LANE COVE RIVER
CATCHMENT MANAGEMENT COMMITTEE
Water Quality Inventory
November, 1998.
A technical report as companion to a CD-ROM database and 1:10 000 orthophoto map / overlay series.
Researched and written by Dugal D McFarlane.
Lane Cove River Catchment
Water Quality Inventory
Lane Cove River Catchment Management Committee
November, 1998
The author and Lane Cove River Catchment Management Committee would like to thank the following for their assistance and participation in this project;
Thanks also go to; Peter Mitchell, Julian Long, Duncan Veal, the CMC coordinators and Heidi Wagstaff.
Special thanks go to Erika Klimpsch and Rebecca Nicolson for their help and support throughout this project.
This technical report accompanies a 1:10 000 orthophotomap and overlay series and CD-ROM database developed for the Lane Cove River Catchment Management Committee. It gathers together information on water quality in the catchment from a wide array of sources from 1989 to 1998 and assembles this information in a single repository which is both readily accessible to the committee and easily understandable.
This report outlines the way in which the data was collected, how it was managed and what it all means. It divides the Lane Cove catchment up into its sub-catchments and ranks each on the basis of its water quality as stipulated by the ANZECC guidelines (1992). It identifies possible sources of pollution, identifies gaps in the current data, suggests a suitably efficient and effective water quality monitoring regimen for the entire catchment and proposes recommendations for the improvement of water quality in the catchment.
Appendices are provided giving summaries of water quality sites, the location of sewage and stormwater outlets, pollution control devices and other pollution sources. Separate sections give details of relevant contacts and publications involved with water quality in the catchment.
It is hoped that the nomenclature applied to the catchment is adopted by all constituent councils as a convenient and consistent reference. LCRCMC also anticipates that the CD-ROM data base including bibliographies, contacts lists, water quality and rainfall databases is used, updated and appended as a working and dynamic tool so that information is kept updated and transferred in a uniform format.
In the future, the LCRCMC may place such information on the internet and may periodically issue information updates via, disk, e-mail or through the web site.
Files used in CD-ROM database for water quality issues. v
Acronyms and Abbreviations vii
Glossary vii
1.2 Guide to the CD-ROM which accompanies this report.
1.4 Methodology of the collection and treatment of data.
1.4.2 Water Quality
1.4.3 Sewerage Reticulation System
1.4.4 Drainage Reticulation System
1.4.5 Pollution Sources
1.4.6 Landuse Information
1.4.7 References and Contacts
2.0 Liaison
3 Lane Cove River 1 17
5 Lane Cove River 2 19
7 Lane Cove River 3 21
9 Lane Cove River 4 23
11 Lane Cove River 5 26
30 Eastwood 46
4.0 Summary and Overall Recommendations
4.1.1 Impacts of sewerage
4.1.2 Impacts of nutrients
4.1.3 Water quality monitoring
4.2 Suggested sampling regimen for Lane Cove catchment
4.4 Considerations
Table 1: Orthophotomaps covering Lane Cove catchment
Table 2: Land Use zoning’s for Lane Cove catchment
Table 3: Land Use in Lane Cove Catchment.
Table 4: EPA water quality assessment categories
Table 5: Reliability ratings for sources in Lane Cove catchment.
Table 6: Minimum water quality parameters to be used in testing waters in Lane Cove catchment.
Files used in CD-ROM database for water quality issues.
Filenames used are for WindowsÔ based applications. Macintosh applications will have the same filename but a different extension.
wqreport.doc Water Quality report excluding the sub-catchment reports (Word)
catch_01.doc - catch_43.doc Water quality sub-catchment reports (Word).
sbcatch.xls Breif summary of all sub-catchments including; name, landuse, creeks, number of overflows, water quality sampling points, PCDs etc. (Excel)
pcds.xls Location and description of pollution control devices (Excel)
epa.xls Location and details of EPA licensed dischargers (Excel)
sewer.xls Details of all sewerage overflows including location and SWC reference number (Excel).
wqsites.xls Description of all water quality sites (Excel)
AWT tab: ‘conversion of LCRCMC and AWT water quality sites.
metsites.doc Details of rainfall stations in the catchment.
r01_rain.xlb - r14_rain.xlb Rainfall data since 1989 (Excel)
suburbs.xls Suburbs in or partly within the catchment and their AWT or Bureau of Meteorology sites (Excel)
catch_01.xls-catch_43.xls Water quality data for each catchment comprised of each of the sites within the catchment.
watrcont.mdb Contact database for water quality (Access)
watrrefs.mdb Bibliography of water quality material for Lane Cove catchment (Access).
A Catchment Management Act description of LCRCMC
B Map showing catchment and sub-catchment boundaries
C Summary information regarding sub-catchments
D Map showing location of water quality monitoring sites.
E Detailed information on water quality sampling sites
F Rainfall site information
G List of suburbs in catchment with Bureau of Meteorology and AWT rainfall sites.
H Map showing the location of designed sewerage overflows
I Detailed information on designed sewerage overflow points
J Map showing the location of Pollution Control Devices
K Detailed information regarding PCDs
L EPA licensed dischargers information
M Map showing suggested sampling locations within Lane Cove catchment
N Key relating AWT/ Scientific Services water quality sites to those for LCRCMC
O Map showing soil landscapes in Lane Cove catchment
P Map showing acid sulphate soils in Lane Cove catchment
Q Contact List
R Bibliography
ANZECC Australian & New Zealand Environment and Conservation Council
AWT Australian Water Technologies
CD-ROM Compact Disk - Read Only Memory
CMC Catchment Management Committee
DO Dissolved Oxygen
EIS Environmental Impact Statement
FC Faecal coliforms
GIS Geographical Information System
GPT Gross Pollutant Trap
HHC Hunters Hill Council
HSC Hornsby Shire Council
LCC Lane Cove Council
LCRCMC Lane Cove River Catchment Management Committee
NSOOSS Northern Suburbs Ocean Outfall Sewerage System
PCC Parramatta City Council
PCD Pollution Control Device
SPS Sewerage Pumping Station
SWC Sydney Water Corporation
Infiltration: where stormwater leaks into sewerage lines
exfiltration where sewage leaks from sewerage lines
choke where a blockage occurs in a sewerage line due to plant roots
orthophotomap a part visual and part topographic map
To compile and assess all available water quality and river discharge data for the Lane Cove River and estuary to provide comprehensive condition data for the recent past.
