Using water quality and infauna data to understand the
environmental impacts of wastewater discharge
Peter Crockett and Scott Chidgey
A tale of two outfalls
Altona STPMurray Goulburn Co-op
2004/2005
2005/2006
2006/2007
2007/2008
2008/2009
2009/2010
2010/2011
2011/2012
2012/2013
2013/2014
0
50
100
150
200
250
300
350
Total nitrogen loads
Altona STP
Murray Goulburn LeongathaTonnes
Distance (≈ Exposure-1 )
Response
Dose-Response
Water Quality
Infauna
Altona Outfall
Total phosphorus concentrations as
proportion of background median
Median background
2.5 X background
5 X background
10 X background
20 X background
>20 X background
307500 307550 307600 307650 307700 307750 307800 307850
Easting (metres)
5804700
5804750
5804800
5804850
5804900
5804950
5805000
5805050
No
rth
ing
(m
etre
s)
0
100
250
500
1000
2000
307500 307550 307600 307650 307700 307750 307800 307850
Easting (m etres)
5804700
5804750
5804800
5804850
5804900
5804950
5805000
5805050
No
rth
ing
(m
etre
s)
0
100
250
500
1000
2000
307500 307550 307600 307650 307700 307750 307800 307850
Easting (metres)
5804700
5804750
5804800
5804850
5804900
5804950
5805000
5805050
No
rth
ing
(m
etre
s)
307500 307550 307600 307650 307700 307750 307800 307850
Easting (m etres)
5804700
5804750
5804800
5804850
5804900
5804950
5805000
5805050
No
rth
ing
(m
etre
s)
June 2006Background median TP: 0.14 mg/L
April 2008Background median TP: 0.09 mg/L
March 2010Background median TP: 0.10 mg/L
March 2011Background median TP: 0.18 mg/L
Altona OutfallAbundance by infauna family, 2004-2015
≤ 50 m % ≥ 100 m %
Capitellidae 24 Galeommatidae 19 Galeommatidae 15 Capitellidae 12 Phoxocephalidae 9 Phoxocephalidae 10 Magelonidae 7 Magelonidae 10 Opheliidae 6 Opheliidae 7 Gynodiastylidae 4 Gynodiastylidae 6 Orbiniidae 3 Orbiniidae 4 Nematoda 3 Veneridae 4 Corophiidae 2 Cirolanidae 3 Veneridae 2 Spionidae 2
Capitellidae
Galeommatidae
Altona OutfallInfauna abundance, 2004-2015
250 100 50 25 5 5 25 50 100 250South North
0
5000
10000
15000
20000
25000
30000
35000
40000MedianReference 80th percentileReference 20th percentile
Distance from outfall (m)
Infa
una
per s
quar
e m
etre
Altona OutfallAbundance of Capitellidae, 2004-2015
Jan-
04
Nov
-05
Apr-
06
Nov
-07
Jan-
08
Dec
-08
Mar
-10
Apr-
11
Oct
-11
Jul-1
2
Feb-
13
Apr-
13
Jun-
13
Mar
-14
Mar
-15
0
500
1000
1500
2000
2500
3000
3500
4000
≤ 50 m ≥ 100 m
Aver
age
num
ber p
er sq
uare
met
re
399850 399900 399950 400000 400050 400100
Easting
October 2010 - background median total phosphorus: 0.010 mg/L
5709000
5709050
5709100
5709150
5709200
5709250
No
rth
ing
-1
1
2
5
10
20
October 2010Background median TP: 0.010 mg/L
399850 399900 399950 400000 400050 400100
Easting
August 2012 - background median total phosphorus: 0.017 mg/L
5709000
5709050
5709100
5709150
5709200
5709250
No
rth
ing
-1
1
2
5
10
20
August 2012Background median TP: 0.017 mg/L
399850 399900 399950 400000 400050 400100
Easting
December 2013 - background median total phosphorus: 0.010 mg/L
5709000
5709050
5709100
5709150
5709200
5709250
No
rth
ing
-1
1
2
5
10
20
December 2013Background median TP: 0.010 mg/L
399850 399900 399950 400000 400050 400100
Easting
March 2015 - background median total phosphorus: 0.012 mg/L
5709000
5709050
5709100
5709150
5709200
5709250
No
rth
ing
-1
1
2
5
10
March 2015Background median TP: 0.012 mg/L
Venus Bay Outfall
Total phosphorus concentrations as
proportion of background median
2 X background
5 X background
10 X background
Median background
1.5 X background
>10 X background
Venus Bay OutfallAbundance by infauna family, 2004-2015
Trochidae (Bankivia sp.)
Cirolanidae
Baseline surveys % Operational surveys % Trochidae 60 Magelonidae 28 Corophiidae 26 Cirratulidae 12 Magelonidae 3 Terebellidae 8 Cirolanidae 2 Lumbrineridae 7 Terebellidae 1 Urohaustoriidae 5 Urohaustoriidae 1 Trochidae 4 Harpactocoid 1 Sigalionidae 4 Ophiuroidea 1 Ophiuroidea 3 Sigalionidae 0 Spionidae 3 Lumbrineridae 0 Sipuncula 3
Venus Bay OutfallInfauna abundance, 2004-2015
Feb-
04
May
-05
Mar
-06
Sep-
08
Apr-
09
Jun-
10
Nov
-10
May
-11
Aug-
12
May
-13
Dec
-13
Mar
-15
100
1000
10000
≥100 m
0-50 m
Aver
age
infa
una
per s
quar
e m
etre
Venus Bay OutfallInfauna abundance, 2004-2015
Feb-
04
May
-05
Mar
-06
Sep-
08
Apr-
09
Jun-
10
Nov
-10
May
-11
Aug-
12
May
-13
Dec
-13
Mar
-15
100
1000
10000
≥100 m
0-50 m
Aver
age
infa
una
per s
quar
e m
etre
Outfallcommissioned
Venus Bay OutfallInfauna abundance, 2010-2015
200 m 100 m 50 m Outfall 50 m 100 m 200 m Mixing Zone Mixing Zone Reference
North South
0
100
200
300
400
500
600
Median operational 80 percentile (reference)20 percentile (reference)
Infa
una
per s
quar
e m
etre
Venus Bay OutfallOphiuroid abundance, 2010-2015
200 m 100 m 50 m 50 m 100 m 200 m Mixing Zone Mixing Zone
North Outfall South
0
5
10
15
20
25
30
35
40
45Median operational 20 percentile (reference)80 percentile (reference)
Oph
iuro
ids p
er sq
uare
met
re
Thanks to
City West Water
South Gippsland Water
Murray Goulburn Co-operative
Infauna Data (Lynda Avery)