5 6.2 6.7 6.6

04-05 14 9.3 6.6 7.4 7.3

7.3 06-08 35 8.8 6.6 7.8 7.8

Ammonia-N 92-95 mg/L 15 <0.005 <0.005 <0.005 <0.005

04-05 mg/L 9 0.017 0.009 0.012 0.01

06-08 mg/L 36 0.065 0.002 0.014 0.01

Nitrate-N 92-95 mg/L 15 0.02 <0.005 0.008 0.006

04-05 mg/L 9 0.164 0.02 0.021 0.003

06-08 mg/L 36 0.585 0.002 0.022 0.002


92-95 mg/L 15 0.015 0.002 0.007 0.007

04-05 mg/L 9 0.012 0.002 0.005 0.003

06-08 mg/L 36 0.008 0.002 0.003 0.002

Total P 92-95 mg/L 15 0.036 0.01 0.02 0.021

04-05 mg/L 9 0.059 0.012 0.027 0.017




4.4 Macquarie River downstream of Elizabeth River

Similar to the other monitoring sites, there has been a large reduction in median flows over

the three data sets, however there has been relatively little change to water quality results

over the period. This is likely due to the majority of flow at the Macquarie downstream of

the Elizabeth River site being derived from Lake Leake and the Elizabeth River catchment

(summer months). This has lead to limited impact on water quality from the algal bloom in

the upper catchment, and there have not been prolonged blooms in Lake Leake or the

Elizabeth River.

Table 13. Comparison of water quality results in Macquarie River downstream Elizabeth River between 1992 – 1995,

2004-2005, and 2006-2008. 1992-1995 results from Bobbi et al., 1996. 2004 – 2008 results provided by Baseline

Water Quality Monitoring Program (DPIW).


Flow 92-95 ML 42 3723 14.3 238 45

04-05 ML 731 17684 8.3 294 56

06-08 ML 1111 1430 0.05 42 24


04-05 Celcius 22 22.1 5.9 14.0 15.1

06-08 Celcius 39 22.3 6.2 14.1 12.8

EC 92-95 µS/cm 39 294 110 198 198

04-05 µS/cm 23 388 97 210 216

06-08 µS/cm 39 313 115 207 203

pH 92-95 39 7.8 5.6 6.8 6.8

04-05 23 8.0 6.4 7.3 7.3

06-08 38 8.3 6.7 7.4 7.3

Ammonia-N 92-95 mg/L 42 0.012 <0.005 0.006 <0.005

04-05 mg/L 23 0.03 0.002 0.013 0.012

06-08 mg/L 36 0.033 0.002 0.009 0.007

Nitrate-N 92-95 mg/L 42 0.19 <0.001 0.027 0.01

04-05 mg/L 23 0.12 0.002 0.015 0.005

06-08 mg/L 36 0.368 0.002 0.019 0.004


92-95 mg/L 42 0.02 <0.001 0.007 0.006

04-05 mg/L 23 0.011 0.002 0.004 0.004

06-08 mg/L 36 0.007 0.002 0.003 0.002

Total P 92-95 mg/L 42 0.06 0.007 0.022 0.021

04-05 mg/L 23 0.057 0.010 0.022 0.019

06-08 mg/L 36 0.101 0.008 0.021 0.013



5 Nutrient transport / export

Nutrient transport in the Macquarie River has been estimated using the available nutrient

monitoring results and flow record. Nutrient concentrations and average daily flow results

were used to determine the flux (kg/day) of Total Nitrogen and Total Phosphorus at each site

for each monitoring day. These values were used to estimate nutrient export yield (kg/ML)

and estimate the annual export of nutrients at each site (kg/yr). The results are shown in

Figure 5.1, and Table 14.

There is strong seasonality in the Tooms River downstream of Tooms Lake results, with low

fluxes coinciding with winter periods, when releases from the lake are limited (Figure 5.1).

At the other sites, large peaks coincide with high flow events. During these periods nutrient

fluxes increase by several orders of magnitude, and increase in a downstream direction.

