TURIMETTA HEAD OUTFALL

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Monitoring Results

Indicator Bacteria

Regular monitoring of faecal coliforms at beaches in the vicinity of Warriewood outfall is undertaken by Beachwatch (EPA 1998).

Biological Communities  

General findings (not necessarily related to outfall):

• most fish were present in similar abundance at the outfall site compared to reference reefs (at Barrenjoey Headland and Inscription Point).

• One species, rock cale (Crinodus lophodon), appeared to be present in lower numbers at the outfall.

Methods: 

Lincoln Smith (1985) a carried out a one-off sampling survey of rocky reef fish. 

 Found that sewage effluent:

• Increase the species richness of sponge types compared to control locations.

But had no effect on:

• the diversity or abundance of kelp, algal or faunal assemblages (compared to control locations)

• the cover or numbers of individual sponges, including the two most common species Psammopemma sp. and Tedania sp.

Methods:               

Roberts and Scanes (in press) investigated the macrobenthic assemblages living on hard substrata in shallow water kelp forests. The macrobenthic assemblages were sampled at six locations (Norah Head, North Avoca, Winnie Bay, Bangalley Head, Warriewood and Cape Banks), three of which (Norah Head, Winnie Bay and Warriewood) have ocean outfalls and the other three sites were treated as controls. At each location two randomly selected sites were sampled in approximately 6-10m water depth. At each site SCUBA divers estimated abundance of macrobenthos by recording the number and percentage cover of organisms (using the point-intersect method) in 5 randomly placed quadrats (27cm²).

Found no effect on:

• body condition, wet weight, percentage dry weight, lipid dry weight or mortality of oysters at Norah Head, Warriewood and Winnie Bay outfalls.

• trace metal levels in oysters with respect to outfall and control sites with the exception of selenium

• extractable organic halogens (EOX) in oysters between outfall and control sites.

• organochlorine pesticides in oysters deployed at the outfall sites.

General findings (not necessarily related to outfalls):

• the selenium levels found at the outfall sites were found to be similar to other EPA oyster studies and these putative outfall effects require further analysis.

Methods:

Transplanted Sydney rock oysters (Saccostrea commercialis) were also deployed at the same sites as those described by McNeill (1993).

Outfall Site

Faecal Coliform

Sponge

Outfall Site

Ulva

Outfall Site

Rock Oysters

Turimetta Head

(Turi_7) Last updated May 2000