MT13 Manage Nutrient Runoff

Myall Lakes is one of the largest coastal lake systems in New South Wales boasting over ten
thousand hectares of waterways set wholly within the Myall Lakes National Park. The Myall
Lakes system comprises a series of lakes including the Bombah Broadwater (lower lake),
Two Mile and Boolambayte Lakes (mid-lakes) and Myall Lake (upper lake). Feeding this lake
system is a catchment area of 78,000 hectares. The Myall and Crawford rivers are the main
tributaries to the lake system, feeding into Bombah Broadwater, while Boolambayte Creek
also supplies fresh water. The Lower Myall River connects this unique waterbody to the
ocean, allowing saltwater exchange from Port Stephens. Myall Lakes has significant
environmental and cultural value to the local, national and international community. The lake
system is recognised internationally under the Ramsar Convention as an important wetland,
and Myall Lakes National Park is a popular tourist destination for camping, bushwalking,
fishing, boating and water sports. A healthy lake system is integral to the culture and
economy of the local area.
In early 1999 Myall Lakes began to exhibit major signs of a natural system in trouble when a
large, toxic blue-green algae bloom formed in the lower section of the lakes. Blue-green algae
are a type of bacteria that act like plants by using light for photosynthesis. When conditions
are ideal they can multiply at a prolific rate resulting in a bloom. Potentially harmful algal
scums accumulated on the shores of the lake including at many popular camping areas. The
bloom persisted on-and-off until April 2001 having a major impact on the local community –
tourist numbers dropped and the lakes were intermittently closed to commercial and
recreational fishing. Blue-green algal blooms have continued to occur in the lakes since mid
2001, although not as severely as those experienced in 1999.
The initial algal bloom in 1999 left the Myall Lakes community extremely concerned about
the future of their unique natural asset. The State Government responded to these concerns by
initiating the ‘Monitoring Blue-Green Algae in Myall Lakes’ project - a partnership between
the then Department of Land and Water Conservation (DLWC; now Department of
Infrastructure, Planning, and Natural Resources [DIPNR]) and the NSW National Parks and
Wildlife Service (NPWS: now part of the Department of Environment and Conservation
[DEC]) with funding from the Federal Government’s Coasts and Clean Seas program.