Back Lagoon is located on the south coast of New South Wales on the outskirts of Merimbula. It is classed as a lagoon with an intermittently closed entrance. The entrance is managed by Bega Valley Shire Council to reduce impacts of foreshore inundation.
This estuary is particularly dynamic due to the relatively large size of the catchment compared to the lake. The estuary supports extensive seagrass beds.
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 between Wollongong and the Victorian border every 3 years. The most recent sampling in Back Lagoon was completed over the 2017–18 summer, when 2 sites were sampled on a monthly basis.
Algae
Water clarity
Overall grade
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 excellent with:
- algae abundance graded excellent (A)
- water clarity graded excellent (A)
- overall estuary health graded excellent (A).
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.
Physical characteristics
| Estuary type | Lagoon |
|---|---|
| Latitude | –36.88 (ºS) |
| Longitude | 149.93 (ºE) |
| Catchment area | 31.4 km2 |
| Estuary area | 0.4 km2 |
| Estuary volume | 215.9 ML |
| Average depth | 0.6 m |
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
The catchment of Back Lagoon has low disturbance, with over 80% remaining forested. Urban and grazing areas each occupy about 5% of the catchment.
National and marine parks
- No conservation areas are located within this catchment.
- This estuary does not flow into a marine park.
Community involvement
- The Far South Coast Landcare Association is a volunteer environmental and conservation organisation that works to improve management of local land and water.
Aerial view of Back Lagoon.
Local government management
Local councils manage estuaries within their area unless the estuary is attached to a marine park. Bega Valley Shire Council manages this estuary.
Threatened species
Back Lagoon estuary supports extensive seagrass meadows and is home to a number of other estuarine species.
Find out more about the biodiversity in our estuaries.