Our water quality monitoring program has shown Deep Creek to have good water quality. Find out more about the estuary and its unique features.
Deep Creek estuary is a medium-sized lagoon with an intermittently closed entrance. Located north of Nambucca Heads on the north coast of New South Wales, the estuary is typically open to the sea via a shallow constricted entrance.
Historically, artificial entrance opening has occurred at Deep Creek estuary when the lagoon has closed. The lower estuary supports a large area of tidal flats, mangroves and saltmarsh, and is a popular fishing and swimming spot.
Water quality report card
As part of our water quality monitoring program we assess the water quality and ecosystem health of an estuary using a range of relevant indicators. We sample a subset of the estuaries located between the Queensland border and Taree every 3 years. The most recent sampling in Deep Creek was completed over the 2018–19 summer, when 2 sites were sampled on a monthly basis.
This report card represents 2 water quality indicators that we routinely measure: the amount of algae present and water clarity. Low levels of these 2 indicators equate with good water quality.
B
Algae
C
Water clarity
B
Overall grade
The report card shows the condition of the estuary was good with:
algae abundance graded good (B)
water clarity graded fair (C)
overall estuary health graded good (B).
Grades for algae, water clarity and overall are represented as:
A – excellent
B – good
C – fair
D – poor
E – very poor.
Go to estuary report cards to find out what each grade means, read our sampling, data analysis and reporting protocols, and find out how we calculate these grades.
We have monitored water quality in the Deep Creek since 2012. This table shows the water quality grades for this estuary over that time.
Year
Algae
Water clarity
Overall grade
2012–13
B
C
B
2015–16
A
B
B
Physical characteristics
Estuary type
Lagoon
Latitude
–30.6 (ºS)
Longitude
153.01 (ºE)
Catchment area
89.8 km2
Estuary area
1.7 km2
Estuary volume
1387 ML
Average depth
1.3 m
Tidal exchange volume
Tidal exchange volume or tidal prism data is available for this estuary. This tidal prism was measured in 2002.
Tide state
Flow (ML)
Local tidal range (m)
Sydney Harbour tidal range (m)
Ebb flow
220
0.25
1.67
Flood flow
280
0.28
1.72
Notes: km2 = square kilometres; m = metres; m3 = cubic metres; ML = megalitres.
The Deep Creek catchment is highly disturbed. Most land-use change has been driven by grazing and horticulture throughout the valley. A lot of the low-lying area adjacent to the estuary and the steep upper reaches of the catchment remain as forest, making up most of the total catchment area.