Blue Lagoon Draft Management Plan

August 2025

After the community consultations with Council and our Consultants, North Barker.  A Blue Lagoon Weed Management Plan has been finalised and has been put up for approval at the next Council meeting.

Blue Lagoon Weed Mangement Plan Final July 2025

Update – January 2025

Whilst our Blue Lagoon Management Plan (BLMP) is still under development, one of the high priority areas identified during its development was weed management.

You can read about the development of the BLMP below. Council has provided funding to investigate management of the weeds at Blue Lagoon and have engaged North Barker Ecosystems Services to develop a Weed Management Plan.

We are holding a community workshop with the consultants to discuss the way forward to managing the weeds at Blue Lagoon. We invite key stakeholders and the local community to attend and have your say!

Details of workshop:

Thursday 20 February 2025

5pm to 7pm

Okines Community House

The workshop will discuss some of the focus activities from the BLMP plan:

• Protecting the lagoon from invasive weeds
• Planning for the staged removal of Pine trees and Cumbungi
• Community engagement in conservation and restoration activities for improved health and wellbeing

Plus any other issues raised at the workshop.

Next steps  

The Consultants will provide a draft report based upon the workshop feedback and their onsite survey.  The draft weed management plan will be published for stakeholder feedback, before being presented to Council for endorsement.

Please RSVP your attendance to the workshop by 10 February 2025 to sorell@sorell.tas.gov.au / or by phone 6269 0000.

The Blue Lagoon area is of high ecological importance and socio-cultural value.  It is surrounded by residential use, a public park / playground, road and parking infrastructure and the popular Blue Lagoon beach.

The review and update of the original 2008 BLMP responds to the need to take a broad approach to managing the co-existence of the natural environment with multiple users, residents and stakeholders. The draft BLMP seeks to balance these different values and characteristics of all users, identifies risks and proposes recommendations for mitigation/adaptation measures to ensure there is sustainability for flora, fauna and communities.

It sets out an overarching framework for sustainable management in partnership with local communities and stakeholders, with the aim to ensure the Lagoon is managed in a way that protects its biodiversity and meets the needs of the community, now and into the future.

Naturally, the Lagoon has endured periods of dry and wet seasons. Over recent years, increased water levels in the Lagoon mean there has been a flourishing of biodiversity which is highly valued (both ecologically and aesthetically) by many in the community.

It is also known that during dry seasons, Blue Lagoon has been subject to fire, arson and vandalism, and has been used as a dumping ground.

During significant wet periods, private properties, Boat Park and Kannah Street have been impacted by floodwater and this poses significant risk.

The frequency of extreme weather events has resulted in Council having to react to mitigate impacts to surrounding recreation, beach and residential areas.

Implementing the BLMP will facilitate more sustainable actions to cope with future weather events, while seeking to improve measuring and monitoring of key environmental health indicators.

The BLMP nominates an operating budget allocation for staged removal of Cumbungi commencing 2023/2024. The BLMP envisions cumbungi will be removed and managed to prevent future infestation.

The BLMP references a review in 3 years, however, it is intended to be a living document that is flexible and adaptable to enable the activities and actions implemented under the BLMP to be assessed, re-evaluated and amended or new actions proposed at key milestones.

This includes Council taking into consideration stakeholders and local community feedback based on their ongoing investment in the care and maintenance of the Blue Lagoon Reserve and surrounding coastline.

As a wetland, Blue Lagoon has (and continues to be) a natural capture for water runoff and a filtration system.

The BLMP includes details on what has been investigated by Council as stormwater options to manage the risk of inundation and impacts to the receiving water. Stormwater has (and will) continue to find its way to the Lagoon given the topography and geomorphology. The Lagoon acts as a filter for sediments, Total Suspended Solids (TSS) and to decrease the nutrient concentration. Elsewhere in Australia other councils have invested heavily to create man-made lagoons to filter (biologically) water before entering waterways.

We are currently seeking an independent review of stormwater management options.  The recommendations from this review will be incorporated into the BLMP and redistributed for community consultation.

The Development Application (DA 5.2022.99.1) referenced within the BLMP is on hold pending the outcomes of the review and the separate Federal EPBC (Environmental Protection and Biodiversity Conservation) assessment process.

The DA is referenced in the BLMP for context only and to identify what studies have been used to develop the stormwater management proposal to date.

Stormwater management is one of a range of elements set out under the BLMP that contribute to ensuring the future protection of the wetland’s biodiversity.

The statutory process for the DA falls under the assessment requirements of the Planning Scheme. This is separate to the BLMP, however, the management plan can provide guidance to the planning authority. Updates on the DA status will be provided on the Council’s website, including when further statutory notification is to occur.

During the time of a peak flood, as per the Entura Stormwater System Management Plan (SSMP) modelling, the proposed DN600 outfall is capable of discharging about 300 L/s for 12 hours duration. The modelling only considered peak flow and not event volume. Significant additional investigation would be required of the catchment hydrodynamics to calculate the exact volume of water during a Q100 rainfall event (i.e. 1 in 100 year).

The proposed permanent stormwater outfall option will be considered as part of the independent review.

This is unlikely as their removal will be staged over time to enable plantation of suitable alternative native species. This will occur simultaneously.

Pine trees have established themselves over decades and provide important habitat for some of the fauna in the lagoon. Removing them completely in a short period of time is not considered best practice.

The BLMP considers the recommendations and actions identified in the Strategy to ensure alignment is achieved where possible.  In particular, with regard to access locations #42, #44, #45 and #46. The BLMP acknowledges the underlying principles of the Strategy including Principles 1 – 6.

The BLMP acknowledges maintenance and management is key to sustainable use of the foreshore. Council will continue to work with the State government to ensure suitable access to the Crown coastal reserve is provided.  Defined Blue Lagoon walking trails with regular inspections and monitoring will reduce, and ideally eliminate unauthorised access of the foreshore.

It has not been fully considered as a management practice due to the potential to cause major ecological impacts. This would require further expert investigation.

In the last few years, there has been confirmation of Red Handfish being located in the Sorell Municipality with greater community awareness around the conservation of the species.

As a critically endangered species, Council is working directly with major stakeholders including IMAS to facilitate protection, education and understanding of this species. Council and the community can play an important part in supporting the protection of the species. Further, the potential impact on the receiving waters from the proposed Blue Lagoon intermittent overflows is currently being assessed as part of the EPBC process.