Water

Publications

River Health in the New South Wales Lower North Coast, Hunter and Central Coast Catchments

A report of AusRivAS assessments 1994 - 1999
Grant Hose and Eren Turak
Environment Protection Agency, 2004
ISBN 0 642 55099 9 ISSN 1447-1280

Ourimbah Creek

Tugg502 - Ourimbah Creek at Freeway

Site Condition Summary

This site was on Ourimbah Creek, just downstream of its confluence with Canada Drop Down Creek, and where it passes under the Sydney-Newcastle freeway. Because of its proximity, this site received runoff from the freeway, as well as rural areas in the Ourimbah Creek catchment.

The riparian zone had been disturbed by the freeway construction. The riparian vegetation consisted mostly of exotic species, there was some erosion of and rubbish on the banks. The instream habitat was impacted by siltation and rubbish.

Concentrations of oxidised nitrogen (NOx) were higher than expected for a stream of this type. pH was low on both sampling occasions which might be expected for streams of this type. Visual assessments noted high turbidity.

Single season AusRivAS assessments indicated a rich fauna (O/E-Taxa values 0.94, 1.06). However, the combined season model indicated some degree of impairment (O/E-Taxa value 0.76).

Location Map

Location Map

Location Details
Map Name Wyong 9131-2-N
Map Zone 56
Map Scale 1:25000
Easting 349100
Northing 6310400
Distance from source (m) 23295
Elevation (m asl) 15
Average Annual Rainfall (mm) 1100

Sampling Data and Assessments

Single Season Assessments

Edge
  Autumn '97 Spring '97
  3-Jun-97 12-Nov-97
O/E Taxa 0.94 1.06
Band A A
O/E SIGNAL 1.09 1.05

Riffle

Combined Season Assessments

Edge
Seasons AUT97SPR97
Model Eastern
O/E Taxa 0.76
Band B
O/E SIGNAL 1.08

Riffle

Taxa Collected

X= Taxa Predicted & Collected, O = Taxa Predicted & NOT Collected, + = Taxa Collected & NOT Predicted

Edge
      Autumn '97 Spring '97
Phylum Class/Order Family 3-Jun-97 12-Nov-97
Annelida Hirudinea Erpobdellidae +  
Annelida Oligochaeta   + +
Arachnida Hydracarina   X X
Crustacea Cladocera Cladocera   +
Crustacea Decapoda Atyidae X X
Crustacea Ostracoda   O  
Insecta Coleoptera Dytiscidae X X
Insecta Coleoptera Elmidae   +
Insecta Coleoptera Hydraenidae X +
Insecta Coleoptera Hydrophilidae O O
Insecta Coleoptera Noteridae +  
Insecta Coleoptera Scirtidae X X
Insecta Coleoptera Staphylinidae   +
Insecta Collembola     +
Insecta Diptera Chironominae X X
Insecta Diptera Culicidae   X
Insecta Diptera Orthocladiinae O  
Insecta Diptera Tanypodinae X X
Insecta Ephemeroptera Baetidae +  
Insecta Ephemeroptera Caenidae   +
Insecta Ephemeroptera Leptophlebiidae X X
Insecta Hemiptera Corixidae +  
Insecta Hemiptera Gerridae O O
Insecta Hemiptera Hydrometridae X X
Insecta Hemiptera Mesoveliidae O  
Insecta Hemiptera Veliidae X X
Insecta Megaloptera Sialidae +  
Insecta Odonata Aeshnidae   +
Insecta Odonata Coenagrionidae +  
Insecta Odonata Isostictidae +  
Insecta Odonata Synlestidae   +
Insecta Trichoptera Atriplectididae +  
Insecta Trichoptera Calamoceratidae + +
Insecta Trichoptera Leptoceridae X X
Insecta Trichoptera Odontoceridae + +

Riffle

Water Quality Data

  Autumn '97 Spring '97
  3-Jun-97 12-Nov-97
Water Temperature (°C) 11.2 18.7
Conductivity (µS/cm) 221 136
Dissolved Oxygen (mg/L) 7.9 4.9
Alkalinity (mg CaCO3 /L) 14 16
pH 6.27 6.54
Turbidity (NTU) 9.5 5.2
Low Total Phosphorus (µg/L) <12 26
Free Reactive Phosphorus (µg/L)    
NOx Nitrogen (µg/L) 540 260
Total Kjeldahl Nitrogen (mg/L) <0.3 0.41
Ammonia (µg/L)    
Nitrate (µg/L)    
Nitrite (µg/L)    

Key

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