1. To provide resource information to land managers to achieve coordinated catchment management.
2. To provide baseline data against which future conditions may be assessed.
3. To identify knowledge gaps and opportunities for achieving the aims.
4. To identify and rank water quality in the sub-catchments.
5. To assist in the location of important pollutant sources.
6. To rationalise and coordinate future data collection across the catchment.
7. To assemble all the available data in a single repository.
1. Assemble water quality sampling results and river discharge data from all published and unpublished sources.
2. Assemble all rainfall records for the catchment.
3. Assess and rank the reliability of all data sources having regard to the methods used and the parties involved.
4. Compile the data is the most meaningful way by matching quality with flow conditions in sub-catchments and / or river segments.
5. Rank sub-catchments and / or river segments on water quality and if possible identify major pollution sources, especially point sources.
6. Identify locations where past sampling has been inadequate.
7. Develop a rational data collection program which can be coordinated between all involved parties which will effectively monitor future flow conditions and water quality.
8. Establish a contact list for all parties presently involved in data collection relevant to this project.
9. Compile a comprehensive bibliography of all relevant reports and other printed resources. Assemble copies of all those resources not presently held by the LCRCMC office.
10. Map existing landuse.
11. Identify and map the location of stormwater outlets where this has been documented and highlight gaps in this knowledge.
1.2 Guide to the CD-ROM which accompanies this report.
The CD-ROM is WindowsÔ 3.11 and Windows 95Ô compatible and requires MS Word v6.0, Excel v5.0 and Access v2.0. This report appears in its entirety on CD-ROM as a Word 6.0 document (WQReport.doc). The CD-ROM also contains three separate databases developed in MicrosoftÔ Access version 2.0. These are;
i) a comprehensive bibliography of all written reference material relevant to water quality in the catchment including references to maps and software;
ii), a contact database listing all relevant persons involved in some way with water quality in the Lane Cove catchment and;
iii) a water quality database providing detailed water quality data, rainfall data and catchment information presented largely as Excel version 5.0 spreadsheets.
A directory of files is included at the beginning of this report.
Instruction on how to operate the CD-ROM database are provided on the inside front cover of the CD.
1.3 Guide to the 1:10,000 orthophotomap and overlay series
This report accompanies a large 1:10,000 scale orthophotomap and a series of overlays. Each map or overlay contains a different ‘theme’ and may be used in isolation or in conjunction with other overlays to gain a more thorough understanding of the Lane Cove catchment. Details of the overlays are provided below;
Base Map: 1:10 000 orthophotomap:
| Map Name | Number | Map Name | Number |
| Epping | U0060 | Parramatta | U0052 |
| Pymble | U0960 | Gladesville | U0952 |
| Mt. Colah | U0967 |
Table 1: Orthophotomaps covering Lane Cove catchment
The catchment boundary for Lane Cove catchment is shown in red. This boundary is topographical and relates to the water shed but for convenience is often aligned with major roads such as the Pacific highway, Pennant Hills Rd, Marsden Rd and Victoria Rd.
The base map also shows the council boundaries in blue and the sub-catchment boundaries in purple. The location of rainfall stations are shown by large blue dots.
Land Use
The land use overlay coincides with Local Environment Plan maps (LEPs) provided by councils. The land uses shown are;
| Green: | Open space; parks, golf courses, bushland, reserves |
| Pink: | Residential; houses, townhouses, villas, units |
| Blue: | Business, shops, service stations, malls, offices |
| Purple: | Industrial: light - heavy industry, manufacturing, technology parks |
| Yellow: | schools, universities, churches, council depots, utilities, commonwealth government land. |
| Red: | Proposed or existing reservations for county roads (eg M2). |
Table 2: Land Use zoning’s for Lane Cove catchment
The total area and proportion of the land use in each sub-catchment can be seen in the sub-catchment reports (section 2.0), Appendix C and in the CD-ROM database.
Water Quality
This overlay shows the location of water quality sampling points (Ä 001 - Ä 068) since at least 1989 and a reference number which corresponds to this report (Appendix E) and the CD-ROM database. Some points have been sampled by many different organisations over time and are identified in the CD-ROM database.
Also shown (by brown dots) are the location and reference of pollution control devices (PCDs) D001 - D026 (Appendices J, K) and rainfall stations (Y R01 - R14) (Appendix D, F).
Sewerage and Stormwater
This overlay presents indexes of all known sewerage overflow points in the catchment on fluorescent orange dots (see also Appendix H, I). It also shows the approximate location of sewerage mains, sub-mains and carriers (red lines) and the approximate location of the north side storage tunnel (orange line).
The location of stormwater outlets is shown by fluorescent yellow dots. A number written on the dot represents the number of outlets covered by the area of the dot. A blank dot means that only one outlet is present.
Blue dots with the numbers LD001 - LD003 show the location of EPA licences dischargers (Appendix L).
Bushland Inventory
Other overlays are available which detail;
Details of these overlays can be found in the accompanying volume to this report ‘Lane Cove River Catchment - Bushland Inventory (Klimpsch, 1998)’.
1.4 Introduction to the Lane Cove Catchment
Lane Cove River Catchment is located within the metropolitan area of Sydney’s north shore. The catchment comprises low undulating terrain situated on predominantly sandstone geology.
The catchment is highly varied and contains a number of land uses. Though largely residential there are large tracts of open space (including a number of golf courses and the Lane Cove National Park), business and industry. Table 3 (below) shows the proportion of land use in the catchment.
