Quarry Creek monitoring

Council is monitoring Quarry Creek to check for any potential impacts arising from the construction works at Norman Griffiths Oval.

Council will monitor the site at least weekly. Around specific construction activities or weather events Council may monitor more frequently and will publish the data here.

Week commencing Monday 8 July

Light rainfall recorded early in the week, fining up towards the weekend. 

pH reader reported as not operating properly during the week, only Turbidity recorded until probe can be serviced.

Sediment removal from behind check dams in the creek undertaken with sandbags and coir logs maintained.

Water monitoring table

	Upstream (Lofberg Rd Channel)		Downstream (Norman Griffiths outlet cage)
	Turbidity (NTU)	pH	NTU	pH	Actions
Monday 8/7	10.7	N/A	25.5	N/A	Dewatering noted - turbidity level to be observed, NTU of 20.8 recorded at KFAC bridge, max NTU of 26.4 at the Streamwatch site - continue to observe.
Tuesday 9/7	10.3	N/A	23.5	N/A	Good - continue to observe.
Wednesday 10/7	4.9	N/A	31.7*	N/A	Downstream sample taken from first pool as contractors working near headwall, dewatering also noted - continue to observe - likely to be local disturbance due to works. NTU of 23.3 recorded at KFAC bridge, 15.2 at the Streamwatch site.
Thursday 11/7	7.4	N/A	11.8	N/A	Good - continue to observe.
Friday 12/7	5.6	N/A	6.2	N/A	Good - continue to observe.

Traffic lights key

Turbidity (NTU)	0 - 25	25.1 - 40	40.1+
pH	<5.5	5.6 - 6.4	6.5 - 8.3	8.4 - 9	9.1+

Previous weeks results

Frequently asked questions

Why are we monitoring the water quality of Quarry Creek? 

Council is monitoring Quarry Creek to check for any potential impacts arising from the construction works at Norman Griffiths Oval. Where potential issues can be identified early, actions can be taken to ensure we avoid irreversible damage to our local environment.

What are the water quality indicators that are being measured? 

The key water quality indicators currently being monitored are Turbidity and pH. 

Turbidity is a measure of how clear or cloudy a liquid is and can be an indicator of sediment being carried by the water. Turbidity is measured in NTUs and turbidity can vary drastically in urban waterways, primarily in response to rainfall, but also in response to soil type and even biological factors.

pH is a measure of how acidic the water is. Our waterways naturally vary in acidity depending on the local geology, soils, amount of urban development and fluctuations in flow and rainfall. Sudden changes in acidity can indicate the potential for a contaminant in the water.

Other indicators being regularly monitored include:

• Electrical Conductivity – provides an indication on the amount of salts in the water.
• Dissolved oxygen – whilst dissolved oxygen naturally fluctuates depending on time of day and flow conditions, unusually low levels of dissolved oxygen can be an indicator of a pollution event.

In addition, council has been undertaking additional water sampling that aligns with our Water Quality Monitoring Program. For details on this sampling program please see Water quality monitoring in Ku-ring-gai.

Where are the water samples being taken? 

Water samples are being taken from a number of different locations and catchment areas.

It is noted that it is difficult to sample the direct impacts of the Norman Griffiths Oval construction site on water quality, due to the stormwater connections that occur under the site, providing water contributions for additional catchment areas.

Sampling in the culvert/channel on the upstream side of Lofberg Rd does not include drainage from Lofberg Rd itself or the stormwater line that picks up the catchment around the intersection of Lofberg Rd and Shaddock Ave. It also does not account for the stormwater line that joins the main stormwater line between the existing pit on site and Quarry Creek. This line picks up the catchment around part of Kamilaroy Rd and properties on Andrew Ave.

Water monitoring locations

Sites 1. Upstream of Norman Griffiths Oval (channel on Lofberg Road). 2. At the Outlet Cage downstream of Norman Griffiths Oval.  3. Bridge to KFAC, upstream of Prince of Wales Drive 4. Stream Watch Monitoring Site (First Scout Hall bridge) 5. The ‘Lofberg Oval Tributary’ bridge adjacent to the dog-off leash area 6. Pipe beside the outlet cage.