There is a strong and similar correlation between Total Nitrogen and Total Phosphorus results

at each site (Figure 5.2) with approximately 15-times more TN transported as compared to

TP. The decreasing concentrations of TN and TP in a downstream direction are also evident

in Figure 5.2 with maximum levels of TN downstream of the Elizabeth River being <1.5

mg/l as compared to >3.0 mg/L in Tooms River.

In 2004 and 2005, nutrient fluxes during the dry periods were similar at all four monitoring

sites, however in 2007 and 2008 nutrient fluxes at the Tooms and Macquarie at Trefusis sites

are higher during low flow periods compared with the downstream sites (Figure 5.1). This is

attributable to the ongoing algal bloom present in Tooms Lake combined with the extraction

of water between the Trefusis site and the Macquarie upstream of Elizabeth River site.

As discussed in Sections 3.1and 3.2, the majority of TN and TP are associated with

particulates rather than the dissolved species (NOx, ammonia, DRP). Figure 5.3 compares

turbidity results from each of the monitoring sites with TN results, and shows a good

correlation between elevated TN concentrations and elevated turbidity levels. The elevated

values are generally associated with the water derived from Tooms Lake affected by the

ongoing algal bloom in the lake.

In the Macquarie at Trefusis and Macquarie downstream of Elizabeth data sets there are

several elevated turbidity values which correspond to low TN results. These are

predominantly associated with high flow events during winter 2004 and 2006. The sediment

mobilised by these flow events contributed turbidity, but a lower nutrient load compared to

Tooms Lake. There are fewer high turbidity low TN readings for the Macquarie upstream of

Elizabeth presumably because the water has been diluted by other inflows and/or the turbidity

has settled upstream of the site.



Figure 5.1. Total N (top) and Total P (bottom) in kg/day at Baseline Water Quality Monitoring sites between January 2004 and December 2008. Note log scale.

Figure 5.2. Total Nitrogen and Total Phosphorus results for each of the Baseline Water Quality Monitoring sites in

the Macquarie River upstream of Lake River. Data provided by DPIW.


0.01

0.1

1

10

100

1000

10000

TN Export (kg/day)

Tooms R d/s Tooms L





0.001

0.01

0.1

1

10

100

1000

TP Export (kg/day)

Tooms R d/s Tooms L




0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5TN (mg/L)

0.00

0.05

0.10

0.15

0.20

0.25

TP (mg/L)

Tooms R ds Tooms Lake


Macquarie R u/s Elizabeth R

Macquarie R d/s Elizabeth R



Figure 5.3. Total Nitrogen and Turbidity results for each of the Baseline Water Quality Monitoring sites in the Macquarie River upstream of Lake River. Data provided by DPIW.

The coefficients of nutrient yields (kg/ML) in Table 14 range from 0.3 to 2.4 kg/ML Total

Nitrogen and about 0.01 to 0.17 kg/ML Total Phosphorus with the higher values associated

with the Tooms River site. These higher coefficients are undoubtedly associated with the

algal bloom in Tooms Lake and the upper Macquarie, with the export coefficients increasing

from ~0.5 to 2.4 kg TN/ML and from 0.02 to 0.17 kg TP/ML over the five year period due to

the bloom.

The effect of a wet-year on nutrient export is evident from the 2005 results, showing a large

increase downstream in the annual loads. The variability in flow strongly affects the most

downstream site, Macquarie downstream of Elizabeth, where TN and TP loads range from

2444 kg TN/yr and 73 kg TP/yr during a very dry year to 172,000 kg TN/yr and 2974 kg

TP/yr during a wet year. The upstream sites show less variability due to higher yields

coinciding with low flows (e.g., as flow decreases export yield increases due to the bloom).