Landuse |
Area (ha.) |
Area (km2) |
% of catchment |
Open Space |
1974 |
19.74 |
24.5 |
Residential |
4709 |
47.09 |
58.3 |
Business |
130 |
1.3 |
1.6 |
Industrial |
202 |
2.0 |
2.5 |
Special Uses |
844 |
8.4 |
10.5 |
Special Reservation |
215 |
2.2 |
2.7 |
Total |
8074 |
80.74 |
100 |
Table 3: Land Use in Lane Cove Catchment.
A map of the catchment can be seen in appendix B and a written description of the boundaries in appendix A.
Current issues in the catchment are concerned with infill developments and the loads that are placed on the ageing sewerage system causing sewage to frequently overflow into waterways. In addition, phosphorus and nitrogen loadings into creeks combined with low flow and low oxygen conditions is providing eutrophic conditions suitable for algal blooms.
1.4 Methodology of the collection and treatment of data.
Daily rainfall data was obtained from the Bureau of Meteorology on disk at low cost. Other sources used were Lane Cove National Park, North Ryde Golf Course, Pennant Hills Golf Course, and the CSIRO laboratories at East Ryde. Stations were chosen to provide a good coverage across the catchment.
The reliability of rainfall data may be assessed as;
More stations are maintained by Australian Water Technologies within the catchment (see Appendix G) and are available at high cost. With the exception of a gap in the north-west of the catchment ( Thornleigh, Normanhurst area) rainfall information is thorough.
The purpose of collecting rainfall data was to match it with water quality data to determine the effect of flow on the catchment (see section 1.1.3 point 1). Wet weather water quality will appear to be better because it dilutes pollutants so they are detected as being low where the total quantity is much higher than would normally occur in ‘dry’ conditions due to run-off carrying the extra load.
Rainfall was matched with water quality where a specific date was given for a sample. The closest rainfall station to the sample site was used, or the average of the two closest. A ‘wet ‘ weather sample was defined as greater than 10.0 mm of rain on the day of sampling and/or more than 10.0 mm in the preceding 48 hours. Recovery (‘REC’ in the database) periods were treated as wet periods and were defined as less than 10.0 mm of rain in the 48 hour period after the last rain. Dry periods are any other time.
Each council in the catchment was asked to provide the names, sizes and boundaries of the sub-catchments on their land. It was important for LCRCMC to establish a consistent system of naming and identifying sub-catchments for management purposes. Where supplied, the names of the sub-catchments used by council were retained and additional names were chosen based on (i) the stream(s) in the catchment, (ii) the landuse or (iii) the topographic location of a creek. Each of the 43 sub-catchments were numbered systematically from the headwaters in Thornleigh down the eastern side of Lane Cove River, then the western side and finally Hunters Hill. Appendix B is a key map showing their location. A written description of the Lane Cove River Catchment area is provided in Appendix A.
Water quality data was collected from; Lane Cove Council, Hunters Hill Council, Ryde City Council, Parramatta City Council, Hornsby Shire Council, Ku-ring-gai Municipal Council, Willoughby City Council, Australian Water Technologies, Sydney Water Corporation, Streamwatch and Harbourwatch.
Data was entered into a standardised spreadsheet (catch_01.xls - catch_43.xls) and all measurements were standardised to SI units (eg. parts per million (ppm) and µg / L were converted to mg / L) for comparison to ANZECC water quality guidelines.
Where a specific date was given for a particular sample, rainfall data for that day and the preceding 48 hours was matched to that day to determine whether the sample was taken in the ‘wet’ or ‘dry’ ( see section1.4.1 above for details).
ANZECC Water Quality Guidelines
All the water quality sites in each sub catchment were grouped and analysed on a sub-catchment basis by comparing the water quality parameters over the history of monitoring at that site with the ‘Australian Water Quality guidelines for fresh and marine waters, 1992’ produced by the Australian & New Zealand Environment and Conservation Council (ANZECC). Water quality was compared to a range of categories of protection provided by ANZECC which provide protection from pollution at various levels based on community values. These levels were for the protection of;
Aquatic ecosystems :
‘to protect biological diversity and maintain
ecological processes and systems’. These guidelines
are the most stringent and generally ensure that other
related environmental values are protected.
Human consumers:
‘Minimal risk concentrations in the water required
to protect consumers from toxicants which may accumulate
in the tissue of fish, crustacea and shellfish, either
directly from the water or by biomagnification in the
food chain’.
Water Associated
Wildlife: Wildlife include non-fish vertebrates and
are generally protected by guidelines for aquatic
ecosystems but allow for higher levels of suspended
solids which ‘muddy’ the waters. These
guidelines factor in biomagnification of pollutants in
the food chain.
Visual Amenity: These
waters are used for aesthetics only and allow for a wider
pH range and greater chlorophyll-A (plant and algae)
concentrations. They are designed to protect diversity of
aquatic plants.
Primary contact: ‘Waters
used for swimming, bathing and other direct water-contact
sports’. Ingestion of water is very likely so low
faecal coliform levels are specified as is greater visual
clarity (reduced dissolved solids).
Secondary contact: Activities
such as boating and fishing where the risk of ingestion
is lower. ‘Since there is less body contact with the
water, the microbiological guidelines can be lower
(except in the case of taking shellfish from the water
body).Whilst not all the values will be applicable in the catchment, they are included as an indication of the potential for future improvement in water quality in the catchment.
Every parameter value measured was compared to the ANZECC guidelines (where they were available) for each of the six categories above and rated as either ‘PASS’ or ‘FAIL’.
Since Lane Cove River Catchment is highly urbanised, and there is very little historical water quality data, it is difficult to assess what the original condition of the water was. ANZECC guidelines are very useful in assessing water quality in a general sense and are based on a variety of Australian waterbodies, but it must be remembered that the natural ecology of each stream in any catchment may vary markedly. For example, areas on Hawkesbury sandstone are naturally acidic, so pH levels within the guidelines may not reflect the original nature of the stream. Likewise, some streams are naturally turbid or muddy looking and efforts to raise water quality to a point where the stream is crystal clear may be placing unrealistic and unattainable targets on that stream.