Water catchment areas

*Please note catchment areas represented in the map are approximate

What is typical water quality of a creek located in an urban environment?

Urban development exerts significant pressures on local waterways. Due to the location of sewerage infrastructure near watercourses, and an increase in built impervious surfaces, creeks within Ku-ring-gai are increasingly becoming substitute transport pathways for wastes such as stormwater runoff and sewerage effluent. In addition, past land uses such as timber felling, orchards, farming, waste management and mining can have long term impacts. This results in generally poor quality water flowing through our urban creek environments.

Water quality impacts, coupled with the changes in flows that accompany urbanisation result in what is generally known as the ‘urban stream syndrome’ where a reduced level of aquatic biodiversity is able to survive harsh urban environments.  

Pollution in our creeks can generally be categorised as diffuse and point source pollution. Diffuse sources of pollution include factors or activities that may not be significant on an individual scale, but can add up over space or time to be significant, such as litter in our streets. Point-source pollution includes impacts from a specific identifiable source, such as sewer overflows or sediment laden run-off from building sites. 

In response to urban pollution there are ways to help manage stormwater and report possible point source incidents so they can be resolved. Council is currently progressing to become a Water Sensitive City Ku-ring-gai and has been incorporating stormwater harvesting and biofiltration projects to help reduce stormwater impacts in our catchments.

If you notice water pollution such as sediment, paint or chemicals in a local waterway or see someone dumping rubbish or garden waste into or near a waterway call Council 9424 0000.

If you notice sewerage in a waterway or overflowing from any infrastructure, contact Sydney Water on 13 20 90.

What are some factors that can impact water quality readings?

 Factors impacting water quality include (but are not limited to): 

• Rainfall.
• Temperature.
• Groundwater.
• Sewer overflows.
• Illegal connection of private sewage to stormwater infrastructure.
• Stormwater runoff.
• Industrial discharge.
• Organic material load.
• Land contamination.
• Fuel leaks and spills.
• Vehicle accidents and material spillage.
• Fire.
• Car/boat/house washing.
• Painting, particularly washing off brushes into a stormwater drain.
• Pool dewatering.
• Basement dewatering.
• Construction sites.
• Road works.

What measures are Council taking to protect Quarry Creek while work is being carried out at Norman Griffith Oval?

As required for all construction works, the contractors undertaking the work at Norman Griffiths oval are required to do under the provisions contained in an Environmental Management Plan (EMP). The EMP outlines the responsibilities in relation to environmental protection and construction site management, such as the management waste and materials on-site. 

The site is required to detain all site run-off for treatment prior to discharge, however a number of recent breaches have resulted in the loss of sediment laden water from the site.

As such, Council has implemented additional measures to ensure improved protection of Quarry Creek for the remainder of the construction phase of the project. In particular, regular water quality monitoring has commenced and will be continued for the remainder of construction.   

What measures are in place to improve the long term water quality at Quarry Creek?

There are a number of existing and proposed measures to protect and improve the water quality of Quarry Creek.

Bicentennial Park currently contains two Stormwater Quality Improvement Devices (SQUIDs): 

• The Quarry Creek trash rack is just upstream of Yanko Road and helps to filter coarse sediments, leaf litter and rubbish from the creek.
• The Lofberg Oval harvesting system and biofilter diverts high (storm) flows from the stormwater system and filters the water to provide irrigation for Lofberg Oval. The vegetated biofilter not only captures sediments and rubbish, it also helps to remove nutrients and heavy metals.  

In addition to the above, the Norman Griffiths Oval upgrade incorporates new measures that will help protect and improve creek water quality including:

• Filtration of all run-off prior to discharge from the site.
• New CDS unit, which provides treatment of flows from upstream of Lofberg Road. CDS units capture a wide range of pollutants such as rubbish, leaf litter and sediment.
• New biofiltration garden that will treat flows passing through the newly installed sub-surface flood detention system. This new biofilter will help to remove nutrients and heavy metals from the stormwater.

In addition, the Kooloona Crescent biofilter garden helps to improve the quality of urban run-off into Quarry Creek, along with all our residents in the catchment who have their own rain gardens and rainwater harvesting tanks.

Contact

Should you require further information please contact sfindlay@krg.nsw.gov.au or 9424 0000.