5.1 Nutrient export compared to historical results

Between 1992 and 1995 Bobbi et al. (1996), monitored the Macquarie River catchment and

estimated nutrient export yields. The yield estimates were completed by a regression analysis

using flow and nutrient concentrations, with the hydrograph then converted to a nutrient

export curve. This approach was not applicable to the 2004 – 2008 monitoring results

because of a lack of correlation between flow and nutrients since 2006 in the upper

Macquarie due to the persistent algal bloom. Instead, the fluxes calculated from monthly

monitoring results (presented in the previous section) have been used to estimate annual

yields of TN and TP. Because different methods were used to derive the results should only

be compared at a broad level.

The nutrient export yields for each of the monitoring sites are listed in Table 14, along with

the estimated yields derived by Bobbi et al., (1996). The results show a continual increase in

nutrient export at the Tooms River site for both TN and TP. This is undoubtedly related to

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5TN (mg/L)

0

10

20

30

40

50

60

70

Turbidity (NTU)

Tooms R ds Tooms Lake


Macquarie R u/s Elizabeth R

Macquarie R d/s Elizabeth R



the ongoing algal bloom in Tooms Lake. At the downstream sites, nutrient yields are lowest

in 2008. This is due to the lack of high flows in the catchment during the drought.

Compared to the historic results, the range of the 2004 – 2008 results is similar, except for the

Tooms Lake site (due to the bloom) and in 2008 at the Macquarie downstream of Elizabeth

site.

Table 14. Estimated nutrient export yields (kg nutrient/ML water and kg/yr) for the Baseline Water Quality Monitoring sites in the Macquarie River upstream of Lake River

TN Export Year

Tooms R kg/ML (kg/yr)

Macquarie at Trefusis kg/ML (kg/yr)

Macquarie u/s Elizabeth

kg/ML (kg/yr)

Macquarie d/s Elizabeth kg/ML (kg/yr)

2004 0.5 (3,576)

0.6 (19,676)

0.5 (29,277)

2005 0.6 (3,847)

1.1 (52,529)

1.8 (120,191)

1.1 (172,193)

2006 0.7 (5,529)

0.7 (6,864)

0.5 (2,436)

0.4 (8,107)

2007 1.5 (4,836)

0.6 (6,864)

1.5 (12,652)

1.3 (25,317)

2008 2.4 (9,154)

1.7 (7,126)

0.3 (614)

0.3 (2,444)

1992 – 1995 (DPIF)

0.74 – 1.3 (37,580-182,107)

TP Export

2004 0.020 (143)

0.027 (885)

0.022 (1,288)

2005 0.029 (186)

0.055 (2,626)

0.092 (6,143)

0.054 (2,974)

2006 0.042 (332)

0.034 (333)

0.017 (83)

0.019 (385)

2007 0.088 (284)

0.029 (332)

0.091 (767)

0.077 (1,500)

2008 0.168 (641)

0.095 (398)

0.012 (25)

0.009 (73)

1992 – 1995 (DPIF)

0.017 (24-230)

0.018-0.095* (271-5700)

0.028-0.047 (1234-12,813)

DPIF results from Bobbi et al., 1996. *Results from Mt Morriston



6 Synthesis and summary of water quality results

6.1 Synthesis

The water quality monitoring results from the Macquarie River catchment upstream of Lake

River show the following characteristics and trends:

• The hydrology of the catchment significantly affects water quality. The storage of

winter flows for release during summers affects the quality (and quantity) of water in

the river;

• During 2004 – 2005, water quality results were similar to historic values;

• The prolonged drought in the Macquarie catchment since 2006 has affected water

quality in a number of ways:

o Maximum river temperatures have increased by a small amount;

o Electrical conductivity readings have increased due to a greater contribution

from groundwater and evaporation in the river;

o Low inflows to Tooms Lake have lead to low lake levels and long residence

time of water in the impoundment. This has contributed to the establishment

of a prolonged blue-green algal bloom in the lake and downstream river;

o The excessive algal growth has increased pH, ammonia and total nitrogen and

total phosphorous levels in the Tooms River and the Macquarie River at

Trefusis;

o The presence of algae in the lake and river has greatly increased turbidity in

the river during periods of low flow;

o Downstream of Trefusis, catchment inflows, combined with water extractions,

reduces the impact of the bloom on water quality;

o Nutrient export has decreased relative to historic results during the dry years

due to most nutrient transport occurring during periods of high flow;

o Nutrient export from Tooms Lake has increased during the drought due to the

ongoing algal bloom resulting in elevated nutrient levels during periods of low

flow;