With this in mind, the levels of protection stated in the sub-catchment reports are based purely on the ANZECC guidelines. Whilst every care has been taken to ensure that the information presented is accurate, this report is only a guide and values may not be a positive reflection of water quality because;
This index was used to assess the collective water quality of each sub-catchment as a whole to each other in order to prioritise management options. It is prudent to warn that the use of such an index may not reflect the true ‘health’ of a creek or stream because;
The Water Quality Index used in this report was based on the percentage of ‘passes’ for each water quality parameter compared to the number of parameters measured for each date averaged over the entire history of the site. The pre-existing ANZECC guidelines were used as these already incorporated community values.
Each value category was assigned a colour to easily assess water quality on a catchment level. These categories were adopted from the pre-existing ‘Proposed Interim Environmental Objectives for NSW waters - 1997’ produced by the EPA to maintain consistency. The colours were;
Green: |
meets selected criteria in over 75% of samples |
Yellow: |
meets selected criteria in 50 - 75% of samples |
Orange: |
meets selected criteria in 25 - 50% of samples |
Red: |
meets selected criteria in less than 25% of samples |
White: |
one or more key criteria not available for assessment |
Table 4: EPA water quality assessment categories
The water quality database is a comprehensive database listing water quality details for each site measured in Lane Cove catchment since 1989. It uses a number of sources from councils, private consultancies and schools involved in the Streamwatch and Harbourwatch programmes. In line with the objectives of the brief for the water quality inventory and in order to distinguish data gathered for research purposes from data gathered primarily for educational purposes, a reliability score has been provided. However, it must be noted that in many cases there has been no water quality monitoring for the catchment whatsoever and thus this data is invaluable to an overall understanding of the condition of the Lane Cove River catchment.
For all sources used in the compilation of this database, a standard format has been adopted. It is for this reason that not all parameters will have been filled. The reasons for this include a lack of resources (including funding) and time or a feeling that such a parameter is not required to reach the goal of the sampling programme. In some cases this may be to determine the cause of a noted event or to reach a level of participation and understanding appropriate to the audience (such as with the Streamwatch programme). In either case, another function of this inventory is to identify which parameters will tell us most about the condition of water quality in the catchment for least cost. In addition to this an effective catchment wide sampling regimen will be recommended.
Below is a brief explanation of the column headings found in the database. With regard to the parameters which appear in the database, an explanation of their ecological significance, how and why they are measured and the effort involved in their collection is also included. This will help to establish which parameters are most needed to be sampled and which if required could be omitted.
Comparison is made to the 1992 ANZECC guidelines for fresh and marine waters, the level of protection (eg. visual, primary contact recreation) being stated. These guidelines are the most suitable for Australian waters at present but currently under review is a revised, expanded and thoroughly comprehensive 1998 edition
Explanatory notes for columns used in the water quality database
No.: catchment reference number
Source: The name of the body which collected the sample. This may be a council, a private consultant or a school.
Reliability: This is determined by giving each source a rating based on their experience at water quality data collection, analysis and interpretation.
| Rating 1 - high | Rating 2 - moderate | Rating 3 - low |
| Private consultants (eg. Sinclair Knight Mertz, AWT / Scientific Services. SWC, John Laxton and Assoc. Pty. Ltd. Are specialists at water quality monitoring, have considerable experience and often have their own fully equipped laboratories. | Councils (they often
collect some data using instruments but will send wet
samples to NATA approved labs. for analysis. The
transport and storage of these samples is vital. Harbourwatch, Universities |
Streamwatch groups such as schools, study centres and other educational institutions (not universities). The emphasis is on learning rather than accuracy and background knowledge is very limited. Usually only one off sampling occurs rather than a regimen. |
Table 5: Reliability ratings for sources in Lane Cove catchment.
Where a number of sites and groups are involved in a sub catchment, the reliability score is simply the average of all the contributors of information for that site. For sub-catchment reports, reliability scores close to one (1) may be regarded with good confidence whilst those close to three (3) mean that the data should be treated with scepticism and caution. Values equal to three mean that no data was recorded.
Description of column headings in the Water Quality Database Spreadsheets.
Site no.: Reference is given to the original source and to the LCRCMC
Map: The number of the NSW orthophotomap on which the grid reference is based. This will ultimately be the large catchment map.
Eastings and Northings: grid reference given to locate the exact sample site on the map.
Date: Date on which the sample was taken
Rainfall: By using rainfall from the nearest weather station or by interpolating likely rainfall from two nearby weather stations, an approximate rainfall will be determined for the sample site.
Area of catchment: Area in hectares (ha) as determined from catchment maps. This item may be used to calculate stream flow measurements.
Flow: Flow in ML(megalitres) per day. This information was not available. NF = no flow.
Wet/Dry: Wet / Dry / Recovery. A basic summary of weather conditions given; Wet = > 10mm in preceding 48 hrs, Dry = <10mm in preceding 48 hrs, Recovery = <10mm in 48 hr period after last wet period.
Weather: Observational comments on weather as supplied in source comments as applicable.
Tide: H = high, L = Low, VH = very high (king tide), VL = very low (ebb tide), where appropriate (basically downstream of the Fullers Bridge weir), otherwise N/A.
WQIndex: A very approximate method used to compare each site and sub-catchment with each other taking into account all parameters tested at that site and whether or not it met the ANZECC guidelines.
