Hearnes Lake

Our water quality monitoring program has shown Hearnes Lake to have fair water quality. Find out more about the estuary and its unique features.

Hearnes Lake is situated between Coffs Harbour and Woolgoolga on the New South Wales north coast. It is a lagoon with an intermittently closed entrance.

Estuary health and features

Water quality

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 Hearnes Lake was completed over the 2021–22 summer when 2 sites were sampled on a monthly basis.

Hearns Lake water quality report card for algae and water clarity showing colour-coded ratings (red, orange, yellow, light green and dark green, which represent very poor, poor, fair, good and excellent, respectively). Algae is rated 'fair' and water clarity is rated 'poor' giving an overall rating of 'fair' or 'C'.

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.

The report card shows the condition of the estuary was fair with:

  • algae abundance graded fair (C)
  • water clarity graded poor (D)
  • overall estuary health graded fair (C).

Coffs Harbour City Council, in collaboration with the University of New England’s EcoHealth Program, have carried out detailed ecosystem health monitoring in Hearnes Lake. The results of the monitoring program, including a detailed water quality report card, are available on the Coffs Harbour City Council website.

Find out more about our estuary report cards and 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 Hearnes Lake since 2009. This table shows the water quality grades for this estuary over that time.

Hearns Lake historic water quality grades from 2009-10 for algae and water clarity. Colour-coded ratings (red, orange, yellow, light green and dark green represent very poor (E), poor (D), fair (C), good (B) and excellent (A), respectively).

Grades for algae, water clarity and overall are represented as:

  • A – excellent
  • B – good
  • C – fair
  • D – poor
  • E – very poor.

Physical characteristics

Estuary type: Lagoon

Entrance
location
Latitude (ºS) –30.13
Longitude (ºE) 153.20
Catchment area (km2) 6.6
Estuary area (km2) 0.1
Estuary volume (ML) 37.8
Average depth (m) 0.4
Notes: km2 = square kilometres; m = metres; ML = megalitres.

Water depth and survey data

Bathymetric and coastal topography data for this estuary are available in our data portal.

Land use

Hearnes Lake receives water from a very highly disturbed catchment. Over two thirds of the catchment has been cleared of vegetation and a lot of this land, which lies west of the Pacific Highway, is used for horticulture. Urban areas comprise around 10% of the catchment.

National and marine parks

Community involvement

  • Coffs Harbour Regional Landcare provides workshops and volunteer work opportunities along the Coffs Coast.
  • There are 22 bushcare and landcare groups in the Coffs Harbour area, including in Hearnes Creek. These groups mainly work within the Coffs Coast Regional Park. For more information go to the National Parks and Wildlife Service Coffs Harbour bushcare and landcare webpage.
Hearns Lake