• The Elizabeth River exerts a large influence on water quality downstream of the

confluence as it contributes the majority of flow during dry periods. The Elizabeth

has not experienced prolonged algal blooms during the drought;

• Pesticides have been detected in the Macquarie during 2 sampling periods, one

associated with a high flow, high turbidity event and the other during a low flow

period in the spring;

• Nutrient export from the catchment increases substantially during high flow events at

all sites except Tooms River downstream of Tooms Lake, where the ongoing algal

bloom has lead to increased nutrient export during periods of low flow;



• There are insufficient water quality results to identify ranges or water quality trends in

the Blackman, Isis or Elizabeth River Water Management Regions, or in the lower

reaches of the Lower Macquarie River WMR;

• The Baseline Water Quality Monitoring Program provides excellent information

about water quality in the upper Macquarie catchment and immediately downstream

of the Elizabeth River.

6.2 Summary

Water quality in the Macquarie River catchment provides a good understanding of the Upper

Macquarie WMR and reaches of the Macquarie River between the Elizabeth River and the

Lake River. There is very limited information available for the other WMRs which prevents

the detection of water quality issues or identification of trends.

Major water quality issues in the catchment include the prolonged and ongoing algal bloom

in Tooms Lake and the upper Macquarie River which has affected nutrient, pH, DO and

turbidity levels in the Upper Macquarie WMR. The persistence of the bloom is related to the

ongoing drought, and it is unlikely conditions will change until Tooms Lake receives

considerable inflow.

In several of the tributaries of the Macquarie there are sporadic elevated electrical

conductivity levels which may indicate salinity is increasing over time in the catchment, but

there are insufficient spatial or temporal results to identify trends. In the Upper Macquarie

WMR EC values have increased steadily since 2006, but remain at relatively low levels.

Downstream of the Elizabeth River, EC values in the Macquarie have not increased reflecting

the continued inflow of water from Lake Leake.

Under base-flow conditions, the high volume of water extracted relative to base flow results

in a decrease in river discharge between the Macquarie at Trefusis and the Macquarie

upstream of the Elizabeth River monitoring sites, and between the Macquarie downstream of

the Elizabeth River and upstream of Lake River monitoring sites. These extractions result in

a discontinuity of water quality in the river, with the upstream WMR having little influence

on downstream water quality during periods of low flow. Under normal conditions, this

would be considered a risk to water quality, as there is little dilution through flow

augmentation with distance downstream, making each WMR vulnerable to local change or

inputs. Under the present drought / algal bloom conditions, this discontinuity between the

regions actually limits the impacts of the bloom to the Upper Macquarie WMR.

If each of the WMRs is to be managed somewhat independently, it is critical that water

quality monitoring in the Elizabeth, Blackman, Isis and Macquarie downstream of Elizabeth

WMR be increased such that extractions can be managed in a manner that maintains suitable

water quality for users and the environment.



References

ANZECC/ARMCANZ, 2000, Australian and New Zealand Guidelines for Fresh and Marine

Water Quality, Australian and New Zealand Environment and Conservation Council,

Agriculture and Resource Management Council of Australia and New Zealand.

Bobbi, C., Fuller, D., and Oldmeadow, D, 1996, A technical document presenting data

collected during a study of rivers of the South Esk, Meander and Macquarie

Catchments during the period 1992 – 1995. Resource Assessment Branch, Dept.

Primary Industries and Fisheries (DPIF, now DPIW).

DPIW, 2008a, River Health of the Macquarie River Catchment. Water Assessment Aquatic

Ecology Report Series, WA08/53 ISSN 1835-9523

DPIW, 2008b, Assessment of freshwater ecosystem values in the Macquarie River Catchment.