Temp. : (oC) Water temperature at time of sampling. This is important because temperature affects the types of chemical constituents available to organisms in the water column such as oxygen saturation. Any laboratory tests on water samples should be conducted at the temperature at which the sample was collected. Water temperature also signified stratification in a water body which may indicate stagnation.
pH: (pH units) pH affects the chemical and biological balance of waters. Natural freshwater’s range in pH from 6.0 to 9.0 and salt waters from 8.0 to 8.3, the smaller range in seawater is due to the homogeneous nature of such a large water body. For freshwaters, this range is normal and, in the Sydney region, the pH of freshwaters is largely affected by the underlying geology. Hawkesbury sandstone is much more acidic (lower pH) than Wianamatta shale. Changes in the pH of waters can directly affect the mortality of fish eggs, larvae and macroinvertebrates and in a general sense, changes in the pH will alter the solubility and so the availability of heavy metal compounds and other soluble pollutants.
Faecal coliforms: (cfu (colony forming units) / 100 mL). Faecal coliforms are indicator organisms which are readily identified and counted and closely associated with pathogens such as Escherichia coli, Salmonella, Shigella Pseudomonas, Streptococcus, Staphylococcus, Legionella, hepatitis, viruses and parasites. Aliquots (portions) of water sample are incubated in ideal conditions for microbial growth for a set period of time and the number of growths or colony forming units (cfu) are counted.
DO: Dissolved oxygen (mg / L). Aquatic organisms, both plants and animals require oxygen dissolved in the water to survive. Dissolved oxygen is also required for chemical processes in the water such as the oxidation of many chemical compounds. Dissolved oxygen is controlled in the Lane Cove River catchment by tidal flushing, vertical mixing of the water column and by the amount of oxygen which is produced and consumed by the living organisms in the water. Polluted creeks will tend to reduce the dissolved oxygen level because the extra load introduced into the waterway will result in increased levels of micro-organisms such as bacteria and an increased use of oxygen by these organisms in the breakdown of pollutants. At lower temperatures, dissolved oxygen becomes less readily available.
% Sat.: Dissolved oxygen (% saturation of the water) This is often more easily measured using an electronic probe and is quoted separately. A conversion from mg/L to % saturation of water exposed to water saturated air is possible through a complex calculation. Its significance however is the same as DO (mg / L).
BOD5: Biological Oxygen Demand (mg / L). BOD5 is the amount of dissolved oxygen consumed by micro-organisms in the breakdown of organic pollutants such as sewage in the water. It is referred to as BOD5 because during testing, the water sample is thoroughly aerated by shaking. It is then halved with one sub-sample incubated for five days in total darkness before testing and the other tested immediately. The difference of the dissolved oxygen is the BOD5 and reflects the microbial activity since micro-organisms in a polluted water will use more oxygen than those in a clean one. Oxygen demand in clean waters in roughly less than 2 mg / L while polluted waters demand oxygen in the range of 100 - 300 mg / L.
Turbidity: (ntu - nephelometric turbidity units). Turbidity measures the optical properties of the water. High turbidity means that the water is very murky. This results in low light penetration for the growth of aquatic plants (and the run on effects of low DO and unsuitable habitat for aquatic fauna) and poor aesthetics. The source of turbidity is generally organic matter and soil and mineral particles suspended in the water column.
Diss. solids: (mg / L). Dissolved solids measures the dry weight of solid matter such as detritus, silt, clay, organic matter and plankton suspended in the water which cannot be collected through filtration and may also include sewage and other human waste.
Total P: Total phosphorus (mg / L). This test measures all available forms of phosphorus such as orthophosphate, soluble and insoluble condensed phosphates, and organic and inorganic phosphates by converting all these forms to orthophosphate which is readily measured. It is important to measure phosphorus because soils in the Sydney region including those of the Lane Cove River are naturally low in phosphorus and the use of fertilisers in urban areas introduces excessive amounts of the element which inhibit the growth of natural riparian plant species and promotes the growth of introduced plants in our stream . This in turn changes the type of food which is available to animals in the stream and consequently brings about a significant change in the nature of our streams.
Total N: Total nitrogen (mg / L). Total nitrogen combines all forms of nitrogen (nitrite-NO2- - N, nitrate-NO3--N and ammonia-NH3) Nitrogen is another component of artificial fertilises and a nutrient which occurs naturally in low levels in Australian soils. High levels therefore provide an advantage for weed species to colonise an area.
NOx: Nitrates (mg / L). Nitrates come in many different forms and are not covered extensively be the ANZECC guidelines.
Conductivity: (m s / cm). Conductivity is measured electronically and detects the levels of dissolved ionic compounds in the water by passing an electrical current through the sample. It is important to measure the ionic composition of the water because the level of ions in the water can change the osmotic balance and affect rates of absorption and solubility of gases. The temperature will affect conductivity readings and is often quoted at 25oC.
Salinity: (mg / L) can be ppt (parts per thousand) and a conversion is necessary. The effects of salinity are similar to those discussed for conductivity though salinity will affect the type of vegetation which can grow in the waterway and the type of organisms.
Ammonia: (mg / L). The presence of ammonia is largely dependent on the pH and DO concentration since it is largely unstable and unless measured of frozen within 2 hours of collection will produce highly variable results. Ammonia in waterways come from the decomposition of organic matter such as sewage and industrial effluent. It can become toxic to aquatic plants especially in very alkaline conditions with low DO.
Chl. A: (mg / L). Phytoplankton and algae (such as toxic blue-green algae) often grow in large numbers as the result of eutrophication. Since they contain the pigment chlorophyll A, measuring this gives an indication of algal biomass.
Other info: Additional information such as other parameters measured, the time the data was collected, and other additional comments are recorded here.
1.4.3 Sewerage Reticulation System
Sewerage maps (1:2000 scale) showing the location of designed overflow points, sewerage pumping stations (SPSs) and the reticulation system (NSOOSS mains, submains carriers and the smaller diameter suburban reticulation system) were supplied by Sydney Water Corporation.
The sewerage system down to carrier level, SPSs and overflow locations was transferred to the larger 1:10 000 sewerage and stormwater overlay and each designed overflow and SPS has been indexed with its SWC reference number (see Appendix I). Information from the SWC Licensing Sewerage Overflow EIS and Ku-ring-gai council records was also recorded on the overlay. At the time of printing, no information regarding sewerage discharge from points not designed to do so was available to LCRCMC. The approximate location of the northside storage tunnel (under construction) was also included.
