Anna Bay drainage an overloaded & complex system

Anna Bay drainage, overloaded & steeped in complexity

Presentation: Pierre Sidrow, South Tomaree Community Association
Editorial: Alex West, EcoNetwork

Pierre Sidorow, on behalf of the South Tomaree Community Association (STCA), presented a revealing situation on the Anna Bay drainage system at EcoNetwork’s recent Forum/AGM at the end of August 2025.

The presentation raised lots of questions about the suitability of current infrastructure and management systems.

Pierre suggested a collaboration with academia to fully explore possible future drainage management options.

Here is a summary of Pierre’s presentation and a proposed way ahead.

From simple beginnings a complex ‘system’ develops

In the late 1800s and early 1900s, local farming landowners dug the Anna Bay Main Drain to drain the Murrumburrimbah Swamp, a large area between Nelson Bay and Frost Roads, to facilitate their agricultural activity.

By 1910, the landowners formed the Anna Bay Drainage Trust (ABDU) to manage the drain.

In 1939 The Drainage Act (of NSW) was introduced. It provided for the drainage of land and control of flood waters by allowing the levy of rates and facilitating the administration of unions and trusts to manage drainage locally.

As a result, in 1942 the Anna Bay Drainage Union (ABDU) – a private water corporation was formed. It is one of 81 NSW Government listed private organisations with water management responsibilities.

In 2000, the Water Management Act (NSW) was introduced. It superseded the Drainage Act which was subsequently repealed. It allows for the sustainable and integrated management of the state’s water resources. It separates water licences from the land to allow tradable water access and recognises the need to support the ecological health of groundwater.

The current day drainage system is now far more complex and there are an estimated 25 km of drains – consisting of mostly open drains, pipes and culverts

A complex regulatory environment governs the ‘system’

Along with the Water Management Act 2000, ABDU must consider several other regulatory compliance hurdles including:

Protection of the Environment Operations Act 1997
Local Government Act 1993
Environmental Planning and Assessment Act 1979
Fisheries Management Act 1994
Biodiversity Conservation Act 2016

A rapidly growing issue and an under resourced Union

The situation is now exacerbated by regular flood prone areas, numerous residential plots and future plans for additional housing.

All this makes for an uncertain future for ABDU. There are currently only 5 landowners who are all Board members.

This is a depleted membership with insufficient resources to manage their responsibilities, which include maintenance operations, capital works, regulatory compliance and finance.

ABDU do not collect fees, instead relying on approximate $20k pa funding from Port Stephens Council. This funding is uncertain, and has dwindled over time. It’s looking likely that the ABDU may be dissolved in the next 2-5 years.

Looking to a way forward

There are ongoing complex drainage problems to be planned and managed, which Pierre says “needs ‘big brain’ involvement”.

Pierre and the STCA suggest engaging University research expertise by – for example – utilizing the PhD program.

PSC could sponsor the engagement to study and deliver short, medium and long-term plans.

Action is needed now.

Issues in a nutshell

The Anna Bay Drainage Trust, formed in 1910 to manage a simple agricultural drainage system, is under resourced, financially and professionally, to manage an agricultural and complex residential drainage system associated with a rapidly developing town.

The amount of proposed residential development, essentially on swampland, outstrips the drainage system’s capacity, exacerbated by the extent of proposed hardened surfaces.

New professional methodology is required to map a way forward.

South Tomaree Community Association & Pierre Sidrow, Anna Bay drainage presentation slides, 31 August 2025