Water Assessment Aquatic Ecology Report Series WA 08/51 ISSN 1835-9523.

DPIW, 2008c, Site-specific trigger values for physico-chemical indicators monitored under

the DPIW Baseline Water Quality Monitoring Program. Water Assessment Water

Quality Report Series WA 08/52 ISSN 1835-954X



Appendix A – Box & whisker plots of water quality results



Tooms River downstream of Tooms Lake

Box and whisker plots of monthly monitoring results from Tooms River downstream of Tooms Lake grouped by year.

Boxes encompass the 25th – 75

th percentile values, ‘whiskers’ show minimum and maximum values. Data from by

DPIW Baseline Water Quality Monitoring Program. Note log scale.

0.001

0.01

0.1

1

10

TN NH3 NO3 NO2 TP DRP

Tooms R d/s Tooms Lake2004

0.001

0.01

0.1

1

10



0.001

0.01

0.1

1

10



0.001

0.01

0.1

1

10



0.001

0.01

0.1

1

10





Macquarie River at Trefusis

Box and whisker plots of monthly monitoring results from Macquarie River at Trefusis grouped by year. Boxes

encompass the 25th – 75

th percentile values, ‘whiskers’ show minimum and maximum values. Data from by DPIW

Baseline Water Quality Monitoring Program. Note log scale.

0.001

0.01

0.1

1

10


Macquarie R at Trefusis2004

0.001

0.01

0.1

1

10



0.001

0.01

0.1

1

10



0.001

0.01

0.1

1

10



0.001

0.01

0.1

1

10





BWQMP continuous recording results from Macquarie at Trefusis.


0

5

10

15

20

25

30

Temp (C)



0

100

200

300

400

EC (µS/cm)



0

20

40

60

80

Turbidity (NTU)



6

8

10

12

14

Dissolved Oxygen (mg/L) Macquarie River at Trefusis



Macquarie River 1.25 km Upstream Elizabeth River

Box and whisker plots of monthly monitoring results from Macquarie River 1.25 km upstream Elizabeth River

grouped by year. Boxes encompass the 25th – 75

th percentile values, ‘whiskers’ show minimum and maximum values.

Data from by DPIW Baseline Water Quality Monitoring Program. Note log scale.

0.001

0.01

0.1

1

10


Macquarie u/s Elizabeth R2005

0.001

0.01

0.1

1

10



0.001

0.01

0.1

1

10



0.001

0.01

0.1

1

10





BWQMP continuous recording results from Macquarie upstream Elizabeth River. Dissolved oxygen data quality

between July 2004 and December 2006 at the Macquarie upstream of Elizabeth River site is questionable, and recorded values may be up to 2 mg/l lower than present in the river (K. Hoyle, pers com).


0

5

10

15

20

25

30

Temp (C)

Macquarie u/s Elizabeth River


0

200

400

600

800

EC (µS/cm)



-40

0

40

80

120

160

200

Turbidity (NTU)



0

4

8

12

16

Dissolved Oxygen (mg/L) Macquarie u/s Elizabeth River



Macquarie River downstream Elizabeth River

Box and whisker plots of monthly monitoring results from Macquarie River downstream Elizabeth River grouped by

year. Boxes encompass the 25th – 75

th percentile values, ‘whiskers’ show minimum and maximum values. Data from

by DPIW Baseline Water Quality Monitoring Program. Note log scale.

0.001

0.01

0.1

1

10


Macquarie R d/s Elizabeth R2004

0.001

0.01

0.1

1

10



0.001

0.01

0.1

1

10



0.001

0.01

0.1

1

10



0.001

0.01

0.1

1

10





BWQMP continuous recording results from Macquarie downstream Elizabeth River. Dissolved oxygen data not presented due to extended periods of missing record.


0

5

10

15

20

25

30

Temp (C)

Macquarie d/s Elizabeth River


0

200

400

600

800

EC (uS/cm)



0

40

80

120

160

200

Turbidity (NTU)


review of water quality in the macquarie river upstream of

Documents