Summary of test results from Belmore Basin sewage seep

Crown Lands advised the EPA on 4 February that the seep had stopped after repairs were made to the sewerage system servicing the Fisherman’s Coop Building.

The EPA carried out daily water monitoring at seven locations in Belmore Basin from 20–26 January and will conduct further monitoring at a number of the sample sites until late February.

EPA water monitoring design

The samples taken during the monitoring period were analysed for faecal coliforms, enterococci and ammonia. Ammonia is an indicator of raw sewage in the water, while faecal coliforms and enterococci are bacterial indicators for sewage contamination. The EPA also reviewed rainfall data from the Bureau of Meteorology weather station at Bellambi.

When faecal coliform levels are above 150 cfu/100ml and/or enterococci levels exceed 35 cfu/100ml, a waterway is defined as a ‘waterway to be affected’ for primary contact recreation. This means the waterway is not recommended for recreational use. (Note: ‘cfu/100ml’ refers to ‘colony-forming units per 100ml’ and is a measure of the number of bacteria in 100ml of water.)

The National Health and Medical Research Council generally advocates the use of enterococci rather than faecal coliforms as the single preferred indicator organism to detect the presence of sewage in marine waters. However, the EPA monitored for both faecal coliforms and enterococci to ensure a thorough sampling program was undertaken.

EPA monitoring test results

The EPA’s test results show that the effect on water quality from the discharge was localised adjacent to the sandstone wall where the sewage seep was occurring.

However, some raised enterococci readings were recorded at times in locations away from the sewage seep. The maximum reading was 800 cfu/100ml. Levels of faecal coliform were also elevated in some samples, but the results still support the evidence that the sewage seep was minor. Combined with the rainfall data collected over the same period, these results suggest that stormwater runoff may have also been a key factor influencing water quality in the basin at the time of testing.

Results of sampling conducted since the date the seep was fixed continue to show low levels of enterococci in the vicinity of the seep.

Faecal coliform levels recorded during EPA sampling (cfu/100ml)

 

Sampling locations

Rain
0900 hrs
(mm)

 

1

2

3

4

5

6

7

20/01/2014

3600

130

690

2100

120

430

3600

4.6

21/01/2014

120

280

250

1200

350

680

1200

7.4

22/01/2014

620

2

42

14

18

18

600

0.2

23/01/2014

280

38

170

300

52

310

1000

5.6

24/01/2014

240

10

12

440

130

300

8

0

25/01/2014

840

50

3

3

16

40

230

4.2

26/01/2014

2

3

24

4

54

30

200

2

30/01/2014

34

n/a

n/a

2

n/a

n/a

80

0

03/02/2014

92

n/a

n/a

28

n/a

n/a

150

0

05/02/2014

2

n/a

n/a

5

n/a

n/a

7

2.2

Enterococci levels recorded during EPA sampling (cfu/100ml)

 

Sampling locations

Rain
0900 hrs
(mm)

 

1

2

3

4

5

6

7

20/01/2014

28

27

280

690

140

280

800

4.6

21/01/2014

10

25

43

430

40

62

220

7.4

22/01/2014

2

2

2

14

2

8

150

0.2

23/01/2014

18

12

12

300

40

180

450

5.6

24/01/2014

14

2

2

440

60

60

20

0

25/01/2014

18

14

2

3

10

20

74

4.2

26/01/2014

6

2

16

4

14

18

58

2

30/01/2014

2

n/a

n/a

2

n/a

n/a

28

0

03/02/2014

2

n/a

n/a

28

n/a

n/a

12

0

05/02/2014

2

n/a

n/a

8

n/a

n/a

6

2.2

Ammonia levels recorded during EPA sampling (mg/L)

 

Sampling locations

Rain
0900 hrs
(mm)

 

1

2

3

4

5

6

7

20/01/2014

0.2

0.12

0.05

0.21

0.09

0.08

0.12

4.6

21/01/2014

0.09

0.07

0.08

0.03

0.05

0.01

0.1

7.4

22/01/2014

n/a

n/a

n/a

n/a

n/a

n/a

n/a

0.2

23/01/2014

n/a

n/a

n/a

n/a

n/a

n/a

n/a

5.6

24/01/2014

n/a

n/a

n/a

n/a

n/a

n/a

n/a

0

25/01/2014

n/a

n/a

n/a

n/a

n/a

n/a

n/a

4.2

26/01/2014

n/a

n/a

n/a

n/a

n/a

n/a

n/a

4.2

30/01/2014

0.15

0.14

0.14

0.16

0.15

0.16

0.19

2

03/02/2014

n/a

n/a

n/a

n/a

n/a

n/a

n/a

0

05/02/2014

0.6

n/a

n/a

0.3

n/a

n/a

0.3

2.2

The image below shows the EPA sampling locations.

EPA sampling locations of Belmore Basin

EPA sampling locations

Further investigation

The EPA will now thoroughly investigate the incident and has requested a detailed incident report from Crown Lands.

The EPA and Wollongong City Council will conduct monitoring in the area until late February to assess the effectiveness of measures put in place to stop the seep.

Where can I get more information?

For a copy of the full test results, contact the EPA at (02) 4224 4100 or epa.illawarra@epa.nsw.gov.au.

Further information on water quality monitoring can be obtained from the Office of Environment and Heritage Beachwatch website.

 

Page last updated