The reliability of information on the sewerage system as provided by SWC is generally high. However, the sewerage system is old and poor records were kept of pipe and overflow locations when the system was installed. In recent times, SWC and also councils such as RCC and KMC have been auditing their systems as pipe relining and repair operations progress. As a result, the accuracy of data has improved. Also, the recent release of the Licensing Sewerage Overflows EIS has raised the profile of designed overflow locations, so these will be accurate, but there is no information on whether these overflows are active nor if there are active overflows which are not designed to be so.
1.4.4 Drainage Reticulation System
Drainage maps (1:2000) were supplied from KMC, WCC, LCC, RCC and PCC which showed all stormwater inlets from roads and developed areas. No information was supplied by HHC and HSC have limited drainage records. All stormwater outlets in the catchment were mapped on the sewerage and stormwater overlay. Where a high concentration of outlets occurred in a small area, the number of outlets was recorded on the yellow dot marking the location.
As with the sewerage system, the information on council plans is old and may be unreliable. Some councils such as KMC, LCC and RCC are currently auditing their stormwater reticulation systems and have good records of stormwater outlets. Other councils are less reliable and are still dependant on the older plans.
The EPA supplied the CMC with a list of licensed dischargers (offenders of the Clean Waters Act, 1970) (see Appendix L). Other pollution sources (excluding sewer overflows) were identified from council’s anecdotal records. Identification of pollution sources will be outlined in the sub-catchment reports (section 2.0).
Information gained from the EPA may be regarded as extremely reliable since it is under constant review for licensing purposes. Sewer overflows will be more frequently scrutinised following the outcomes of the SWC Licensing Sewerage Overflows EIS.
Each council in the catchment supplied a 1:2000, 1:4000 or 1: 800 scale Local Environment Plan (LEP) map. This information was transferred to the 1: 10000 scale landuse overlay. The six landuse types can be seen in section 1.3 above.
Council LEPs are highly reliable as they are under constant review for development applications. Most councils have GIS based LEPs which can be easily altered and printed out.
The areas occupied by different forms of landuse given on a sub-catchment basis are approximations only. They were gathered by manually counting the number of hectares (1cm grids) occupied by each landuse within each sub-catchment. Verification of these measurements is recommended using a planometer or similar instrument.
References were gathered from material already in the LCRCMC library, the DLWC library and from reports and articles gathered from council, council libraries, and private enterprise in the course of this project. Where possible copies of such reports were assembled and placed in the LCRCMC library. An Access v2.0 database was developed for the purpose of maintaining and searching all references and this is included on the CD-ROM.
A contact list was kept of all persons who helped in the gathering of information or the manipulation and handling of data. An Access v2.0 database was created to assist in the management and searching of these contacts and is also included on the CD-ROM.
The databases are a dynamic product and it is hoped that those included on the CD will be modified and developed to ensure that up to date information regarding water quality in the catchment is maintained.
A contact database has been developed for the CMC using Access v2.0 which details all personal contacts who were involved in the gathering and presentation of the data for this inventory.
The database lists contact and mailing details and also the field of interest, skills and expertise of the contact. This database was developed to be flexible, dynamic and able to be searched from a number of perspectives such as by position held in the organisation, field of interest, expertise or organisation type.
Appendix Q gives a summary of the contacts involved in water quality for the catchment
The following section contains details on each of the 42 main sub-catchments identified in the Lane Cove River catchment area.
The boundaries and nomenclature of each sub-catchment have where possible been taken from those already existing in the council in order to remain consistent with council records. In some cases however, little or no work has been done in identifying catchments within council boundaries.
In these cases the name allotted to the sub-catchment has been as intuitive as possible. Sub-catchments are named on the basis of their constituent stream or the water body they drain into (eg. Brickmakers Creek, Woodford Bay), the topographical portion of the creek (eg, Devlins Creek Upper, Lower and South, Tambourine Bay - East), or the location and type of land use (eg. Ryde Industrial, Lane Cove Industrial, Hunters Hill East). Each sub-catchment has also been numbered for reference purposes with LCRCMC records and with the CD-ROM database.
On occasion there will be differences between the names council has given catchments and those which appear in this report. This is because sub-catchments of the Lane Cove River cross council boundaries and by necessity are divided up into sub-catchment to manage various branches or arms of the creeks.
It is the hope of the LCRCMC that the reference system used in this report is adopted by its constituent councils to maintain a thorough and consistent Total Catchment Management approach.
Each sub-catchment report contains the name of the catchment and its reference number, its constituent councils, its total area and area attributed to open space, residential, business, industry, schools, churches and other special uses and major county road developments.
There is an ionised section showing whether the water is suitable for the different stated uses based on the ANZECC guidelines (1992) (section 1.4.1 ). If the picture is blank then the water is acceptable for that use. If there is a cross in the box, then the water quality is not acceptable for the stated purpose. Note however that this interpretation is guide only as it is based on the average of a wide number of samples, some of which are very old.
Each report will also list the reference number of the rainfall station, water quality monitoring points and pollution control devices. The total number of sewerage discharge points and stormwater outlets are included. A written précis of water quality in the catchment and a relative ranking of the catchments water quality is given out of 42 (1 being the best water quality and 42 being the worst). Finally, a written description of the possible sources of water quality problems in the sub-catchment, identification of knowledge gaps exist and recommendations for catchment management will be presented.
4.0 Summary and Overall Recommendations
The sewerage system
which is gravity fed and runs along the creek lines is old and is
falling into disrepair. There is evidence of leakage from the
sewerage system which is frequently ending up in the creek and
river system for one or many of the following reasons;
It is possible to see that sewerage overflows have an impact over the entire catchment. There is a steady increase in faecal coliform counts from the north of the catchment to the south. This indicates that areas further upstream are cumulatively affecting those down stream. In areas where tidal flushing occurs, the impacts of overflows are not as easily monitored due to a dilution effect but the overall quantity of sewerage is high. For example, it is known that Lane Cove siphon which occurs in Cunninghams Reach (18) discharges huge volumes of overflow in wet weather, yet monitoring understates the severity of the problem.
The condition of the sewerage reticulation system in Lane Cove catchment is poor and has been recognised by SWC. Their current policy is to respond to overflow, blockage and exfiltration events as need arises and immediately fix the problem for two years. This does not address the larger issue of under-capacity which is also recognised as a major problem. The northside storage tunnel will alleviate pressure of overflows from the Lane Cove siphon and four other major overflows in Middle Harbour but pressure will not be relieved any distance up the system.
When the sewerage reticulation system was designed, it was fitted with designed overflow points. Some of these points may be recognised as ‘pop tops’ where the build up of water pressure in the sewerage lines from infiltration in wet weather causes the covers of these access chambers to pop off and release sewage overflow onto land.
Overflows were designed to overflow onto land where there was minimal health risk as opposed to the waterways where sewage could be spread and transferred. In recent times, loads in the sewerage lines have increased causing lids to ‘pop’ more often, the land where designed overflows occur is used more and the system leaks so much that waterways are effected regardless.
An audit of the sewerage system is required which can assess which designed overflows are actually serving their designed purpose, whether there are any designed overflows which are not active and whether there are any overflows not identified from SWC maps which are active. This audit should also try to assess the number and extent of private septic systems and overflows from waterfront properties. From this information it will be possible to tell how effectively the sewerage system is working in each area and it will then be possible to prioritise which areas SWC should address first.
The construction of the northside storage tunnel is intended to release pressure from the sewerage system in Lane Cove. It is important to have the above information on sewer overflows and to begin or continue monitoring of water quality to assess its effectiveness and justify its expense.
The levels of infill development in the catchment are beginning to reduce. One recommendation for the catchment is a systematic upgrade and upsizing of the sewerage reticulation system. It is appreciated that this would be a very expensive operation but it would increase the wet weather carrying capacity of the sewerage system and provide a marked improvement in water quality.
In short the problem of sewerage overflows in the catchment is mechanical and is dictated by financial limitations.
Nutrient levels are frequently in excess of the ANZECC guidelines. The major nutrients of concern are phosphorus and nitrogen since these are naturally low in the soils of Lane Cove catchment. When levels of these nutrients rise, they provide conditions conducive to the growth of exotic weeds, usually garden escapees.
Since streams run in gullies, runoff from paved surfaces in developed parts of the catchment travels to these gullies carrying high levels of nutrients and propogules into the streams. The end result of this process is that riparian (bankside) vegetation consists increasingly of exotic species which ckoke the waterways and reduce flow. Stagnant pools develop and algal species bloom in the nutrient enriched, low flow, low oxygen conditions. In time, the native vegetation is replaced by exotics and the macroinvertebrate and animal species of the creeks diminish and change.
As with sewage pollution, nutrient pollution in Lane Cove catchment deteriorates in a southerly direction. This is partly an additive effect from all the sub-catchments but is also due to the distribution of bushland in the catchment. The headwaters of Lane Cove catchment have a large degree of bushland and therefore the potential water quality of these areas is quite good. It is therefore necessary when targeting improvements in water quality to;
There are many sources of nutrients in the catchment which are potentially contributing to the nutrient loads of the waterways of Lane Cove catchment. Residential areas and household gardens are a very large source but the scale of this land use makes concentrating on easily identifiable point sources first more manageable. Residential areas are best approached through lengthy on-going awareness and the adoption of practices which reduce pollution of this type including the use of products low in phosphorus and nitrogen and using native plant species.
Major point sources of nutrients in the catchment include the golf courses, cemetery and playing field which use high volumes of water and nutrients in maintaining the grass and landscaped areas of their facilities. In many cases, fertilisers are applied as a matter of course rather than as needed so that the excess nutrients in the soil are leached away. Simple soil tests will determine what the level of nutrient required for the plants being grown is. It may be possible to obtain information on the rate of application and type of fertiliser used to assess whether these sites are likely to be large contributors of nutrients to waterways. A small study investigating runoff from open spaces and levels of nutrients in this runoff may be warranted.
These areas are also usually quite large in size. They have the capacity to re-use water which has the advantage of reducing run-off and reducing fertiliser costs because the recycled water is already nutrient enriched. Techniques for harnessing the excess water have been employed in the catchment at Porters creek tip site and the Lofberg Quarry site. Underground agricultural drains care pervious and collect and recycle the leachate from a site. Unfortunately, the installation of such devices is expensive and cannot be justified by land users when no penalty is associated with current practices.
Other techniques for reducing nutrient runoff at sites include the use of swales (grassed channels) at the boundaries of fields to help absorb nutrient enriched water into grassed areas before it enters the stormwater system. It is also possible to use nutrient ‘traps’ such as mini-wetlands to absorb nutrients from the water. Riparian plant species generally require many nutrients and they can soak up alot of nutrient as runoff passes through the wetland. Nutrients are adsorbed to sediments in the wetland and do not pass on into the water course. A mini-wetland is in operation on Plassey St, North Ryde to collect nutrients from the northern suburbs cemetery.
There are a number of similar PCDs scattered across the catchment. When designed for the needs of a specific area, they are very effective. Using the design of one site in another area is not as effective. Often a combination of devices in a catchment will dramatically reduce the catchment’s impact on water quality. Many councils already recognise the value of such devices. However, before more are installed, a study needs to be conducted which evaluates the effectiveness of these PCDs to best utilise their application in other areas of the catchment. This study should also include looking at the land fill leachate from land fill sites including Lofberg Quarry, Porters creek tip site, Gore creek (Lane Cove golf course) and Hodgson Park.
The impact of nutrients on water quality and bushland is greater in areas where there are small skinny areas of bushland separating developed areas from water courses. This is because stormwater outlets occur into bushland and in narrow reserves there is less area of vegetation to collect and ‘filter out’ water borne pollutants such as phosphorus and nitrogen. These areas are more likely to be affected by pollutants and should therefore be looked at first. In this way, it is clear that the health of bushland and water quality are inseparable. The Lane Cove National Park is one such long skinny area with large boundaries, as are the upper reaches of Blackbutt creek.
In short the problem of nutrient pollution in the catchment is lifestyle and is whilst there are structural remedies is addresses by public awareness..
4.1.3 Water quality monitoring
Water quality monitoring has occurred quite extensively over the whole catchment. It has not been conducted at all in Kittys Creek, Eastwood, Tambourine Bay - West, Greenwich -West, Lane Cove industrial, Lane Cove River 6 and Hunters Hill. Inevitably sampling has been done by groups with differing reliabilities and this has resulted in a wide range of tests. However, despite this even the most resource stretched organisations can collect a wide array of information for very little cost. Including the Streamwatch schools, the most informative parameters to be collected in water quality sampling are;
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Table 6: Minimum water quality parameters to be used in testing waters in Lane Cove catchment.
Obviously, the more samples tested the greater the information that can be provided on the catchment and the more applications the information can receive , i.e it can be used to look at many different issues in the catchment) Where there are specific issues such as road runoff, or heavy metal pollution additional tests would be added to the list.
Re-education of the Streamwatch schools is required. Streamwatch schools have a very valuable contribution to make to water quality data collection. There are numerous schools involved, they are enthusiastic and have the potential to provide a lot of data on the catchment. However, the data they collect is sometimes unusual. For example, often the air temperature is recorded rather than the water temperature. Students and teachers alike must be re-informed about what they are collecting . There may be some value in an initiative between Streamwatch and schools to verify all data before it is accepted so that the data collected is not simply for the purposes of education but also makes a tangible addition to the water quality database.
4.2 Suggested sampling regimen for Lane Cove catchment
Scope 7.0 develop a rational data collection programme which can be coordinated between all involved parties which will effectively monitor future flow conditions and water quality.
Outlined below are a number of considerations for the design of the most effective water quality monitoring regimen for Lane Cove Catchment.
What is the ultimate
use of the information?
In order to design a sampling programme the use to which the
information is put must be considered. Community values are
important in assessing this. However, in most cases this will be
unknown so, as seen in the sub-catchment reports (section 3.0)
above, sampling will be as versatile as possible and therefore
try to cover as many streams as possible.
The sampling regimen suggested for Lane Cove is that seen in Appendix M. This map shows those sites used by AWT / Scientific services between 1989 and 1992. Appendix N gives references for the equivalent LCRCMC sites.
AWT were not sampling for a specific reason and so their regimen is applicable to the current requirements of LCRCMC. In addition to those sites in Appendix M, more sites would be required to monitor water quality south of the weir. The minimum number of sites below this point are WQ;
021, 035, 018, 026, 032, 007, 033, 019, 028, 008, 005, 006, 002, 003, 037 and 001.
In addition one regular sampling point should be considered in those sub-catchments which have not received any monitoring namely;
Kittys Creek, Eastwood, Tambourine Bay - West, Greenwich -West, Lane Cove industrial, Lane Cove River 6 and Hunters Hill
In Lane Cove catchment new sites to be monitored would be based on landuse and would include for example;
One important consideration is to what extent do areas impact on the water quality eg.: heavy metals from major roads and the M2., starch and wax, petrochemicals from S C Johnson etc
Cutting costs
If rationalisation is required, target the worst effected spots and the most likely potential sources of pollution as suggested by land use and knowledge gaps. However, if a long running programme would need to be sacrificed, it is more important to have a baseline, continuum of information.
In Hunters Hill, costs can be reduced and the maximum number of sub-catchments monitored by taking samples from each of the small drainage areas within each of the Lane Cove sub-catchments and combining and mixing the samples. The results obtained will be non-specific but will give an indication of water quality. The areas involved in Hunters Hill are quite small and the land use much the same so the differences between drainage ares would not be great.
The location of sampling is most economically done at steam confluences (joinings). One sample in the smaller stream just before it enters the larger one, and two on the larger stream (just up and down stream of the confluence) will by difference tell the effect that a stream is having. AWT / Scientific services have applied this technique when assessing the impact of Porters Creek. Another important considerations for the effective monitoring of water is the use of living organisms (macroinvertebrates) to monitor stream health. This is the ultimate test of stream health because a high bio-diversity shows that the waterbody is in equilibrium.
However, the initial sampling regimen should be based on gathering a wide range of sample points. As discussed above this selection is based on land use and the most likely sites to be polluted. Sampling all tributaries should be avoided, rather a concentration on a hierarchy with tributaries that are likely to have problems is recommended.
Once a sound baseline has been established (perhaps one or two years) then, the number of resources can be reduced and it will be possible to concentrate on event sampling rather than regular sampling.
Lane Cove River has a lot of water quality but it would not be considered good baseline data because;
Such a consultant does exist, John Laxton, who has been collecting water quality data monthly in Lane Cove catchment since 1986 and analysed it for a wide range of parameters.
Event sampling will reduce costs and provide more meaningful results since baseflow or low flow events reveal little of the extent of pollution and contamination. Also, event sampling gathers information on the worst case scenario and does not risk ‘missing’ an important occurrence because it does not coincide with a sampling day. Organisms such as macroinvertebrates are the most sensitive indicators of stream health and they are most affected by pulses, in particular the "first flush" (period directly after a rain event when the bulk of pollutants are washed into the waterways).
Other considerations
Further reading regarding the design of water quality sampling is referred to;
The following considerations should be borne in mid when undertaking similar projects to this. It identifies the steps involved in achieving the aims of this project, problems encountered and other incidental information.
